OSCL-LXR linux-6.0.1/​drivers/​nvme/​host/​core.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 /*
  * NVM Express device driver
  * Copyright (c) 2011-2014, Intel Corporation.
  */
 
 #include <linux/blkdev.h>
 #include <linux/blk-mq.h>
 #include <linux/blk-integrity.h>
 #include <linux/compat.h>
 #include <linux/delay.h>
 #include <linux/errno.h>
 #include <linux/hdreg.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/backing-dev.h>
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/pr.h>
 #include <linux/ptrace.h>
 #include <linux/nvme_ioctl.h>
 #include <linux/pm_qos.h>
 #include <asm/unaligned.h>
 
 #include "nvme.h"
 #include "fabrics.h"
 #include <linux/nvme-auth.h>
 
 #define CREATE_TRACE_POINTS
 #include "trace.h"
 
 #define NVME_MINORS     (1U << MINORBITS)
 
 struct nvme_ns_info {
     struct nvme_ns_ids ids;
     u32 nsid;
     __le32 anagrpid;
     bool is_shared;
     bool is_readonly;
     bool is_ready;
 };
 
 unsigned int admin_timeout = 60;
 module_param(admin_timeout, uint, 0644);
 MODULE_PARM_DESC(admin_timeout, "timeout in seconds for admin commands");
 EXPORT_SYMBOL_GPL(admin_timeout);
 
 unsigned int nvme_io_timeout = 30;
 module_param_named(io_timeout, nvme_io_timeout, uint, 0644);
 MODULE_PARM_DESC(io_timeout, "timeout in seconds for I/O");
 EXPORT_SYMBOL_GPL(nvme_io_timeout);
 
 static unsigned char shutdown_timeout = 5;
 module_param(shutdown_timeout, byte, 0644);
 MODULE_PARM_DESC(shutdown_timeout, "timeout in seconds for controller shutdown");
 
 static u8 nvme_max_retries = 5;
 module_param_named(max_retries, nvme_max_retries, byte, 0644);
 MODULE_PARM_DESC(max_retries, "max number of retries a command may have");
 
 static unsigned long default_ps_max_latency_us = 100000;
 module_param(default_ps_max_latency_us, ulong, 0644);
 MODULE_PARM_DESC(default_ps_max_latency_us,
          "max power saving latency for new devices; use PM QOS to change per device");
 
 static bool force_apst;
 module_param(force_apst, bool, 0644);
 MODULE_PARM_DESC(force_apst, "allow APST for newly enumerated devices even if quirked off");
 
 static unsigned long apst_primary_timeout_ms = 100;
 module_param(apst_primary_timeout_ms, ulong, 0644);
 MODULE_PARM_DESC(apst_primary_timeout_ms,
     "primary APST timeout in ms");
 
 static unsigned long apst_secondary_timeout_ms = 2000;
 module_param(apst_secondary_timeout_ms, ulong, 0644);
 MODULE_PARM_DESC(apst_secondary_timeout_ms,
     "secondary APST timeout in ms");
 
 static unsigned long apst_primary_latency_tol_us = 15000;
 module_param(apst_primary_latency_tol_us, ulong, 0644);
 MODULE_PARM_DESC(apst_primary_latency_tol_us,
     "primary APST latency tolerance in us");
 
 static unsigned long apst_secondary_latency_tol_us = 100000;
 module_param(apst_secondary_latency_tol_us, ulong, 0644);
 MODULE_PARM_DESC(apst_secondary_latency_tol_us,
     "secondary APST latency tolerance in us");
 
 /*
  * nvme_wq - hosts nvme related works that are not reset or delete
  * nvme_reset_wq - hosts nvme reset works
  * nvme_delete_wq - hosts nvme delete works
  *
  * nvme_wq will host works such as scan, aen handling, fw activation,
  * keep-alive, periodic reconnects etc. nvme_reset_wq
  * runs reset works which also flush works hosted on nvme_wq for
  * serialization purposes. nvme_delete_wq host controller deletion
  * works which flush reset works for serialization.
  */
 struct workqueue_struct *nvme_wq;
 EXPORT_SYMBOL_GPL(nvme_wq);
 
 struct workqueue_struct *nvme_reset_wq;
 EXPORT_SYMBOL_GPL(nvme_reset_wq);
 
 struct workqueue_struct *nvme_delete_wq;
 EXPORT_SYMBOL_GPL(nvme_delete_wq);
 
 static LIST_HEAD(nvme_subsystems);
 static DEFINE_MUTEX(nvme_subsystems_lock);
 
 static DEFINE_IDA(nvme_instance_ida);
 static dev_t nvme_ctrl_base_chr_devt;
 static struct class *nvme_class;
 static struct class *nvme_subsys_class;
 
 static DEFINE_IDA(nvme_ns_chr_minor_ida);
 static dev_t nvme_ns_chr_devt;
 static struct class *nvme_ns_chr_class;
 
 static void nvme_put_subsystem(struct nvme_subsystem *subsys);
 static void nvme_remove_invalid_namespaces(struct nvme_ctrl *ctrl,
                        unsigned nsid);
 static void nvme_update_keep_alive(struct nvme_ctrl *ctrl,
                    struct nvme_command *cmd);
 
 void nvme_queue_scan(struct nvme_ctrl *ctrl)
 {
     /*
      * Only new queue scan work when admin and IO queues are both alive
      */
     if (ctrl->state == NVME_CTRL_LIVE && ctrl->tagset)
         queue_work(nvme_wq, &ctrl->scan_work);
 }
 
 /*
  * Use this function to proceed with scheduling reset_work for a controller
  * that had previously been set to the resetting state. This is intended for
  * code paths that can't be interrupted by other reset attempts. A hot removal
  * may prevent this from succeeding.
  */
 int nvme_try_sched_reset(struct nvme_ctrl *ctrl)
 {
     if (ctrl->state != NVME_CTRL_RESETTING)
         return -EBUSY;
     if (!queue_work(nvme_reset_wq, &ctrl->reset_work))
         return -EBUSY;
     return 0;
 }
 EXPORT_SYMBOL_GPL(nvme_try_sched_reset);
 
 static void nvme_failfast_work(struct work_struct *work)
 {
     struct nvme_ctrl *ctrl = container_of(to_delayed_work(work),
             struct nvme_ctrl, failfast_work);
 
     if (ctrl->state != NVME_CTRL_CONNECTING)
         return;
 
     set_bit(NVME_CTRL_FAILFAST_EXPIRED, &ctrl->flags);
     dev_info(ctrl->device, "failfast expired\n");
     nvme_kick_requeue_lists(ctrl);
 }
 
 static inline void nvme_start_failfast_work(struct nvme_ctrl *ctrl)
 {
     if (!ctrl->opts || ctrl->opts->fast_io_fail_tmo == -1)
         return;
 
     schedule_delayed_work(&ctrl->failfast_work,
                   ctrl->opts->fast_io_fail_tmo * HZ);
 }
 
 static inline void nvme_stop_failfast_work(struct nvme_ctrl *ctrl)
 {
     if (!ctrl->opts)
         return;
 
     cancel_delayed_work_sync(&ctrl->failfast_work);
     clear_bit(NVME_CTRL_FAILFAST_EXPIRED, &ctrl->flags);
 }
 
 
 int nvme_reset_ctrl(struct nvme_ctrl *ctrl)
 {
     if (!nvme_change_ctrl_state(ctrl, NVME_CTRL_RESETTING))
         return -EBUSY;
     if (!queue_work(nvme_reset_wq, &ctrl->reset_work))
         return -EBUSY;
     return 0;
 }
 EXPORT_SYMBOL_GPL(nvme_reset_ctrl);
 
 int nvme_reset_ctrl_sync(struct nvme_ctrl *ctrl)
 {
     int ret;
 
     ret = nvme_reset_ctrl(ctrl);
     if (!ret) {
         flush_work(&ctrl->reset_work);
         if (ctrl->state != NVME_CTRL_LIVE)
             ret = -ENETRESET;
     }
 
     return ret;
 }
 
 static void nvme_do_delete_ctrl(struct nvme_ctrl *ctrl)
 {
     dev_info(ctrl->device,
          "Removing ctrl: NQN \"%s\"\n", nvmf_ctrl_subsysnqn(ctrl));
 
     flush_work(&ctrl->reset_work);
     nvme_stop_ctrl(ctrl);
     nvme_remove_namespaces(ctrl);
     ctrl->ops->delete_ctrl(ctrl);
     nvme_uninit_ctrl(ctrl);
 }
 
 static void nvme_delete_ctrl_work(struct work_struct *work)
 {
     struct nvme_ctrl *ctrl =
         container_of(work, struct nvme_ctrl, delete_work);
 
     nvme_do_delete_ctrl(ctrl);
 }
 
 int nvme_delete_ctrl(struct nvme_ctrl *ctrl)
 {
     if (!nvme_change_ctrl_state(ctrl, NVME_CTRL_DELETING))
         return -EBUSY;
     if (!queue_work(nvme_delete_wq, &ctrl->delete_work))
         return -EBUSY;
     return 0;
 }
 EXPORT_SYMBOL_GPL(nvme_delete_ctrl);
 
 static void nvme_delete_ctrl_sync(struct nvme_ctrl *ctrl)
 {
     /*
      * Keep a reference until nvme_do_delete_ctrl() complete,
      * since ->delete_ctrl can free the controller.
      */
     nvme_get_ctrl(ctrl);
     if (nvme_change_ctrl_state(ctrl, NVME_CTRL_DELETING))
         nvme_do_delete_ctrl(ctrl);
     nvme_put_ctrl(ctrl);
 }
 
 static blk_status_t nvme_error_status(u16 status)
 {
     switch (status & 0x7ff) {
     case NVME_SC_SUCCESS:
         return BLK_STS_OK;
     case NVME_SC_CAP_EXCEEDED:
         return BLK_STS_NOSPC;
     case NVME_SC_LBA_RANGE:
     case NVME_SC_CMD_INTERRUPTED:
     case NVME_SC_NS_NOT_READY:
         return BLK_STS_TARGET;
     case NVME_SC_BAD_ATTRIBUTES:
     case NVME_SC_ONCS_NOT_SUPPORTED:
     case NVME_SC_INVALID_OPCODE:
     case NVME_SC_INVALID_FIELD:
     case NVME_SC_INVALID_NS:
         return BLK_STS_NOTSUPP;
     case NVME_SC_WRITE_FAULT:
     case NVME_SC_READ_ERROR:
     case NVME_SC_UNWRITTEN_BLOCK:
     case NVME_SC_ACCESS_DENIED:
     case NVME_SC_READ_ONLY:
     case NVME_SC_COMPARE_FAILED:
         return BLK_STS_MEDIUM;
     case NVME_SC_GUARD_CHECK:
     case NVME_SC_APPTAG_CHECK:
     case NVME_SC_REFTAG_CHECK:
     case NVME_SC_INVALID_PI:
         return BLK_STS_PROTECTION;
     case NVME_SC_RESERVATION_CONFLICT:
         return BLK_STS_NEXUS;
     case NVME_SC_HOST_PATH_ERROR:
         return BLK_STS_TRANSPORT;
     case NVME_SC_ZONE_TOO_MANY_ACTIVE:
         return BLK_STS_ZONE_ACTIVE_RESOURCE;
     case NVME_SC_ZONE_TOO_MANY_OPEN:
         return BLK_STS_ZONE_OPEN_RESOURCE;
     default:
         return BLK_STS_IOERR;
     }
 }
 
 static void nvme_retry_req(struct request *req)
 {
     unsigned long delay = 0;
     u16 crd;
 
     /* The mask and shift result must be <= 3 */
     crd = (nvme_req(req)->status & NVME_SC_CRD) >> 11;
     if (crd)
         delay = nvme_req(req)->ctrl->crdt[crd - 1] * 100;
 
     nvme_req(req)->retries++;
     blk_mq_requeue_request(req, false);
     blk_mq_delay_kick_requeue_list(req->q, delay);
 }
 
 static void nvme_log_error(struct request *req)
 {
     struct nvme_ns *ns = req->q->queuedata;
     struct nvme_request *nr = nvme_req(req);
 
     if (ns) {
         pr_err_ratelimited("%s: %s(0x%x) @ LBA %llu, %llu blocks, %s (sct 0x%x / sc 0x%x) %s%s\n",
                ns->disk ? ns->disk->disk_name : "?",
                nvme_get_opcode_str(nr->cmd->common.opcode),
                nr->cmd->common.opcode,
                (unsigned long long)nvme_sect_to_lba(ns, blk_rq_pos(req)),
                (unsigned long long)blk_rq_bytes(req) >> ns->lba_shift,
                nvme_get_error_status_str(nr->status),
                nr->status >> 8 & 7, /* Status Code Type */
                nr->status & 0xff,   /* Status Code */
                nr->status & NVME_SC_MORE ? "MORE " : "",
                nr->status & NVME_SC_DNR  ? "DNR "  : "");
         return;
     }
 
     pr_err_ratelimited("%s: %s(0x%x), %s (sct 0x%x / sc 0x%x) %s%s\n",
                dev_name(nr->ctrl->device),
                nvme_get_admin_opcode_str(nr->cmd->common.opcode),
                nr->cmd->common.opcode,
                nvme_get_error_status_str(nr->status),
                nr->status >> 8 & 7, /* Status Code Type */
                nr->status & 0xff,   /* Status Code */
                nr->status & NVME_SC_MORE ? "MORE " : "",
                nr->status & NVME_SC_DNR  ? "DNR "  : "");
 }
 
 enum nvme_disposition {
     COMPLETE,
     RETRY,
     FAILOVER,
     AUTHENTICATE,
 };
 
 static inline enum nvme_disposition nvme_decide_disposition(struct request *req)
 {
     if (likely(nvme_req(req)->status == 0))
         return COMPLETE;
 
     if ((nvme_req(req)->status & 0x7ff) == NVME_SC_AUTH_REQUIRED)
         return AUTHENTICATE;
 
     if (blk_noretry_request(req) ||
         (nvme_req(req)->status & NVME_SC_DNR) ||
         nvme_req(req)->retries >= nvme_max_retries)
         return COMPLETE;
 
     if (req->cmd_flags & REQ_NVME_MPATH) {
         if (nvme_is_path_error(nvme_req(req)->status) ||
             blk_queue_dying(req->q))
             return FAILOVER;
     } else {
         if (blk_queue_dying(req->q))
             return COMPLETE;
     }
 
     return RETRY;
 }
 
 static inline void nvme_end_req_zoned(struct request *req)
 {
     if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) &&
         req_op(req) == REQ_OP_ZONE_APPEND)
         req->__sector = nvme_lba_to_sect(req->q->queuedata,
             le64_to_cpu(nvme_req(req)->result.u64));
 }
 
 static inline void nvme_end_req(struct request *req)
 {
     blk_status_t status = nvme_error_status(nvme_req(req)->status);
 
     if (unlikely(nvme_req(req)->status && !(req->rq_flags & RQF_QUIET)))
         nvme_log_error(req);
     nvme_end_req_zoned(req);
     nvme_trace_bio_complete(req);
     blk_mq_end_request(req, status);
 }
 
 void nvme_complete_rq(struct request *req)
 {
     struct nvme_ctrl *ctrl = nvme_req(req)->ctrl;
 
     trace_nvme_complete_rq(req);
     nvme_cleanup_cmd(req);
 
     if (ctrl->kas)
         ctrl->comp_seen = true;
 
     switch (nvme_decide_disposition(req)) {
     case COMPLETE:
         nvme_end_req(req);
         return;
     case RETRY:
         nvme_retry_req(req);
         return;
     case FAILOVER:
         nvme_failover_req(req);
         return;
     case AUTHENTICATE:
 #ifdef CONFIG_NVME_AUTH
         queue_work(nvme_wq, &ctrl->dhchap_auth_work);
         nvme_retry_req(req);
 #else
         nvme_end_req(req);
 #endif
         return;
     }
 }
 EXPORT_SYMBOL_GPL(nvme_complete_rq);
 
 void nvme_complete_batch_req(struct request *req)
 {
     trace_nvme_complete_rq(req);
     nvme_cleanup_cmd(req);
     nvme_end_req_zoned(req);
 }
 EXPORT_SYMBOL_GPL(nvme_complete_batch_req);
 
 /*
  * Called to unwind from ->queue_rq on a failed command submission so that the
  * multipathing code gets called to potentially failover to another path.
  * The caller needs to unwind all transport specific resource allocations and
  * must return propagate the return value.
  */
 blk_status_t nvme_host_path_error(struct request *req)
 {
     nvme_req(req)->status = NVME_SC_HOST_PATH_ERROR;
     blk_mq_set_request_complete(req);
     nvme_complete_rq(req);
     return BLK_STS_OK;
 }
 EXPORT_SYMBOL_GPL(nvme_host_path_error);
 
 bool nvme_cancel_request(struct request *req, void *data)
 {
     dev_dbg_ratelimited(((struct nvme_ctrl *) data)->device,
                 "Cancelling I/O %d", req->tag);
 
     /* don't abort one completed request */
     if (blk_mq_request_completed(req))
         return true;
 
     nvme_req(req)->status = NVME_SC_HOST_ABORTED_CMD;
     nvme_req(req)->flags |= NVME_REQ_CANCELLED;
     blk_mq_complete_request(req);
     return true;
 }
 EXPORT_SYMBOL_GPL(nvme_cancel_request);
 
 void nvme_cancel_tagset(struct nvme_ctrl *ctrl)
 {
     if (ctrl->tagset) {
         blk_mq_tagset_busy_iter(ctrl->tagset,
                 nvme_cancel_request, ctrl);
         blk_mq_tagset_wait_completed_request(ctrl->tagset);
     }
 }
 EXPORT_SYMBOL_GPL(nvme_cancel_tagset);
 
 void nvme_cancel_admin_tagset(struct nvme_ctrl *ctrl)
 {
     if (ctrl->admin_tagset) {
         blk_mq_tagset_busy_iter(ctrl->admin_tagset,
                 nvme_cancel_request, ctrl);
         blk_mq_tagset_wait_completed_request(ctrl->admin_tagset);
     }
 }
 EXPORT_SYMBOL_GPL(nvme_cancel_admin_tagset);
 
 bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
         enum nvme_ctrl_state new_state)
 {
     enum nvme_ctrl_state old_state;
     unsigned long flags;
     bool changed = false;
 
     spin_lock_irqsave(&ctrl->lock, flags);
 
     old_state = ctrl->state;
     switch (new_state) {
     case NVME_CTRL_LIVE:
         switch (old_state) {
         case NVME_CTRL_NEW:
         case NVME_CTRL_RESETTING:
         case NVME_CTRL_CONNECTING:
             changed = true;
             fallthrough;
         default:
             break;
         }
         break;
     case NVME_CTRL_RESETTING:
         switch (old_state) {
         case NVME_CTRL_NEW:
         case NVME_CTRL_LIVE:
             changed = true;
             fallthrough;
         default:
             break;
         }
         break;
     case NVME_CTRL_CONNECTING:
         switch (old_state) {
         case NVME_CTRL_NEW:
         case NVME_CTRL_RESETTING:
             changed = true;
             fallthrough;
         default:
             break;
         }
         break;
     case NVME_CTRL_DELETING:
         switch (old_state) {
         case NVME_CTRL_LIVE:
         case NVME_CTRL_RESETTING:
         case NVME_CTRL_CONNECTING:
             changed = true;
             fallthrough;
         default:
             break;
         }
         break;
     case NVME_CTRL_DELETING_NOIO:
         switch (old_state) {
         case NVME_CTRL_DELETING:
         case NVME_CTRL_DEAD:
             changed = true;
             fallthrough;
         default:
             break;
         }
         break;
     case NVME_CTRL_DEAD:
         switch (old_state) {
         case NVME_CTRL_DELETING:
             changed = true;
             fallthrough;
         default:
             break;
         }
         break;
     default:
         break;
     }
 
     if (changed) {
         ctrl->state = new_state;
         wake_up_all(&ctrl->state_wq);
     }
 
     spin_unlock_irqrestore(&ctrl->lock, flags);
     if (!changed)
         return false;
 
     if (ctrl->state == NVME_CTRL_LIVE) {
         if (old_state == NVME_CTRL_CONNECTING)
             nvme_stop_failfast_work(ctrl);
         nvme_kick_requeue_lists(ctrl);
     } else if (ctrl->state == NVME_CTRL_CONNECTING &&
         old_state == NVME_CTRL_RESETTING) {
         nvme_start_failfast_work(ctrl);
     }
     return changed;
 }
 EXPORT_SYMBOL_GPL(nvme_change_ctrl_state);
 
 /*
  * Returns true for sink states that can't ever transition back to live.
  */
 static bool nvme_state_terminal(struct nvme_ctrl *ctrl)
 {
     switch (ctrl->state) {
     case NVME_CTRL_NEW:
     case NVME_CTRL_LIVE:
     case NVME_CTRL_RESETTING:
     case NVME_CTRL_CONNECTING:
         return false;
     case NVME_CTRL_DELETING:
     case NVME_CTRL_DELETING_NOIO:
     case NVME_CTRL_DEAD:
         return true;
     default:
         WARN_ONCE(1, "Unhandled ctrl state:%d", ctrl->state);
         return true;
     }
 }
 
 /*
  * Waits for the controller state to be resetting, or returns false if it is
  * not possible to ever transition to that state.
  */
 bool nvme_wait_reset(struct nvme_ctrl *ctrl)
 {
     wait_event(ctrl->state_wq,
            nvme_change_ctrl_state(ctrl, NVME_CTRL_RESETTING) ||
            nvme_state_terminal(ctrl));
     return ctrl->state == NVME_CTRL_RESETTING;
 }
 EXPORT_SYMBOL_GPL(nvme_wait_reset);
 
 static void nvme_free_ns_head(struct kref *ref)
 {
     struct nvme_ns_head *head =
         container_of(ref, struct nvme_ns_head, ref);
 
     nvme_mpath_remove_disk(head);
     ida_free(&head->subsys->ns_ida, head->instance);
     cleanup_srcu_struct(&head->srcu);
     nvme_put_subsystem(head->subsys);
     kfree(head);
 }
 
 bool nvme_tryget_ns_head(struct nvme_ns_head *head)
 {
     return kref_get_unless_zero(&head->ref);
 }
 
 void nvme_put_ns_head(struct nvme_ns_head *head)
 {
     kref_put(&head->ref, nvme_free_ns_head);
 }
 
 static void nvme_free_ns(struct kref *kref)
 {
     struct nvme_ns *ns = container_of(kref, struct nvme_ns, kref);
 
     put_disk(ns->disk);
     nvme_put_ns_head(ns->head);
     nvme_put_ctrl(ns->ctrl);
     kfree(ns);
 }
 
 static inline bool nvme_get_ns(struct nvme_ns *ns)
 {
     return kref_get_unless_zero(&ns->kref);
 }
 
 void nvme_put_ns(struct nvme_ns *ns)
 {
     kref_put(&ns->kref, nvme_free_ns);
 }
 EXPORT_SYMBOL_NS_GPL(nvme_put_ns, NVME_TARGET_PASSTHRU);
 
 static inline void nvme_clear_nvme_request(struct request *req)
 {
     nvme_req(req)->status = 0;
     nvme_req(req)->retries = 0;
     nvme_req(req)->flags = 0;
     req->rq_flags |= RQF_DONTPREP;
 }
 
 /* initialize a passthrough request */
 void nvme_init_request(struct request *req, struct nvme_command *cmd)
 {
     if (req->q->queuedata)
         req->timeout = NVME_IO_TIMEOUT;
     else /* no queuedata implies admin queue */
         req->timeout = NVME_ADMIN_TIMEOUT;
 
     /* passthru commands should let the driver set the SGL flags */
     cmd->common.flags &= ~NVME_CMD_SGL_ALL;
 
     req->cmd_flags |= REQ_FAILFAST_DRIVER;
     if (req->mq_hctx->type == HCTX_TYPE_POLL)
         req->cmd_flags |= REQ_POLLED;
     nvme_clear_nvme_request(req);
     memcpy(nvme_req(req)->cmd, cmd, sizeof(*cmd));
 }
 EXPORT_SYMBOL_GPL(nvme_init_request);
 
 /*
  * For something we're not in a state to send to the device the default action
  * is to busy it and retry it after the controller state is recovered.  However,
  * if the controller is deleting or if anything is marked for failfast or
  * nvme multipath it is immediately failed.
  *
  * Note: commands used to initialize the controller will be marked for failfast.
  * Note: nvme cli/ioctl commands are marked for failfast.
  */
 blk_status_t nvme_fail_nonready_command(struct nvme_ctrl *ctrl,
         struct request *rq)
 {
     if (ctrl->state != NVME_CTRL_DELETING_NOIO &&
         ctrl->state != NVME_CTRL_DELETING &&
         ctrl->state != NVME_CTRL_DEAD &&
         !test_bit(NVME_CTRL_FAILFAST_EXPIRED, &ctrl->flags) &&
         !blk_noretry_request(rq) && !(rq->cmd_flags & REQ_NVME_MPATH))
         return BLK_STS_RESOURCE;
     return nvme_host_path_error(rq);
 }
 EXPORT_SYMBOL_GPL(nvme_fail_nonready_command);
 
 bool __nvme_check_ready(struct nvme_ctrl *ctrl, struct request *rq,
         bool queue_live)
 {
     struct nvme_request *req = nvme_req(rq);
 
     /*
      * currently we have a problem sending passthru commands
      * on the admin_q if the controller is not LIVE because we can't
      * make sure that they are going out after the admin connect,
      * controller enable and/or other commands in the initialization
      * sequence. until the controller will be LIVE, fail with
      * BLK_STS_RESOURCE so that they will be rescheduled.
      */
     if (rq->q == ctrl->admin_q && (req->flags & NVME_REQ_USERCMD))
         return false;
 
     if (ctrl->ops->flags & NVME_F_FABRICS) {
         /*
          * Only allow commands on a live queue, except for the connect
          * command, which is require to set the queue live in the
          * appropinquate states.
          */
         switch (ctrl->state) {
         case NVME_CTRL_CONNECTING:
             if (blk_rq_is_passthrough(rq) && nvme_is_fabrics(req->cmd) &&
                 (req->cmd->fabrics.fctype == nvme_fabrics_type_connect ||
                  req->cmd->fabrics.fctype == nvme_fabrics_type_auth_send ||
                  req->cmd->fabrics.fctype == nvme_fabrics_type_auth_receive))
                 return true;
             break;
         default:
             break;
         case NVME_CTRL_DEAD:
             return false;
         }
     }
 
     return queue_live;
 }
 EXPORT_SYMBOL_GPL(__nvme_check_ready);
 
 static inline void nvme_setup_flush(struct nvme_ns *ns,
         struct nvme_command *cmnd)
 {
     memset(cmnd, 0, sizeof(*cmnd));
     cmnd->common.opcode = nvme_cmd_flush;
     cmnd->common.nsid = cpu_to_le32(ns->head->ns_id);
 }
 
 static blk_status_t nvme_setup_discard(struct nvme_ns *ns, struct request *req,
         struct nvme_command *cmnd)
 {
     unsigned short segments = blk_rq_nr_discard_segments(req), n = 0;
     struct nvme_dsm_range *range;
     struct bio *bio;
 
     /*
      * Some devices do not consider the DSM 'Number of Ranges' field when
      * determining how much data to DMA. Always allocate memory for maximum
      * number of segments to prevent device reading beyond end of buffer.
      */
     static const size_t alloc_size = sizeof(*range) * NVME_DSM_MAX_RANGES;
 
     range = kzalloc(alloc_size, GFP_ATOMIC | __GFP_NOWARN);
     if (!range) {
         /*
          * If we fail allocation our range, fallback to the controller
          * discard page. If that's also busy, it's safe to return
          * busy, as we know we can make progress once that's freed.
          */
         if (test_and_set_bit_lock(0, &ns->ctrl->discard_page_busy))
             return BLK_STS_RESOURCE;
 
         range = page_address(ns->ctrl->discard_page);
     }
 
     __rq_for_each_bio(bio, req) {
         u64 slba = nvme_sect_to_lba(ns, bio->bi_iter.bi_sector);
         u32 nlb = bio->bi_iter.bi_size >> ns->lba_shift;
 
         if (n < segments) {
             range[n].cattr = cpu_to_le32(0);
             range[n].nlb = cpu_to_le32(nlb);
             range[n].slba = cpu_to_le64(slba);
         }
         n++;
     }
 
     if (WARN_ON_ONCE(n != segments)) {
         if (virt_to_page(range) == ns->ctrl->discard_page)
             clear_bit_unlock(0, &ns->ctrl->discard_page_busy);
         else
             kfree(range);
         return BLK_STS_IOERR;
     }
 
     memset(cmnd, 0, sizeof(*cmnd));
     cmnd->dsm.opcode = nvme_cmd_dsm;
     cmnd->dsm.nsid = cpu_to_le32(ns->head->ns_id);
     cmnd->dsm.nr = cpu_to_le32(segments - 1);
     cmnd->dsm.attributes = cpu_to_le32(NVME_DSMGMT_AD);
 
     req->special_vec.bv_page = virt_to_page(range);
     req->special_vec.bv_offset = offset_in_page(range);
     req->special_vec.bv_len = alloc_size;
     req->rq_flags |= RQF_SPECIAL_PAYLOAD;
 
     return BLK_STS_OK;
 }
 
 static void nvme_set_ref_tag(struct nvme_ns *ns, struct nvme_command *cmnd,
                   struct request *req)
 {
     u32 upper, lower;
     u64 ref48;
 
     /* both rw and write zeroes share the same reftag format */
     switch (ns->guard_type) {
     case NVME_NVM_NS_16B_GUARD:
         cmnd->rw.reftag = cpu_to_le32(t10_pi_ref_tag(req));
         break;
     case NVME_NVM_NS_64B_GUARD:
         ref48 = ext_pi_ref_tag(req);
         lower = lower_32_bits(ref48);
         upper = upper_32_bits(ref48);
 
         cmnd->rw.reftag = cpu_to_le32(lower);
         cmnd->rw.cdw3 = cpu_to_le32(upper);
         break;
     default:
         break;
     }
 }
 
 static inline blk_status_t nvme_setup_write_zeroes(struct nvme_ns *ns,
         struct request *req, struct nvme_command *cmnd)
 {
     memset(cmnd, 0, sizeof(*cmnd));
 
     if (ns->ctrl->quirks & NVME_QUIRK_DEALLOCATE_ZEROES)
         return nvme_setup_discard(ns, req, cmnd);
 
     cmnd->write_zeroes.opcode = nvme_cmd_write_zeroes;
     cmnd->write_zeroes.nsid = cpu_to_le32(ns->head->ns_id);
     cmnd->write_zeroes.slba =
         cpu_to_le64(nvme_sect_to_lba(ns, blk_rq_pos(req)));
     cmnd->write_zeroes.length =
         cpu_to_le16((blk_rq_bytes(req) >> ns->lba_shift) - 1);
 
     if (nvme_ns_has_pi(ns)) {
         cmnd->write_zeroes.control = cpu_to_le16(NVME_RW_PRINFO_PRACT);
 
         switch (ns->pi_type) {
         case NVME_NS_DPS_PI_TYPE1:
         case NVME_NS_DPS_PI_TYPE2:
             nvme_set_ref_tag(ns, cmnd, req);
             break;
         }
     }
 
     return BLK_STS_OK;
 }
 
 static inline blk_status_t nvme_setup_rw(struct nvme_ns *ns,
         struct request *req, struct nvme_command *cmnd,
         enum nvme_opcode op)
 {
     u16 control = 0;
     u32 dsmgmt = 0;
 
     if (req->cmd_flags & REQ_FUA)
         control |= NVME_RW_FUA;
     if (req->cmd_flags & (REQ_FAILFAST_DEV | REQ_RAHEAD))
         control |= NVME_RW_LR;
 
     if (req->cmd_flags & REQ_RAHEAD)
         dsmgmt |= NVME_RW_DSM_FREQ_PREFETCH;
 
     cmnd->rw.opcode = op;
     cmnd->rw.flags = 0;
     cmnd->rw.nsid = cpu_to_le32(ns->head->ns_id);
     cmnd->rw.cdw2 = 0;
     cmnd->rw.cdw3 = 0;
     cmnd->rw.metadata = 0;
     cmnd->rw.slba = cpu_to_le64(nvme_sect_to_lba(ns, blk_rq_pos(req)));
     cmnd->rw.length = cpu_to_le16((blk_rq_bytes(req) >> ns->lba_shift) - 1);
     cmnd->rw.reftag = 0;
     cmnd->rw.apptag = 0;
     cmnd->rw.appmask = 0;
 
     if (ns->ms) {
         /*
          * If formated with metadata, the block layer always provides a
          * metadata buffer if CONFIG_BLK_DEV_INTEGRITY is enabled.  Else
          * we enable the PRACT bit for protection information or set the
          * namespace capacity to zero to prevent any I/O.
          */
         if (!blk_integrity_rq(req)) {
             if (WARN_ON_ONCE(!nvme_ns_has_pi(ns)))
                 return BLK_STS_NOTSUPP;
             control |= NVME_RW_PRINFO_PRACT;
         }
 
         switch (ns->pi_type) {
         case NVME_NS_DPS_PI_TYPE3:
             control |= NVME_RW_PRINFO_PRCHK_GUARD;
             break;
         case NVME_NS_DPS_PI_TYPE1:
         case NVME_NS_DPS_PI_TYPE2:
             control |= NVME_RW_PRINFO_PRCHK_GUARD |
                     NVME_RW_PRINFO_PRCHK_REF;
             if (op == nvme_cmd_zone_append)
                 control |= NVME_RW_APPEND_PIREMAP;
             nvme_set_ref_tag(ns, cmnd, req);
             break;
         }
     }
 
     cmnd->rw.control = cpu_to_le16(control);
     cmnd->rw.dsmgmt = cpu_to_le32(dsmgmt);
     return 0;
 }
 
 void nvme_cleanup_cmd(struct request *req)
 {
     if (req->rq_flags & RQF_SPECIAL_PAYLOAD) {
         struct nvme_ctrl *ctrl = nvme_req(req)->ctrl;
 
         if (req->special_vec.bv_page == ctrl->discard_page)
             clear_bit_unlock(0, &ctrl->discard_page_busy);
         else
             kfree(bvec_virt(&req->special_vec));
     }
 }
 EXPORT_SYMBOL_GPL(nvme_cleanup_cmd);
 
 blk_status_t nvme_setup_cmd(struct nvme_ns *ns, struct request *req)
 {
     struct nvme_command *cmd = nvme_req(req)->cmd;
     blk_status_t ret = BLK_STS_OK;
 
     if (!(req->rq_flags & RQF_DONTPREP))
         nvme_clear_nvme_request(req);
 
     switch (req_op(req)) {
     case REQ_OP_DRV_IN:
     case REQ_OP_DRV_OUT:
         /* these are setup prior to execution in nvme_init_request() */
         break;
     case REQ_OP_FLUSH:
         nvme_setup_flush(ns, cmd);
         break;
     case REQ_OP_ZONE_RESET_ALL:
     case REQ_OP_ZONE_RESET:
         ret = nvme_setup_zone_mgmt_send(ns, req, cmd, NVME_ZONE_RESET);
         break;
     case REQ_OP_ZONE_OPEN:
         ret = nvme_setup_zone_mgmt_send(ns, req, cmd, NVME_ZONE_OPEN);
         break;
     case REQ_OP_ZONE_CLOSE:
         ret = nvme_setup_zone_mgmt_send(ns, req, cmd, NVME_ZONE_CLOSE);
         break;
     case REQ_OP_ZONE_FINISH:
         ret = nvme_setup_zone_mgmt_send(ns, req, cmd, NVME_ZONE_FINISH);
         break;
     case REQ_OP_WRITE_ZEROES:
         ret = nvme_setup_write_zeroes(ns, req, cmd);
         break;
     case REQ_OP_DISCARD:
         ret = nvme_setup_discard(ns, req, cmd);
         break;
     case REQ_OP_READ:
         ret = nvme_setup_rw(ns, req, cmd, nvme_cmd_read);
         break;
     case REQ_OP_WRITE:
         ret = nvme_setup_rw(ns, req, cmd, nvme_cmd_write);
         break;
     case REQ_OP_ZONE_APPEND:
         ret = nvme_setup_rw(ns, req, cmd, nvme_cmd_zone_append);
         break;
     default:
         WARN_ON_ONCE(1);
         return BLK_STS_IOERR;
     }
 
     cmd->common.command_id = nvme_cid(req);
     trace_nvme_setup_cmd(req, cmd);
     return ret;
 }
 EXPORT_SYMBOL_GPL(nvme_setup_cmd);
 
 /*
  * Return values:
  * 0:  success
  * >0: nvme controller's cqe status response
  * <0: kernel error in lieu of controller response
  */
 static int nvme_execute_rq(struct request *rq, bool at_head)
 {
     blk_status_t status;
 
     status = blk_execute_rq(rq, at_head);
     if (nvme_req(rq)->flags & NVME_REQ_CANCELLED)
         return -EINTR;
     if (nvme_req(rq)->status)
         return nvme_req(rq)->status;
     return blk_status_to_errno(status);
 }
 
 /*
  * Returns 0 on success.  If the result is negative, it's a Linux error code;
  * if the result is positive, it's an NVM Express status code
  */
 int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
         union nvme_result *result, void *buffer, unsigned bufflen,
         int qid, int at_head, blk_mq_req_flags_t flags)
 {
     struct request *req;
     int ret;
 
     if (qid == NVME_QID_ANY)
         req = blk_mq_alloc_request(q, nvme_req_op(cmd), flags);
     else
         req = blk_mq_alloc_request_hctx(q, nvme_req_op(cmd), flags,
                         qid - 1);
 
     if (IS_ERR(req))
         return PTR_ERR(req);
     nvme_init_request(req, cmd);
 
     if (buffer && bufflen) {
         ret = blk_rq_map_kern(q, req, buffer, bufflen, GFP_KERNEL);
         if (ret)
             goto out;
     }
 
     req->rq_flags |= RQF_QUIET;
     ret = nvme_execute_rq(req, at_head);
     if (result && ret >= 0)
         *result = nvme_req(req)->result;
  out:
     blk_mq_free_request(req);
     return ret;
 }
 EXPORT_SYMBOL_GPL(__nvme_submit_sync_cmd);
 
 int nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
         void *buffer, unsigned bufflen)
 {
     return __nvme_submit_sync_cmd(q, cmd, NULL, buffer, bufflen,
             NVME_QID_ANY, 0, 0);
 }
 EXPORT_SYMBOL_GPL(nvme_submit_sync_cmd);
 
 static u32 nvme_known_admin_effects(u8 opcode)
 {
     switch (opcode) {
     case nvme_admin_format_nvm:
         return NVME_CMD_EFFECTS_LBCC | NVME_CMD_EFFECTS_NCC |
             NVME_CMD_EFFECTS_CSE_MASK;
     case nvme_admin_sanitize_nvm:
         return NVME_CMD_EFFECTS_LBCC | NVME_CMD_EFFECTS_CSE_MASK;
     default:
         break;
     }
     return 0;
 }
 
 u32 nvme_command_effects(struct nvme_ctrl *ctrl, struct nvme_ns *ns, u8 opcode)
 {
     u32 effects = 0;
 
     if (ns) {
         if (ns->head->effects)
             effects = le32_to_cpu(ns->head->effects->iocs[opcode]);
         if (effects & ~(NVME_CMD_EFFECTS_CSUPP | NVME_CMD_EFFECTS_LBCC))
             dev_warn_once(ctrl->device,
                 "IO command:%02x has unhandled effects:%08x\n",
                 opcode, effects);
         return 0;
     }
 
     if (ctrl->effects)
         effects = le32_to_cpu(ctrl->effects->acs[opcode]);
     effects |= nvme_known_admin_effects(opcode);
 
     return effects;
 }
 EXPORT_SYMBOL_NS_GPL(nvme_command_effects, NVME_TARGET_PASSTHRU);
 
 static u32 nvme_passthru_start(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
                    u8 opcode)
 {
     u32 effects = nvme_command_effects(ctrl, ns, opcode);
 
     /*
      * For simplicity, IO to all namespaces is quiesced even if the command
      * effects say only one namespace is affected.
      */
     if (effects & NVME_CMD_EFFECTS_CSE_MASK) {
         mutex_lock(&ctrl->scan_lock);
         mutex_lock(&ctrl->subsys->lock);
         nvme_mpath_start_freeze(ctrl->subsys);
         nvme_mpath_wait_freeze(ctrl->subsys);
         nvme_start_freeze(ctrl);
         nvme_wait_freeze(ctrl);
     }
     return effects;
 }
 
 static void nvme_passthru_end(struct nvme_ctrl *ctrl, u32 effects,
                   struct nvme_command *cmd, int status)
 {
     if (effects & NVME_CMD_EFFECTS_CSE_MASK) {
         nvme_unfreeze(ctrl);
         nvme_mpath_unfreeze(ctrl->subsys);
         mutex_unlock(&ctrl->subsys->lock);
         nvme_remove_invalid_namespaces(ctrl, NVME_NSID_ALL);
         mutex_unlock(&ctrl->scan_lock);
     }
     if (effects & NVME_CMD_EFFECTS_CCC)
         nvme_init_ctrl_finish(ctrl);
     if (effects & (NVME_CMD_EFFECTS_NIC | NVME_CMD_EFFECTS_NCC)) {
         nvme_queue_scan(ctrl);
         flush_work(&ctrl->scan_work);
     }
 
     switch (cmd->common.opcode) {
     case nvme_admin_set_features:
         switch (le32_to_cpu(cmd->common.cdw10) & 0xFF) {
         case NVME_FEAT_KATO:
             /*
              * Keep alive commands interval on the host should be
              * updated when KATO is modified by Set Features
              * commands.
              */
             if (!status)
                 nvme_update_keep_alive(ctrl, cmd);
             break;
         default:
             break;
         }
         break;
     default:
         break;
     }
 }
 
 int nvme_execute_passthru_rq(struct request *rq)
 {
     struct nvme_command *cmd = nvme_req(rq)->cmd;
     struct nvme_ctrl *ctrl = nvme_req(rq)->ctrl;
     struct nvme_ns *ns = rq->q->queuedata;
     u32 effects;
     int  ret;
 
     effects = nvme_passthru_start(ctrl, ns, cmd->common.opcode);
     ret = nvme_execute_rq(rq, false);
     if (effects) /* nothing to be done for zero cmd effects */
         nvme_passthru_end(ctrl, effects, cmd, ret);
 
     return ret;
 }
 EXPORT_SYMBOL_NS_GPL(nvme_execute_passthru_rq, NVME_TARGET_PASSTHRU);
 
 /*
  * Recommended frequency for KATO commands per NVMe 1.4 section 7.12.1:
  * 
  *   The host should send Keep Alive commands at half of the Keep Alive Timeout
  *   accounting for transport roundtrip times [..].
  */
 static void nvme_queue_keep_alive_work(struct nvme_ctrl *ctrl)
 {
     queue_delayed_work(nvme_wq, &ctrl->ka_work, ctrl->kato * HZ / 2);
 }
 
 static void nvme_keep_alive_end_io(struct request *rq, blk_status_t status)
 {
     struct nvme_ctrl *ctrl = rq->end_io_data;
     unsigned long flags;
     bool startka = false;
 
     blk_mq_free_request(rq);
 
     if (status) {
         dev_err(ctrl->device,
             "failed nvme_keep_alive_end_io error=%d\n",
                 status);
         return;
     }
 
     ctrl->comp_seen = false;
     spin_lock_irqsave(&ctrl->lock, flags);
     if (ctrl->state == NVME_CTRL_LIVE ||
         ctrl->state == NVME_CTRL_CONNECTING)
         startka = true;
     spin_unlock_irqrestore(&ctrl->lock, flags);
     if (startka)
         nvme_queue_keep_alive_work(ctrl);
 }
 
 static void nvme_keep_alive_work(struct work_struct *work)
 {
     struct nvme_ctrl *ctrl = container_of(to_delayed_work(work),
             struct nvme_ctrl, ka_work);
     bool comp_seen = ctrl->comp_seen;
     struct request *rq;
 
     if ((ctrl->ctratt & NVME_CTRL_ATTR_TBKAS) && comp_seen) {
         dev_dbg(ctrl->device,
             "reschedule traffic based keep-alive timer\n");
         ctrl->comp_seen = false;
         nvme_queue_keep_alive_work(ctrl);
         return;
     }
 
     rq = blk_mq_alloc_request(ctrl->admin_q, nvme_req_op(&ctrl->ka_cmd),
                   BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT);
     if (IS_ERR(rq)) {
         /* allocation failure, reset the controller */
         dev_err(ctrl->device, "keep-alive failed: %ld\n", PTR_ERR(rq));
         nvme_reset_ctrl(ctrl);
         return;
     }
     nvme_init_request(rq, &ctrl->ka_cmd);
 
     rq->timeout = ctrl->kato * HZ;
     rq->end_io = nvme_keep_alive_end_io;
     rq->end_io_data = ctrl;
     rq->rq_flags |= RQF_QUIET;
     blk_execute_rq_nowait(rq, false);
 }
 
 static void nvme_start_keep_alive(struct nvme_ctrl *ctrl)
 {
     if (unlikely(ctrl->kato == 0))
         return;
 
     nvme_queue_keep_alive_work(ctrl);
 }
 
 void nvme_stop_keep_alive(struct nvme_ctrl *ctrl)
 {
     if (unlikely(ctrl->kato == 0))
         return;
 
     cancel_delayed_work_sync(&ctrl->ka_work);
 }
 EXPORT_SYMBOL_GPL(nvme_stop_keep_alive);
 
 static void nvme_update_keep_alive(struct nvme_ctrl *ctrl,
                    struct nvme_command *cmd)
 {
     unsigned int new_kato =
         DIV_ROUND_UP(le32_to_cpu(cmd->common.cdw11), 1000);
 
     dev_info(ctrl->device,
          "keep alive interval updated from %u ms to %u ms\n",
          ctrl->kato * 1000 / 2, new_kato * 1000 / 2);
 
     nvme_stop_keep_alive(ctrl);
     ctrl->kato = new_kato;
     nvme_start_keep_alive(ctrl);
 }
 
 /*
  * In NVMe 1.0 the CNS field was just a binary controller or namespace
  * flag, thus sending any new CNS opcodes has a big chance of not working.
  * Qemu unfortunately had that bug after reporting a 1.1 version compliance
  * (but not for any later version).
  */
 static bool nvme_ctrl_limited_cns(struct nvme_ctrl *ctrl)
 {
     if (ctrl->quirks & NVME_QUIRK_IDENTIFY_CNS)
         return ctrl->vs < NVME_VS(1, 2, 0);
     return ctrl->vs < NVME_VS(1, 1, 0);
 }
 
 static int nvme_identify_ctrl(struct nvme_ctrl *dev, struct nvme_id_ctrl **id)
 {
     struct nvme_command c = { };
     int error;
 
     /* gcc-4.4.4 (at least) has issues with initializers and anon unions */
     c.identify.opcode = nvme_admin_identify;
     c.identify.cns = NVME_ID_CNS_CTRL;
 
     *id = kmalloc(sizeof(struct nvme_id_ctrl), GFP_KERNEL);
     if (!*id)
         return -ENOMEM;
 
     error = nvme_submit_sync_cmd(dev->admin_q, &c, *id,
             sizeof(struct nvme_id_ctrl));
     if (error)
         kfree(*id);
     return error;
 }
 
 static int nvme_process_ns_desc(struct nvme_ctrl *ctrl, struct nvme_ns_ids *ids,
         struct nvme_ns_id_desc *cur, bool *csi_seen)
 {
     const char *warn_str = "ctrl returned bogus length:";
     void *data = cur;
 
     switch (cur->nidt) {
     case NVME_NIDT_EUI64:
         if (cur->nidl != NVME_NIDT_EUI64_LEN) {
             dev_warn(ctrl->device, "%s %d for NVME_NIDT_EUI64\n",
                  warn_str, cur->nidl);
             return -1;
         }
         if (ctrl->quirks & NVME_QUIRK_BOGUS_NID)
             return NVME_NIDT_EUI64_LEN;
         memcpy(ids->eui64, data + sizeof(*cur), NVME_NIDT_EUI64_LEN);
         return NVME_NIDT_EUI64_LEN;
     case NVME_NIDT_NGUID:
         if (cur->nidl != NVME_NIDT_NGUID_LEN) {
             dev_warn(ctrl->device, "%s %d for NVME_NIDT_NGUID\n",
                  warn_str, cur->nidl);
             return -1;
         }
         if (ctrl->quirks & NVME_QUIRK_BOGUS_NID)
             return NVME_NIDT_NGUID_LEN;
         memcpy(ids->nguid, data + sizeof(*cur), NVME_NIDT_NGUID_LEN);
         return NVME_NIDT_NGUID_LEN;
     case NVME_NIDT_UUID:
         if (cur->nidl != NVME_NIDT_UUID_LEN) {
             dev_warn(ctrl->device, "%s %d for NVME_NIDT_UUID\n",
                  warn_str, cur->nidl);
             return -1;
         }
         if (ctrl->quirks & NVME_QUIRK_BOGUS_NID)
             return NVME_NIDT_UUID_LEN;
         uuid_copy(&ids->uuid, data + sizeof(*cur));
         return NVME_NIDT_UUID_LEN;
     case NVME_NIDT_CSI:
         if (cur->nidl != NVME_NIDT_CSI_LEN) {
             dev_warn(ctrl->device, "%s %d for NVME_NIDT_CSI\n",
                  warn_str, cur->nidl);
             return -1;
         }
         memcpy(&ids->csi, data + sizeof(*cur), NVME_NIDT_CSI_LEN);
         *csi_seen = true;
         return NVME_NIDT_CSI_LEN;
     default:
         /* Skip unknown types */
         return cur->nidl;
     }
 }
 
 static int nvme_identify_ns_descs(struct nvme_ctrl *ctrl,
         struct nvme_ns_info *info)
 {
     struct nvme_command c = { };
     bool csi_seen = false;
     int status, pos, len;
     void *data;
 
     if (ctrl->vs < NVME_VS(1, 3, 0) && !nvme_multi_css(ctrl))
         return 0;
     if (ctrl->quirks & NVME_QUIRK_NO_NS_DESC_LIST)
         return 0;
 
     c.identify.opcode = nvme_admin_identify;
     c.identify.nsid = cpu_to_le32(info->nsid);
     c.identify.cns = NVME_ID_CNS_NS_DESC_LIST;
 
     data = kzalloc(NVME_IDENTIFY_DATA_SIZE, GFP_KERNEL);
     if (!data)
         return -ENOMEM;
 
     status = nvme_submit_sync_cmd(ctrl->admin_q, &c, data,
                       NVME_IDENTIFY_DATA_SIZE);
     if (status) {
         dev_warn(ctrl->device,
             "Identify Descriptors failed (nsid=%u, status=0x%x)\n",
             info->nsid, status);
         goto free_data;
     }
 
     for (pos = 0; pos < NVME_IDENTIFY_DATA_SIZE; pos += len) {
         struct nvme_ns_id_desc *cur = data + pos;
 
         if (cur->nidl == 0)
             break;
 
         len = nvme_process_ns_desc(ctrl, &info->ids, cur, &csi_seen);
         if (len < 0)
             break;
 
         len += sizeof(*cur);
     }
 
     if (nvme_multi_css(ctrl) && !csi_seen) {
         dev_warn(ctrl->device, "Command set not reported for nsid:%d\n",
              info->nsid);
         status = -EINVAL;
     }
 
 free_data:
     kfree(data);
     return status;
 }
 
 static int nvme_identify_ns(struct nvme_ctrl *ctrl, unsigned nsid,
             struct nvme_id_ns **id)
 {
     struct nvme_command c = { };
     int error;
 
     /* gcc-4.4.4 (at least) has issues with initializers and anon unions */
     c.identify.opcode = nvme_admin_identify;
     c.identify.nsid = cpu_to_le32(nsid);
     c.identify.cns = NVME_ID_CNS_NS;
 
     *id = kmalloc(sizeof(**id), GFP_KERNEL);
     if (!*id)
         return -ENOMEM;
 
     error = nvme_submit_sync_cmd(ctrl->admin_q, &c, *id, sizeof(**id));
     if (error) {
         dev_warn(ctrl->device, "Identify namespace failed (%d)\n", error);
         goto out_free_id;
     }
 
     error = NVME_SC_INVALID_NS | NVME_SC_DNR;
     if ((*id)->ncap == 0) /* namespace not allocated or attached */
         goto out_free_id;
     return 0;
 
 out_free_id:
     kfree(*id);
     return error;
 }
 
 static int nvme_ns_info_from_identify(struct nvme_ctrl *ctrl,
         struct nvme_ns_info *info)
 {
     struct nvme_ns_ids *ids = &info->ids;
     struct nvme_id_ns *id;
     int ret;
 
     ret = nvme_identify_ns(ctrl, info->nsid, &id);
     if (ret)
         return ret;
     info->anagrpid = id->anagrpid;
     info->is_shared = id->nmic & NVME_NS_NMIC_SHARED;
     info->is_readonly = id->nsattr & NVME_NS_ATTR_RO;
     info->is_ready = true;
     if (ctrl->quirks & NVME_QUIRK_BOGUS_NID) {
         dev_info(ctrl->device,
              "Ignoring bogus Namespace Identifiers\n");
     } else {
         if (ctrl->vs >= NVME_VS(1, 1, 0) &&
             !memchr_inv(ids->eui64, 0, sizeof(ids->eui64)))
             memcpy(ids->eui64, id->eui64, sizeof(ids->eui64));
         if (ctrl->vs >= NVME_VS(1, 2, 0) &&
             !memchr_inv(ids->nguid, 0, sizeof(ids->nguid)))
             memcpy(ids->nguid, id->nguid, sizeof(ids->nguid));
     }
     kfree(id);
     return 0;
 }
 
 static int nvme_ns_info_from_id_cs_indep(struct nvme_ctrl *ctrl,
         struct nvme_ns_info *info)
 {
     struct nvme_id_ns_cs_indep *id;
     struct nvme_command c = {
         .identify.opcode    = nvme_admin_identify,
         .identify.nsid      = cpu_to_le32(info->nsid),
         .identify.cns       = NVME_ID_CNS_NS_CS_INDEP,
     };
     int ret;
 
     id = kmalloc(sizeof(*id), GFP_KERNEL);
     if (!id)
         return -ENOMEM;
 
     ret = nvme_submit_sync_cmd(ctrl->admin_q, &c, id, sizeof(*id));
     if (!ret) {
         info->anagrpid = id->anagrpid;
         info->is_shared = id->nmic & NVME_NS_NMIC_SHARED;
         info->is_readonly = id->nsattr & NVME_NS_ATTR_RO;
         info->is_ready = id->nstat & NVME_NSTAT_NRDY;
     }
     kfree(id);
     return ret;
 }
 
 static int nvme_features(struct nvme_ctrl *dev, u8 op, unsigned int fid,
         unsigned int dword11, void *buffer, size_t buflen, u32 *result)
 {
     union nvme_result res = { 0 };
     struct nvme_command c = { };
     int ret;
 
     c.features.opcode = op;
     c.features.fid = cpu_to_le32(fid);
     c.features.dword11 = cpu_to_le32(dword11);
 
     ret = __nvme_submit_sync_cmd(dev->admin_q, &c, &res,
             buffer, buflen, NVME_QID_ANY, 0, 0);
     if (ret >= 0 && result)
         *result = le32_to_cpu(res.u32);
     return ret;
 }
 
 int nvme_set_features(struct nvme_ctrl *dev, unsigned int fid,
               unsigned int dword11, void *buffer, size_t buflen,
               u32 *result)
 {
     return nvme_features(dev, nvme_admin_set_features, fid, dword11, buffer,
                  buflen, result);
 }
 EXPORT_SYMBOL_GPL(nvme_set_features);
 
 int nvme_get_features(struct nvme_ctrl *dev, unsigned int fid,
               unsigned int dword11, void *buffer, size_t buflen,
               u32 *result)
 {
     return nvme_features(dev, nvme_admin_get_features, fid, dword11, buffer,
                  buflen, result);
 }
 EXPORT_SYMBOL_GPL(nvme_get_features);
 
 int nvme_set_queue_count(struct nvme_ctrl *ctrl, int *count)
 {
     u32 q_count = (*count - 1) | ((*count - 1) << 16);
     u32 result;
     int status, nr_io_queues;
 
     status = nvme_set_features(ctrl, NVME_FEAT_NUM_QUEUES, q_count, NULL, 0,
             &result);
     if (status < 0)
         return status;
 
     /*
      * Degraded controllers might return an error when setting the queue
      * count.  We still want to be able to bring them online and offer
      * access to the admin queue, as that might be only way to fix them up.
      */
     if (status > 0) {
         dev_err(ctrl->device, "Could not set queue count (%d)\n", status);
         *count = 0;
     } else {
         nr_io_queues = min(result & 0xffff, result >> 16) + 1;
         *count = min(*count, nr_io_queues);
     }
 
     return 0;
 }
 EXPORT_SYMBOL_GPL(nvme_set_queue_count);
 
 #define NVME_AEN_SUPPORTED \
     (NVME_AEN_CFG_NS_ATTR | NVME_AEN_CFG_FW_ACT | \
      NVME_AEN_CFG_ANA_CHANGE | NVME_AEN_CFG_DISC_CHANGE)
 
 static void nvme_enable_aen(struct nvme_ctrl *ctrl)
 {
     u32 result, supported_aens = ctrl->oaes & NVME_AEN_SUPPORTED;
     int status;
 
     if (!supported_aens)
         return;
 
     status = nvme_set_features(ctrl, NVME_FEAT_ASYNC_EVENT, supported_aens,
             NULL, 0, &result);
     if (status)
         dev_warn(ctrl->device, "Failed to configure AEN (cfg %x)\n",
              supported_aens);
 
     queue_work(nvme_wq, &ctrl->async_event_work);
 }
 
 static int nvme_ns_open(struct nvme_ns *ns)
 {
 
     /* should never be called due to GENHD_FL_HIDDEN */
     if (WARN_ON_ONCE(nvme_ns_head_multipath(ns->head)))
         goto fail;
     if (!nvme_get_ns(ns))
         goto fail;
     if (!try_module_get(ns->ctrl->ops->module))
         goto fail_put_ns;
 
     return 0;
 
 fail_put_ns:
     nvme_put_ns(ns);
 fail:
     return -ENXIO;
 }
 
 static void nvme_ns_release(struct nvme_ns *ns)
 {
 
     module_put(ns->ctrl->ops->module);
     nvme_put_ns(ns);
 }
 
 static int nvme_open(struct block_device *bdev, fmode_t mode)
 {
     return nvme_ns_open(bdev->bd_disk->private_data);
 }
 
 static void nvme_release(struct gendisk *disk, fmode_t mode)
 {
     nvme_ns_release(disk->private_data);
 }
 
 int nvme_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 {
     /* some standard values */
     geo->heads = 1 << 6;
     geo->sectors = 1 << 5;
     geo->cylinders = get_capacity(bdev->bd_disk) >> 11;
     return 0;
 }
 
 #ifdef CONFIG_BLK_DEV_INTEGRITY
 static void nvme_init_integrity(struct gendisk *disk, struct nvme_ns *ns,
                 u32 max_integrity_segments)
 {
     struct blk_integrity integrity = { };
 
     switch (ns->pi_type) {
     case NVME_NS_DPS_PI_TYPE3:
         switch (ns->guard_type) {
         case NVME_NVM_NS_16B_GUARD:
             integrity.profile = &t10_pi_type3_crc;
             integrity.tag_size = sizeof(u16) + sizeof(u32);
             integrity.flags |= BLK_INTEGRITY_DEVICE_CAPABLE;
             break;
         case NVME_NVM_NS_64B_GUARD:
             integrity.profile = &ext_pi_type3_crc64;
             integrity.tag_size = sizeof(u16) + 6;
             integrity.flags |= BLK_INTEGRITY_DEVICE_CAPABLE;
             break;
         default:
             integrity.profile = NULL;
             break;
         }
         break;
     case NVME_NS_DPS_PI_TYPE1:
     case NVME_NS_DPS_PI_TYPE2:
         switch (ns->guard_type) {
         case NVME_NVM_NS_16B_GUARD:
             integrity.profile = &t10_pi_type1_crc;
             integrity.tag_size = sizeof(u16);
             integrity.flags |= BLK_INTEGRITY_DEVICE_CAPABLE;
             break;
         case NVME_NVM_NS_64B_GUARD:
             integrity.profile = &ext_pi_type1_crc64;
             integrity.tag_size = sizeof(u16);
             integrity.flags |= BLK_INTEGRITY_DEVICE_CAPABLE;
             break;
         default:
             integrity.profile = NULL;
             break;
         }
         break;
     default:
         integrity.profile = NULL;
         break;
     }
 
     integrity.tuple_size = ns->ms;
     blk_integrity_register(disk, &integrity);
     blk_queue_max_integrity_segments(disk->queue, max_integrity_segments);
 }
 #else
 static void nvme_init_integrity(struct gendisk *disk, struct nvme_ns *ns,
                 u32 max_integrity_segments)
 {
 }
 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 
 static void nvme_config_discard(struct gendisk *disk, struct nvme_ns *ns)
 {
     struct nvme_ctrl *ctrl = ns->ctrl;
     struct request_queue *queue = disk->queue;
     u32 size = queue_logical_block_size(queue);
 
     if (ctrl->max_discard_sectors == 0) {
         blk_queue_max_discard_sectors(queue, 0);
         return;
     }
 
     BUILD_BUG_ON(PAGE_SIZE / sizeof(struct nvme_dsm_range) <
             NVME_DSM_MAX_RANGES);
 
     queue->limits.discard_granularity = size;
 
     /* If discard is already enabled, don't reset queue limits */
     if (queue->limits.max_discard_sectors)
         return;
 
     if (ctrl->dmrsl && ctrl->dmrsl <= nvme_sect_to_lba(ns, UINT_MAX))
         ctrl->max_discard_sectors = nvme_lba_to_sect(ns, ctrl->dmrsl);
 
     blk_queue_max_discard_sectors(queue, ctrl->max_discard_sectors);
     blk_queue_max_discard_segments(queue, ctrl->max_discard_segments);
 
     if (ctrl->quirks & NVME_QUIRK_DEALLOCATE_ZEROES)
         blk_queue_max_write_zeroes_sectors(queue, UINT_MAX);
 }
 
 static bool nvme_ns_ids_equal(struct nvme_ns_ids *a, struct nvme_ns_ids *b)
 {
     return uuid_equal(&a->uuid, &b->uuid) &&
         memcmp(&a->nguid, &b->nguid, sizeof(a->nguid)) == 0 &&
         memcmp(&a->eui64, &b->eui64, sizeof(a->eui64)) == 0 &&
         a->csi == b->csi;
 }
 
 static int nvme_init_ms(struct nvme_ns *ns, struct nvme_id_ns *id)
 {
     bool first = id->dps & NVME_NS_DPS_PI_FIRST;
     unsigned lbaf = nvme_lbaf_index(id->flbas);
     struct nvme_ctrl *ctrl = ns->ctrl;
     struct nvme_command c = { };
     struct nvme_id_ns_nvm *nvm;
     int ret = 0;
     u32 elbaf;
 
     ns->pi_size = 0;
     ns->ms = le16_to_cpu(id->lbaf[lbaf].ms);
     if (!(ctrl->ctratt & NVME_CTRL_ATTR_ELBAS)) {
         ns->pi_size = sizeof(struct t10_pi_tuple);
         ns->guard_type = NVME_NVM_NS_16B_GUARD;
         goto set_pi;
     }
 
     nvm = kzalloc(sizeof(*nvm), GFP_KERNEL);
     if (!nvm)
         return -ENOMEM;
 
     c.identify.opcode = nvme_admin_identify;
     c.identify.nsid = cpu_to_le32(ns->head->ns_id);
     c.identify.cns = NVME_ID_CNS_CS_NS;
     c.identify.csi = NVME_CSI_NVM;
 
     ret = nvme_submit_sync_cmd(ns->ctrl->admin_q, &c, nvm, sizeof(*nvm));
     if (ret)
         goto free_data;
 
     elbaf = le32_to_cpu(nvm->elbaf[lbaf]);
 
     /* no support for storage tag formats right now */
     if (nvme_elbaf_sts(elbaf))
         goto free_data;
 
     ns->guard_type = nvme_elbaf_guard_type(elbaf);
     switch (ns->guard_type) {
     case NVME_NVM_NS_64B_GUARD:
         ns->pi_size = sizeof(struct crc64_pi_tuple);
         break;
     case NVME_NVM_NS_16B_GUARD:
         ns->pi_size = sizeof(struct t10_pi_tuple);
         break;
     default:
         break;
     }
 
 free_data:
     kfree(nvm);
 set_pi:
     if (ns->pi_size && (first || ns->ms == ns->pi_size))
         ns->pi_type = id->dps & NVME_NS_DPS_PI_MASK;
     else
         ns->pi_type = 0;
 
     return ret;
 }
 
 static void nvme_configure_metadata(struct nvme_ns *ns, struct nvme_id_ns *id)
 {
     struct nvme_ctrl *ctrl = ns->ctrl;
 
     if (nvme_init_ms(ns, id))
         return;
 
     ns->features &= ~(NVME_NS_METADATA_SUPPORTED | NVME_NS_EXT_LBAS);
     if (!ns->ms || !(ctrl->ops->flags & NVME_F_METADATA_SUPPORTED))
         return;
 
     if (ctrl->ops->flags & NVME_F_FABRICS) {
         /*
          * The NVMe over Fabrics specification only supports metadata as
          * part of the extended data LBA.  We rely on HCA/HBA support to
          * remap the separate metadata buffer from the block layer.
          */
         if (WARN_ON_ONCE(!(id->flbas & NVME_NS_FLBAS_META_EXT)))
             return;
 
         ns->features |= NVME_NS_EXT_LBAS;
 
         /*
          * The current fabrics transport drivers support namespace
          * metadata formats only if nvme_ns_has_pi() returns true.
          * Suppress support for all other formats so the namespace will
          * have a 0 capacity and not be usable through the block stack.
          *
          * Note, this check will need to be modified if any drivers
          * gain the ability to use other metadata formats.
          */
         if (ctrl->max_integrity_segments && nvme_ns_has_pi(ns))
             ns->features |= NVME_NS_METADATA_SUPPORTED;
     } else {
         /*
          * For PCIe controllers, we can't easily remap the separate
          * metadata buffer from the block layer and thus require a
          * separate metadata buffer for block layer metadata/PI support.
          * We allow extended LBAs for the passthrough interface, though.
          */
         if (id->flbas & NVME_NS_FLBAS_META_EXT)
             ns->features |= NVME_NS_EXT_LBAS;
         else
             ns->features |= NVME_NS_METADATA_SUPPORTED;
     }
 }
 
 static void nvme_set_queue_limits(struct nvme_ctrl *ctrl,
         struct request_queue *q)
 {
     bool vwc = ctrl->vwc & NVME_CTRL_VWC_PRESENT;
 
     if (ctrl->max_hw_sectors) {
         u32 max_segments =
             (ctrl->max_hw_sectors / (NVME_CTRL_PAGE_SIZE >> 9)) + 1;
 
         max_segments = min_not_zero(max_segments, ctrl->max_segments);
         blk_queue_max_hw_sectors(q, ctrl->max_hw_sectors);
         blk_queue_max_segments(q, min_t(u32, max_segments, USHRT_MAX));
     }
     blk_queue_virt_boundary(q, NVME_CTRL_PAGE_SIZE - 1);
     blk_queue_dma_alignment(q, 3);
     blk_queue_write_cache(q, vwc, vwc);
 }
 
 static void nvme_update_disk_info(struct gendisk *disk,
         struct nvme_ns *ns, struct nvme_id_ns *id)
 {
     sector_t capacity = nvme_lba_to_sect(ns, le64_to_cpu(id->nsze));
     unsigned short bs = 1 << ns->lba_shift;
     u32 atomic_bs, phys_bs, io_opt = 0;
 
     /*
      * The block layer can't support LBA sizes larger than the page size
      * yet, so catch this early and don't allow block I/O.
      */
     if (ns->lba_shift > PAGE_SHIFT) {
         capacity = 0;
         bs = (1 << 9);
     }
 
     blk_integrity_unregister(disk);
 
     atomic_bs = phys_bs = bs;
     if (id->nabo == 0) {
         /*
          * Bit 1 indicates whether NAWUPF is defined for this namespace
          * and whether it should be used instead of AWUPF. If NAWUPF ==
          * 0 then AWUPF must be used instead.
          */
         if (id->nsfeat & NVME_NS_FEAT_ATOMICS && id->nawupf)
             atomic_bs = (1 + le16_to_cpu(id->nawupf)) * bs;
         else
             atomic_bs = (1 + ns->ctrl->subsys->awupf) * bs;
     }
 
     if (id->nsfeat & NVME_NS_FEAT_IO_OPT) {
         /* NPWG = Namespace Preferred Write Granularity */
         phys_bs = bs * (1 + le16_to_cpu(id->npwg));
         /* NOWS = Namespace Optimal Write Size */
         io_opt = bs * (1 + le16_to_cpu(id->nows));
     }
 
     blk_queue_logical_block_size(disk->queue, bs);
     /*
      * Linux filesystems assume writing a single physical block is
      * an atomic operation. Hence limit the physical block size to the
      * value of the Atomic Write Unit Power Fail parameter.
      */
     blk_queue_physical_block_size(disk->queue, min(phys_bs, atomic_bs));
     blk_queue_io_min(disk->queue, phys_bs);
     blk_queue_io_opt(disk->queue, io_opt);
 
     /*
      * Register a metadata profile for PI, or the plain non-integrity NVMe
      * metadata masquerading as Type 0 if supported, otherwise reject block
      * I/O to namespaces with metadata except when the namespace supports
      * PI, as it can strip/insert in that case.
      */
     if (ns->ms) {
         if (IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY) &&
             (ns->features & NVME_NS_METADATA_SUPPORTED))
             nvme_init_integrity(disk, ns,
                         ns->ctrl->max_integrity_segments);
         else if (!nvme_ns_has_pi(ns))
             capacity = 0;
     }
 
     set_capacity_and_notify(disk, capacity);
 
     nvme_config_discard(disk, ns);
     blk_queue_max_write_zeroes_sectors(disk->queue,
                        ns->ctrl->max_zeroes_sectors);
 }
 
 static bool nvme_ns_is_readonly(struct nvme_ns *ns, struct nvme_ns_info *info)
 {
     return info->is_readonly || test_bit(NVME_NS_FORCE_RO, &ns->flags);
 }
 
 static inline bool nvme_first_scan(struct gendisk *disk)
 {
     /* nvme_alloc_ns() scans the disk prior to adding it */
     return !disk_live(disk);
 }
 
 static void nvme_set_chunk_sectors(struct nvme_ns *ns, struct nvme_id_ns *id)
 {
     struct nvme_ctrl *ctrl = ns->ctrl;
     u32 iob;
 
     if ((ctrl->quirks & NVME_QUIRK_STRIPE_SIZE) &&
         is_power_of_2(ctrl->max_hw_sectors))
         iob = ctrl->max_hw_sectors;
     else
         iob = nvme_lba_to_sect(ns, le16_to_cpu(id->noiob));
 
     if (!iob)
         return;
 
     if (!is_power_of_2(iob)) {
         if (nvme_first_scan(ns->disk))
             pr_warn("%s: ignoring unaligned IO boundary:%u\n",
                 ns->disk->disk_name, iob);
         return;
     }
 
     if (blk_queue_is_zoned(ns->disk->queue)) {
         if (nvme_first_scan(ns->disk))
             pr_warn("%s: ignoring zoned namespace IO boundary\n",
                 ns->disk->disk_name);
         return;
     }
 
     blk_queue_chunk_sectors(ns->queue, iob);
 }
 
 static int nvme_update_ns_info_generic(struct nvme_ns *ns,
         struct nvme_ns_info *info)
 {
     blk_mq_freeze_queue(ns->disk->queue);
     nvme_set_queue_limits(ns->ctrl, ns->queue);
     set_disk_ro(ns->disk, nvme_ns_is_readonly(ns, info));
     blk_mq_unfreeze_queue(ns->disk->queue);
 
     if (nvme_ns_head_multipath(ns->head)) {
         blk_mq_freeze_queue(ns->head->disk->queue);
         set_disk_ro(ns->head->disk, nvme_ns_is_readonly(ns, info));
         nvme_mpath_revalidate_paths(ns);
         blk_stack_limits(&ns->head->disk->queue->limits,
                  &ns->queue->limits, 0);
         ns->head->disk->flags |= GENHD_FL_HIDDEN;
         blk_mq_unfreeze_queue(ns->head->disk->queue);
     }
 
     /* Hide the block-interface for these devices */
     ns->disk->flags |= GENHD_FL_HIDDEN;
     set_bit(NVME_NS_READY, &ns->flags);
 
     return 0;
 }
 
 static int nvme_update_ns_info_block(struct nvme_ns *ns,
         struct nvme_ns_info *info)
 {
     struct nvme_id_ns *id;
     unsigned lbaf;
     int ret;
 
     ret = nvme_identify_ns(ns->ctrl, info->nsid, &id);
     if (ret)
         return ret;
 
     blk_mq_freeze_queue(ns->disk->queue);
     lbaf = nvme_lbaf_index(id->flbas);
     ns->lba_shift = id->lbaf[lbaf].ds;
     nvme_set_queue_limits(ns->ctrl, ns->queue);
 
     nvme_configure_metadata(ns, id);
     nvme_set_chunk_sectors(ns, id);
     nvme_update_disk_info(ns->disk, ns, id);
 
     if (ns->head->ids.csi == NVME_CSI_ZNS) {
         ret = nvme_update_zone_info(ns, lbaf);
         if (ret) {
             blk_mq_unfreeze_queue(ns->disk->queue);
             goto out;
         }
     }
 
     set_disk_ro(ns->disk, nvme_ns_is_readonly(ns, info));
     set_bit(NVME_NS_READY, &ns->flags);
     blk_mq_unfreeze_queue(ns->disk->queue);
 
     if (blk_queue_is_zoned(ns->queue)) {
         ret = nvme_revalidate_zones(ns);
         if (ret && !nvme_first_scan(ns->disk))
             goto out;
     }
 
     if (nvme_ns_head_multipath(ns->head)) {
         blk_mq_freeze_queue(ns->head->disk->queue);
         nvme_update_disk_info(ns->head->disk, ns, id);
         set_disk_ro(ns->head->disk, nvme_ns_is_readonly(ns, info));
         nvme_mpath_revalidate_paths(ns);
         blk_stack_limits(&ns->head->disk->queue->limits,
                  &ns->queue->limits, 0);
         disk_update_readahead(ns->head->disk);
         blk_mq_unfreeze_queue(ns->head->disk->queue);
     }
 
     ret = 0;
 out:
     /*
      * If probing fails due an unsupported feature, hide the block device,
      * but still allow other access.
      */
     if (ret == -ENODEV) {
         ns->disk->flags |= GENHD_FL_HIDDEN;
         set_bit(NVME_NS_READY, &ns->flags);
         ret = 0;
     }
     kfree(id);
     return ret;
 }
 
 static int nvme_update_ns_info(struct nvme_ns *ns, struct nvme_ns_info *info)
 {
     switch (info->ids.csi) {
     case NVME_CSI_ZNS:
         if (!IS_ENABLED(CONFIG_BLK_DEV_ZONED)) {
             dev_info(ns->ctrl->device,
     "block device for nsid %u not supported without CONFIG_BLK_DEV_ZONED\n",
                 info->nsid);
             return nvme_update_ns_info_generic(ns, info);
         }
         return nvme_update_ns_info_block(ns, info);
     case NVME_CSI_NVM:
         return nvme_update_ns_info_block(ns, info);
     default:
         dev_info(ns->ctrl->device,
             "block device for nsid %u not supported (csi %u)\n",
             info->nsid, info->ids.csi);
         return nvme_update_ns_info_generic(ns, info);
     }
 }
 
 static char nvme_pr_type(enum pr_type type)
 {
     switch (type) {
     case PR_WRITE_EXCLUSIVE:
         return 1;
     case PR_EXCLUSIVE_ACCESS:
         return 2;
     case PR_WRITE_EXCLUSIVE_REG_ONLY:
         return 3;
     case PR_EXCLUSIVE_ACCESS_REG_ONLY:
         return 4;
     case PR_WRITE_EXCLUSIVE_ALL_REGS:
         return 5;
     case PR_EXCLUSIVE_ACCESS_ALL_REGS:
         return 6;
     default:
         return 0;
     }
 }
 
 static int nvme_send_ns_head_pr_command(struct block_device *bdev,
         struct nvme_command *c, u8 data[16])
 {
     struct nvme_ns_head *head = bdev->bd_disk->private_data;
     int srcu_idx = srcu_read_lock(&head->srcu);
     struct nvme_ns *ns = nvme_find_path(head);
     int ret = -EWOULDBLOCK;
 
     if (ns) {
         c->common.nsid = cpu_to_le32(ns->head->ns_id);
         ret = nvme_submit_sync_cmd(ns->queue, c, data, 16);
     }
     srcu_read_unlock(&head->srcu, srcu_idx);
     return ret;
 }
     
 static int nvme_send_ns_pr_command(struct nvme_ns *ns, struct nvme_command *c,
         u8 data[16])
 {
     c->common.nsid = cpu_to_le32(ns->head->ns_id);
     return nvme_submit_sync_cmd(ns->queue, c, data, 16);
 }
 
 static int nvme_pr_command(struct block_device *bdev, u32 cdw10,
                 u64 key, u64 sa_key, u8 op)
 {
     struct nvme_command c = { };
     u8 data[16] = { 0, };
 
     put_unaligned_le64(key, &data[0]);
     put_unaligned_le64(sa_key, &data[8]);
 
     c.common.opcode = op;
     c.common.cdw10 = cpu_to_le32(cdw10);
 
     if (IS_ENABLED(CONFIG_NVME_MULTIPATH) &&
         bdev->bd_disk->fops == &nvme_ns_head_ops)
         return nvme_send_ns_head_pr_command(bdev, &c, data);
     return nvme_send_ns_pr_command(bdev->bd_disk->private_data, &c, data);
 }
 
 static int nvme_pr_register(struct block_device *bdev, u64 old,
         u64 new, unsigned flags)
 {
     u32 cdw10;
 
     if (flags & ~PR_FL_IGNORE_KEY)
         return -EOPNOTSUPP;
 
     cdw10 = old ? 2 : 0;
     cdw10 |= (flags & PR_FL_IGNORE_KEY) ? 1 << 3 : 0;
     cdw10 |= (1 << 30) | (1 << 31); /* PTPL=1 */
     return nvme_pr_command(bdev, cdw10, old, new, nvme_cmd_resv_register);
 }
 
 static int nvme_pr_reserve(struct block_device *bdev, u64 key,
         enum pr_type type, unsigned flags)
 {
     u32 cdw10;
 
     if (flags & ~PR_FL_IGNORE_KEY)
         return -EOPNOTSUPP;
 
     cdw10 = nvme_pr_type(type) << 8;
     cdw10 |= ((flags & PR_FL_IGNORE_KEY) ? 1 << 3 : 0);
     return nvme_pr_command(bdev, cdw10, key, 0, nvme_cmd_resv_acquire);
 }
 
 static int nvme_pr_preempt(struct block_device *bdev, u64 old, u64 new,
         enum pr_type type, bool abort)
 {
     u32 cdw10 = nvme_pr_type(type) << 8 | (abort ? 2 : 1);
 
     return nvme_pr_command(bdev, cdw10, old, new, nvme_cmd_resv_acquire);
 }
 
 static int nvme_pr_clear(struct block_device *bdev, u64 key)
 {
     u32 cdw10 = 1 | (key ? 0 : 1 << 3);
 
     return nvme_pr_command(bdev, cdw10, key, 0, nvme_cmd_resv_release);
 }
 
 static int nvme_pr_release(struct block_device *bdev, u64 key, enum pr_type type)
 {
     u32 cdw10 = nvme_pr_type(type) << 8 | (key ? 0 : 1 << 3);
 
     return nvme_pr_command(bdev, cdw10, key, 0, nvme_cmd_resv_release);
 }
 
 const struct pr_ops nvme_pr_ops = {
     .pr_register    = nvme_pr_register,
     .pr_reserve = nvme_pr_reserve,
     .pr_release = nvme_pr_release,
     .pr_preempt = nvme_pr_preempt,
     .pr_clear   = nvme_pr_clear,
 };
 
 #ifdef CONFIG_BLK_SED_OPAL
 int nvme_sec_submit(void *data, u16 spsp, u8 secp, void *buffer, size_t len,
         bool send)
 {
     struct nvme_ctrl *ctrl = data;
     struct nvme_command cmd = { };
 
     if (send)
         cmd.common.opcode = nvme_admin_security_send;
     else
         cmd.common.opcode = nvme_admin_security_recv;
     cmd.common.nsid = 0;
     cmd.common.cdw10 = cpu_to_le32(((u32)secp) << 24 | ((u32)spsp) << 8);
     cmd.common.cdw11 = cpu_to_le32(len);
 
     return __nvme_submit_sync_cmd(ctrl->admin_q, &cmd, NULL, buffer, len,
             NVME_QID_ANY, 1, 0);
 }
 EXPORT_SYMBOL_GPL(nvme_sec_submit);
 #endif /* CONFIG_BLK_SED_OPAL */
 
 #ifdef CONFIG_BLK_DEV_ZONED
 static int nvme_report_zones(struct gendisk *disk, sector_t sector,
         unsigned int nr_zones, report_zones_cb cb, void *data)
 {
     return nvme_ns_report_zones(disk->private_data, sector, nr_zones, cb,
             data);
 }
 #else
 #define nvme_report_zones   NULL
 #endif /* CONFIG_BLK_DEV_ZONED */
 
 static const struct block_device_operations nvme_bdev_ops = {
     .owner      = THIS_MODULE,
     .ioctl      = nvme_ioctl,
     .compat_ioctl   = blkdev_compat_ptr_ioctl,
     .open       = nvme_open,
     .release    = nvme_release,
     .getgeo     = nvme_getgeo,
     .report_zones   = nvme_report_zones,
     .pr_ops     = &nvme_pr_ops,
 };
 
 static int nvme_wait_ready(struct nvme_ctrl *ctrl, u32 timeout, bool enabled)
 {
     unsigned long timeout_jiffies = ((timeout + 1) * HZ / 2) + jiffies;
     u32 csts, bit = enabled ? NVME_CSTS_RDY : 0;
     int ret;
 
     while ((ret = ctrl->ops->reg_read32(ctrl, NVME_REG_CSTS, &csts)) == 0) {
         if (csts == ~0)
             return -ENODEV;
         if ((csts & NVME_CSTS_RDY) == bit)
             break;
 
         usleep_range(1000, 2000);
         if (fatal_signal_pending(current))
             return -EINTR;
         if (time_after(jiffies, timeout_jiffies)) {
             dev_err(ctrl->device,
                 "Device not ready; aborting %s, CSTS=0x%x\n",
                 enabled ? "initialisation" : "reset", csts);
             return -ENODEV;
         }
     }
 
     return ret;
 }
 
 /*
  * If the device has been passed off to us in an enabled state, just clear
  * the enabled bit.  The spec says we should set the 'shutdown notification
  * bits', but doing so may cause the device to complete commands to the
  * admin queue ... and we don't know what memory that might be pointing at!
  */
 int nvme_disable_ctrl(struct nvme_ctrl *ctrl)
 {
     int ret;
 
     ctrl->ctrl_config &= ~NVME_CC_SHN_MASK;
     ctrl->ctrl_config &= ~NVME_CC_ENABLE;
 
     ret = ctrl->ops->reg_write32(ctrl, NVME_REG_CC, ctrl->ctrl_config);
     if (ret)
         return ret;
 
     if (ctrl->quirks & NVME_QUIRK_DELAY_BEFORE_CHK_RDY)
         msleep(NVME_QUIRK_DELAY_AMOUNT);
 
     return nvme_wait_ready(ctrl, NVME_CAP_TIMEOUT(ctrl->cap), false);
 }
 EXPORT_SYMBOL_GPL(nvme_disable_ctrl);
 
 int nvme_enable_ctrl(struct nvme_ctrl *ctrl)
 {
     unsigned dev_page_min;
     u32 timeout;
     int ret;
 
     ret = ctrl->ops->reg_read64(ctrl, NVME_REG_CAP, &ctrl->cap);
     if (ret) {
         dev_err(ctrl->device, "Reading CAP failed (%d)\n", ret);
         return ret;
     }
     dev_page_min = NVME_CAP_MPSMIN(ctrl->cap) + 12;
 
     if (NVME_CTRL_PAGE_SHIFT < dev_page_min) {
         dev_err(ctrl->device,
             "Minimum device page size %u too large for host (%u)\n",
             1 << dev_page_min, 1 << NVME_CTRL_PAGE_SHIFT);
         return -ENODEV;
     }
 
     if (NVME_CAP_CSS(ctrl->cap) & NVME_CAP_CSS_CSI)
         ctrl->ctrl_config = NVME_CC_CSS_CSI;
     else
         ctrl->ctrl_config = NVME_CC_CSS_NVM;
 
     if (ctrl->cap & NVME_CAP_CRMS_CRWMS) {
         u32 crto;
 
         ret = ctrl->ops->reg_read32(ctrl, NVME_REG_CRTO, &crto);
         if (ret) {
             dev_err(ctrl->device, "Reading CRTO failed (%d)\n",
                 ret);
             return ret;
         }
 
         if (ctrl->cap & NVME_CAP_CRMS_CRIMS) {
             ctrl->ctrl_config |= NVME_CC_CRIME;
             timeout = NVME_CRTO_CRIMT(crto);
         } else {
             timeout = NVME_CRTO_CRWMT(crto);
         }
     } else {
         timeout = NVME_CAP_TIMEOUT(ctrl->cap);
     }
 
     ctrl->ctrl_config |= (NVME_CTRL_PAGE_SHIFT - 12) << NVME_CC_MPS_SHIFT;
     ctrl->ctrl_config |= NVME_CC_AMS_RR | NVME_CC_SHN_NONE;
     ctrl->ctrl_config |= NVME_CC_IOSQES | NVME_CC_IOCQES;
     ret = ctrl->ops->reg_write32(ctrl, NVME_REG_CC, ctrl->ctrl_config);
     if (ret)
         return ret;
 
     /* Flush write to device (required if transport is PCI) */
     ret = ctrl->ops->reg_read32(ctrl, NVME_REG_CC, &ctrl->ctrl_config);
     if (ret)
         return ret;
 
     ctrl->ctrl_config |= NVME_CC_ENABLE;
     ret = ctrl->ops->reg_write32(ctrl, NVME_REG_CC, ctrl->ctrl_config);
     if (ret)
         return ret;
     return nvme_wait_ready(ctrl, timeout, true);
 }
 EXPORT_SYMBOL_GPL(nvme_enable_ctrl);
 
 int nvme_shutdown_ctrl(struct nvme_ctrl *ctrl)
 {
     unsigned long timeout = jiffies + (ctrl->shutdown_timeout * HZ);
     u32 csts;
     int ret;
 
     ctrl->ctrl_config &= ~NVME_CC_SHN_MASK;
     ctrl->ctrl_config |= NVME_CC_SHN_NORMAL;
 
     ret = ctrl->ops->reg_write32(ctrl, NVME_REG_CC, ctrl->ctrl_config);
     if (ret)
         return ret;
 
     while ((ret = ctrl->ops->reg_read32(ctrl, NVME_REG_CSTS, &csts)) == 0) {
         if ((csts & NVME_CSTS_SHST_MASK) == NVME_CSTS_SHST_CMPLT)
             break;
 
         msleep(100);
         if (fatal_signal_pending(current))
             return -EINTR;
         if (time_after(jiffies, timeout)) {
             dev_err(ctrl->device,
                 "Device shutdown incomplete; abort shutdown\n");
             return -ENODEV;
         }
     }
 
     return ret;
 }
 EXPORT_SYMBOL_GPL(nvme_shutdown_ctrl);
 
 static int nvme_configure_timestamp(struct nvme_ctrl *ctrl)
 {
     __le64 ts;
     int ret;
 
     if (!(ctrl->oncs & NVME_CTRL_ONCS_TIMESTAMP))
         return 0;
 
     ts = cpu_to_le64(ktime_to_ms(ktime_get_real()));
     ret = nvme_set_features(ctrl, NVME_FEAT_TIMESTAMP, 0, &ts, sizeof(ts),
             NULL);
     if (ret)
         dev_warn_once(ctrl->device,
             "could not set timestamp (%d)\n", ret);
     return ret;
 }
 
 static int nvme_configure_host_options(struct nvme_ctrl *ctrl)
 {
     struct nvme_feat_host_behavior *host;
     u8 acre = 0, lbafee = 0;
     int ret;
 
     /* Don't bother enabling the feature if retry delay is not reported */
     if (ctrl->crdt[0])
         acre = NVME_ENABLE_ACRE;
     if (ctrl->ctratt & NVME_CTRL_ATTR_ELBAS)
         lbafee = NVME_ENABLE_LBAFEE;
 
     if (!acre && !lbafee)
         return 0;
 
     host = kzalloc(sizeof(*host), GFP_KERNEL);
     if (!host)
         return 0;
 
     host->acre = acre;
     host->lbafee = lbafee;
     ret = nvme_set_features(ctrl, NVME_FEAT_HOST_BEHAVIOR, 0,
                 host, sizeof(*host), NULL);
     kfree(host);
     return ret;
 }
 
 /*
  * The function checks whether the given total (exlat + enlat) latency of
  * a power state allows the latter to be used as an APST transition target.
  * It does so by comparing the latency to the primary and secondary latency
  * tolerances defined by module params. If there's a match, the corresponding
  * timeout value is returned and the matching tolerance index (1 or 2) is
  * reported.
  */
 static bool nvme_apst_get_transition_time(u64 total_latency,
         u64 *transition_time, unsigned *last_index)
 {
     if (total_latency <= apst_primary_latency_tol_us) {
         if (*last_index == 1)
             return false;
         *last_index = 1;
         *transition_time = apst_primary_timeout_ms;
         return true;
     }
     if (apst_secondary_timeout_ms &&
         total_latency <= apst_secondary_latency_tol_us) {
         if (*last_index <= 2)
             return false;
         *last_index = 2;
         *transition_time = apst_secondary_timeout_ms;
         return true;
     }
     return false;
 }
 
 /*
  * APST (Autonomous Power State Transition) lets us program a table of power
  * state transitions that the controller will perform automatically.
  *
  * Depending on module params, one of the two supported techniques will be used:
  *
  * - If the parameters provide explicit timeouts and tolerances, they will be
  *   used to build a table with up to 2 non-operational states to transition to.
  *   The default parameter values were selected based on the values used by
  *   Microsoft's and Intel's NVMe drivers. Yet, since we don't implement dynamic
  *   regeneration of the APST table in the event of switching between external
  *   and battery power, the timeouts and tolerances reflect a compromise
  *   between values used by Microsoft for AC and battery scenarios.
  * - If not, we'll configure the table with a simple heuristic: we are willing
  *   to spend at most 2% of the time transitioning between power states.
  *   Therefore, when running in any given state, we will enter the next
  *   lower-power non-operational state after waiting 50 * (enlat + exlat)
  *   microseconds, as long as that state's exit latency is under the requested
  *   maximum latency.
  *
  * We will not autonomously enter any non-operational state for which the total
  * latency exceeds ps_max_latency_us.
  *
  * Users can set ps_max_latency_us to zero to turn off APST.
  */
 static int nvme_configure_apst(struct nvme_ctrl *ctrl)
 {
     struct nvme_feat_auto_pst *table;
     unsigned apste = 0;
     u64 max_lat_us = 0;
     __le64 target = 0;
     int max_ps = -1;
     int state;
     int ret;
     unsigned last_lt_index = UINT_MAX;
 
     /*
      * If APST isn't supported or if we haven't been initialized yet,
      * then don't do anything.
      */
     if (!ctrl->apsta)
         return 0;
 
     if (ctrl->npss > 31) {
         dev_warn(ctrl->device, "NPSS is invalid; not using APST\n");
         return 0;
     }
 
     table = kzalloc(sizeof(*table), GFP_KERNEL);
     if (!table)
         return 0;
 
     if (!ctrl->apst_enabled || ctrl->ps_max_latency_us == 0) {
         /* Turn off APST. */
         dev_dbg(ctrl->device, "APST disabled\n");
         goto done;
     }
 
     /*
      * Walk through all states from lowest- to highest-power.
      * According to the spec, lower-numbered states use more power.  NPSS,
      * despite the name, is the index of the lowest-power state, not the
      * number of states.
      */
     for (state = (int)ctrl->npss; state >= 0; state--) {
         u64 total_latency_us, exit_latency_us, transition_ms;
 
         if (target)
             table->entries[state] = target;
 
         /*
          * Don't allow transitions to the deepest state if it's quirked
          * off.
          */
         if (state == ctrl->npss &&
             (ctrl->quirks & NVME_QUIRK_NO_DEEPEST_PS))
             continue;
 
         /*
          * Is this state a useful non-operational state for higher-power
          * states to autonomously transition to?
          */
         if (!(ctrl->psd[state].flags & NVME_PS_FLAGS_NON_OP_STATE))
             continue;
 
         exit_latency_us = (u64)le32_to_cpu(ctrl->psd[state].exit_lat);
         if (exit_latency_us > ctrl->ps_max_latency_us)
             continue;
 
         total_latency_us = exit_latency_us +
             le32_to_cpu(ctrl->psd[state].entry_lat);
 
         /*
          * This state is good. It can be used as the APST idle target
          * for higher power states.
          */
         if (apst_primary_timeout_ms && apst_primary_latency_tol_us) {
             if (!nvme_apst_get_transition_time(total_latency_us,
                     &transition_ms, &last_lt_index))
                 continue;
         } else {
             transition_ms = total_latency_us + 19;
             do_div(transition_ms, 20);
             if (transition_ms > (1 << 24) - 1)
                 transition_ms = (1 << 24) - 1;
         }
 
         target = cpu_to_le64((state << 3) | (transition_ms << 8));
         if (max_ps == -1)
             max_ps = state;
         if (total_latency_us > max_lat_us)
             max_lat_us = total_latency_us;
     }
 
     if (max_ps == -1)
         dev_dbg(ctrl->device, "APST enabled but no non-operational states are available\n");
     else
         dev_dbg(ctrl->device, "APST enabled: max PS = %d, max round-trip latency = %lluus, table = %*phN\n",
             max_ps, max_lat_us, (int)sizeof(*table), table);
     apste = 1;
 
 done:
     ret = nvme_set_features(ctrl, NVME_FEAT_AUTO_PST, apste,
                 table, sizeof(*table), NULL);
     if (ret)
         dev_err(ctrl->device, "failed to set APST feature (%d)\n", ret);
     kfree(table);
     return ret;
 }
 
 static void nvme_set_latency_tolerance(struct device *dev, s32 val)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
     u64 latency;
 
     switch (val) {
     case PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT:
     case PM_QOS_LATENCY_ANY:
         latency = U64_MAX;
         break;
 
     default:
         latency = val;
     }
 
     if (ctrl->ps_max_latency_us != latency) {
         ctrl->ps_max_latency_us = latency;
         if (ctrl->state == NVME_CTRL_LIVE)
             nvme_configure_apst(ctrl);
     }
 }
 
 struct nvme_core_quirk_entry {
     /*
      * NVMe model and firmware strings are padded with spaces.  For
      * simplicity, strings in the quirk table are padded with NULLs
      * instead.
      */
     u16 vid;
     const char *mn;
     const char *fr;
     unsigned long quirks;
 };
 
 static const struct nvme_core_quirk_entry core_quirks[] = {
     {
         /*
          * This Toshiba device seems to die using any APST states.  See:
          * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1678184/comments/11
          */
         .vid = 0x1179,
         .mn = "THNSF5256GPUK TOSHIBA",
         .quirks = NVME_QUIRK_NO_APST,
     },
     {
         /*
          * This LiteON CL1-3D*-Q11 firmware version has a race
          * condition associated with actions related to suspend to idle
          * LiteON has resolved the problem in future firmware
          */
         .vid = 0x14a4,
         .fr = "22301111",
         .quirks = NVME_QUIRK_SIMPLE_SUSPEND,
     },
     {
         /*
          * This Kioxia CD6-V Series / HPE PE8030 device times out and
          * aborts I/O during any load, but more easily reproducible
          * with discards (fstrim).
          *
          * The device is left in a state where it is also not possible
          * to use "nvme set-feature" to disable APST, but booting with
          * nvme_core.default_ps_max_latency=0 works.
          */
         .vid = 0x1e0f,
         .mn = "KCD6XVUL6T40",
         .quirks = NVME_QUIRK_NO_APST,
     },
     {
         /*
          * The external Samsung X5 SSD fails initialization without a
          * delay before checking if it is ready and has a whole set of
          * other problems.  To make this even more interesting, it
          * shares the PCI ID with internal Samsung 970 Evo Plus that
          * does not need or want these quirks.
          */
         .vid = 0x144d,
         .mn = "Samsung Portable SSD X5",
         .quirks = NVME_QUIRK_DELAY_BEFORE_CHK_RDY |
               NVME_QUIRK_NO_DEEPEST_PS |
               NVME_QUIRK_IGNORE_DEV_SUBNQN,
     }
 };
 
 /* match is null-terminated but idstr is space-padded. */
 static bool string_matches(const char *idstr, const char *match, size_t len)
 {
     size_t matchlen;
 
     if (!match)
         return true;
 
     matchlen = strlen(match);
     WARN_ON_ONCE(matchlen > len);
 
     if (memcmp(idstr, match, matchlen))
         return false;
 
     for (; matchlen < len; matchlen++)
         if (idstr[matchlen] != ' ')
             return false;
 
     return true;
 }
 
 static bool quirk_matches(const struct nvme_id_ctrl *id,
               const struct nvme_core_quirk_entry *q)
 {
     return q->vid == le16_to_cpu(id->vid) &&
         string_matches(id->mn, q->mn, sizeof(id->mn)) &&
         string_matches(id->fr, q->fr, sizeof(id->fr));
 }
 
 static void nvme_init_subnqn(struct nvme_subsystem *subsys, struct nvme_ctrl *ctrl,
         struct nvme_id_ctrl *id)
 {
     size_t nqnlen;
     int off;
 
     if(!(ctrl->quirks & NVME_QUIRK_IGNORE_DEV_SUBNQN)) {
         nqnlen = strnlen(id->subnqn, NVMF_NQN_SIZE);
         if (nqnlen > 0 && nqnlen < NVMF_NQN_SIZE) {
             strlcpy(subsys->subnqn, id->subnqn, NVMF_NQN_SIZE);
             return;
         }
 
         if (ctrl->vs >= NVME_VS(1, 2, 1))
             dev_warn(ctrl->device, "missing or invalid SUBNQN field.\n");
     }
 
     /* Generate a "fake" NQN per Figure 254 in NVMe 1.3 + ECN 001 */
     off = snprintf(subsys->subnqn, NVMF_NQN_SIZE,
             "nqn.2014.08.org.nvmexpress:%04x%04x",
             le16_to_cpu(id->vid), le16_to_cpu(id->ssvid));
     memcpy(subsys->subnqn + off, id->sn, sizeof(id->sn));
     off += sizeof(id->sn);
     memcpy(subsys->subnqn + off, id->mn, sizeof(id->mn));
     off += sizeof(id->mn);
     memset(subsys->subnqn + off, 0, sizeof(subsys->subnqn) - off);
 }
 
 static void nvme_release_subsystem(struct device *dev)
 {
     struct nvme_subsystem *subsys =
         container_of(dev, struct nvme_subsystem, dev);
 
     if (subsys->instance >= 0)
         ida_free(&nvme_instance_ida, subsys->instance);
     kfree(subsys);
 }
 
 static void nvme_destroy_subsystem(struct kref *ref)
 {
     struct nvme_subsystem *subsys =
             container_of(ref, struct nvme_subsystem, ref);
 
     mutex_lock(&nvme_subsystems_lock);
     list_del(&subsys->entry);
     mutex_unlock(&nvme_subsystems_lock);
 
     ida_destroy(&subsys->ns_ida);
     device_del(&subsys->dev);
     put_device(&subsys->dev);
 }
 
 static void nvme_put_subsystem(struct nvme_subsystem *subsys)
 {
     kref_put(&subsys->ref, nvme_destroy_subsystem);
 }
 
 static struct nvme_subsystem *__nvme_find_get_subsystem(const char *subsysnqn)
 {
     struct nvme_subsystem *subsys;
 
     lockdep_assert_held(&nvme_subsystems_lock);
 
     /*
      * Fail matches for discovery subsystems. This results
      * in each discovery controller bound to a unique subsystem.
      * This avoids issues with validating controller values
      * that can only be true when there is a single unique subsystem.
      * There may be multiple and completely independent entities
      * that provide discovery controllers.
      */
     if (!strcmp(subsysnqn, NVME_DISC_SUBSYS_NAME))
         return NULL;
 
     list_for_each_entry(subsys, &nvme_subsystems, entry) {
         if (strcmp(subsys->subnqn, subsysnqn))
             continue;
         if (!kref_get_unless_zero(&subsys->ref))
             continue;
         return subsys;
     }
 
     return NULL;
 }
 
 #define SUBSYS_ATTR_RO(_name, _mode, _show)         \
     struct device_attribute subsys_attr_##_name = \
         __ATTR(_name, _mode, _show, NULL)
 
 static ssize_t nvme_subsys_show_nqn(struct device *dev,
                     struct device_attribute *attr,
                     char *buf)
 {
     struct nvme_subsystem *subsys =
         container_of(dev, struct nvme_subsystem, dev);
 
     return sysfs_emit(buf, "%s\n", subsys->subnqn);
 }
 static SUBSYS_ATTR_RO(subsysnqn, S_IRUGO, nvme_subsys_show_nqn);
 
 static ssize_t nvme_subsys_show_type(struct device *dev,
                     struct device_attribute *attr,
                     char *buf)
 {
     struct nvme_subsystem *subsys =
         container_of(dev, struct nvme_subsystem, dev);
 
     switch (subsys->subtype) {
     case NVME_NQN_DISC:
         return sysfs_emit(buf, "discovery\n");
     case NVME_NQN_NVME:
         return sysfs_emit(buf, "nvm\n");
     default:
         return sysfs_emit(buf, "reserved\n");
     }
 }
 static SUBSYS_ATTR_RO(subsystype, S_IRUGO, nvme_subsys_show_type);
 
 #define nvme_subsys_show_str_function(field)                \
 static ssize_t subsys_##field##_show(struct device *dev,        \
                 struct device_attribute *attr, char *buf)   \
 {                                   \
     struct nvme_subsystem *subsys =                 \
         container_of(dev, struct nvme_subsystem, dev);      \
     return sysfs_emit(buf, "%.*s\n",                \
                (int)sizeof(subsys->field), subsys->field);  \
 }                                   \
 static SUBSYS_ATTR_RO(field, S_IRUGO, subsys_##field##_show);
 
 nvme_subsys_show_str_function(model);
 nvme_subsys_show_str_function(serial);
 nvme_subsys_show_str_function(firmware_rev);
 
 static struct attribute *nvme_subsys_attrs[] = {
     &subsys_attr_model.attr,
     &subsys_attr_serial.attr,
     &subsys_attr_firmware_rev.attr,
     &subsys_attr_subsysnqn.attr,
     &subsys_attr_subsystype.attr,
 #ifdef CONFIG_NVME_MULTIPATH
     &subsys_attr_iopolicy.attr,
 #endif
     NULL,
 };
 
 static const struct attribute_group nvme_subsys_attrs_group = {
     .attrs = nvme_subsys_attrs,
 };
 
 static const struct attribute_group *nvme_subsys_attrs_groups[] = {
     &nvme_subsys_attrs_group,
     NULL,
 };
 
 static inline bool nvme_discovery_ctrl(struct nvme_ctrl *ctrl)
 {
     return ctrl->opts && ctrl->opts->discovery_nqn;
 }
 
 static bool nvme_validate_cntlid(struct nvme_subsystem *subsys,
         struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 {
     struct nvme_ctrl *tmp;
 
     lockdep_assert_held(&nvme_subsystems_lock);
 
     list_for_each_entry(tmp, &subsys->ctrls, subsys_entry) {
         if (nvme_state_terminal(tmp))
             continue;
 
         if (tmp->cntlid == ctrl->cntlid) {
             dev_err(ctrl->device,
                 "Duplicate cntlid %u with %s, subsys %s, rejecting\n",
                 ctrl->cntlid, dev_name(tmp->device),
                 subsys->subnqn);
             return false;
         }
 
         if ((id->cmic & NVME_CTRL_CMIC_MULTI_CTRL) ||
             nvme_discovery_ctrl(ctrl))
             continue;
 
         dev_err(ctrl->device,
             "Subsystem does not support multiple controllers\n");
         return false;
     }
 
     return true;
 }
 
 static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 {
     struct nvme_subsystem *subsys, *found;
     int ret;
 
     subsys = kzalloc(sizeof(*subsys), GFP_KERNEL);
     if (!subsys)
         return -ENOMEM;
 
     subsys->instance = -1;
     mutex_init(&subsys->lock);
     kref_init(&subsys->ref);
     INIT_LIST_HEAD(&subsys->ctrls);
     INIT_LIST_HEAD(&subsys->nsheads);
     nvme_init_subnqn(subsys, ctrl, id);
     memcpy(subsys->serial, id->sn, sizeof(subsys->serial));
     memcpy(subsys->model, id->mn, sizeof(subsys->model));
     memcpy(subsys->firmware_rev, id->fr, sizeof(subsys->firmware_rev));
     subsys->vendor_id = le16_to_cpu(id->vid);
     subsys->cmic = id->cmic;
 
     /* Versions prior to 1.4 don't necessarily report a valid type */
     if (id->cntrltype == NVME_CTRL_DISC ||
         !strcmp(subsys->subnqn, NVME_DISC_SUBSYS_NAME))
         subsys->subtype = NVME_NQN_DISC;
     else
         subsys->subtype = NVME_NQN_NVME;
 
     if (nvme_discovery_ctrl(ctrl) && subsys->subtype != NVME_NQN_DISC) {
         dev_err(ctrl->device,
             "Subsystem %s is not a discovery controller",
             subsys->subnqn);
         kfree(subsys);
         return -EINVAL;
     }
     subsys->awupf = le16_to_cpu(id->awupf);
     nvme_mpath_default_iopolicy(subsys);
 
     subsys->dev.class = nvme_subsys_class;
     subsys->dev.release = nvme_release_subsystem;
     subsys->dev.groups = nvme_subsys_attrs_groups;
     dev_set_name(&subsys->dev, "nvme-subsys%d", ctrl->instance);
     device_initialize(&subsys->dev);
 
     mutex_lock(&nvme_subsystems_lock);
     found = __nvme_find_get_subsystem(subsys->subnqn);
     if (found) {
         put_device(&subsys->dev);
         subsys = found;
 
         if (!nvme_validate_cntlid(subsys, ctrl, id)) {
             ret = -EINVAL;
             goto out_put_subsystem;
         }
     } else {
         ret = device_add(&subsys->dev);
         if (ret) {
             dev_err(ctrl->device,
                 "failed to register subsystem device.\n");
             put_device(&subsys->dev);
             goto out_unlock;
         }
         ida_init(&subsys->ns_ida);
         list_add_tail(&subsys->entry, &nvme_subsystems);
     }
 
     ret = sysfs_create_link(&subsys->dev.kobj, &ctrl->device->kobj,
                 dev_name(ctrl->device));
     if (ret) {
         dev_err(ctrl->device,
             "failed to create sysfs link from subsystem.\n");
         goto out_put_subsystem;
     }
 
     if (!found)
         subsys->instance = ctrl->instance;
     ctrl->subsys = subsys;
     list_add_tail(&ctrl->subsys_entry, &subsys->ctrls);
     mutex_unlock(&nvme_subsystems_lock);
     return 0;
 
 out_put_subsystem:
     nvme_put_subsystem(subsys);
 out_unlock:
     mutex_unlock(&nvme_subsystems_lock);
     return ret;
 }
 
 int nvme_get_log(struct nvme_ctrl *ctrl, u32 nsid, u8 log_page, u8 lsp, u8 csi,
         void *log, size_t size, u64 offset)
 {
     struct nvme_command c = { };
     u32 dwlen = nvme_bytes_to_numd(size);
 
     c.get_log_page.opcode = nvme_admin_get_log_page;
     c.get_log_page.nsid = cpu_to_le32(nsid);
     c.get_log_page.lid = log_page;
     c.get_log_page.lsp = lsp;
     c.get_log_page.numdl = cpu_to_le16(dwlen & ((1 << 16) - 1));
     c.get_log_page.numdu = cpu_to_le16(dwlen >> 16);
     c.get_log_page.lpol = cpu_to_le32(lower_32_bits(offset));
     c.get_log_page.lpou = cpu_to_le32(upper_32_bits(offset));
     c.get_log_page.csi = csi;
 
     return nvme_submit_sync_cmd(ctrl->admin_q, &c, log, size);
 }
 
 static int nvme_get_effects_log(struct nvme_ctrl *ctrl, u8 csi,
                 struct nvme_effects_log **log)
 {
     struct nvme_effects_log *cel = xa_load(&ctrl->cels, csi);
     int ret;
 
     if (cel)
         goto out;
 
     cel = kzalloc(sizeof(*cel), GFP_KERNEL);
     if (!cel)
         return -ENOMEM;
 
     ret = nvme_get_log(ctrl, 0x00, NVME_LOG_CMD_EFFECTS, 0, csi,
             cel, sizeof(*cel), 0);
     if (ret) {
         kfree(cel);
         return ret;
     }
 
     xa_store(&ctrl->cels, csi, cel, GFP_KERNEL);
 out:
     *log = cel;
     return 0;
 }
 
 static inline u32 nvme_mps_to_sectors(struct nvme_ctrl *ctrl, u32 units)
 {
     u32 page_shift = NVME_CAP_MPSMIN(ctrl->cap) + 12, val;
 
     if (check_shl_overflow(1U, units + page_shift - 9, &val))
         return UINT_MAX;
     return val;
 }
 
 static int nvme_init_non_mdts_limits(struct nvme_ctrl *ctrl)
 {
     struct nvme_command c = { };
     struct nvme_id_ctrl_nvm *id;
     int ret;
 
     if (ctrl->oncs & NVME_CTRL_ONCS_DSM) {
         ctrl->max_discard_sectors = UINT_MAX;
         ctrl->max_discard_segments = NVME_DSM_MAX_RANGES;
     } else {
         ctrl->max_discard_sectors = 0;
         ctrl->max_discard_segments = 0;
     }
 
     /*
      * Even though NVMe spec explicitly states that MDTS is not applicable
      * to the write-zeroes, we are cautious and limit the size to the
      * controllers max_hw_sectors value, which is based on the MDTS field
      * and possibly other limiting factors.
      */
     if ((ctrl->oncs & NVME_CTRL_ONCS_WRITE_ZEROES) &&
         !(ctrl->quirks & NVME_QUIRK_DISABLE_WRITE_ZEROES))
         ctrl->max_zeroes_sectors = ctrl->max_hw_sectors;
     else
         ctrl->max_zeroes_sectors = 0;
 
     if (nvme_ctrl_limited_cns(ctrl))
         return 0;
 
     id = kzalloc(sizeof(*id), GFP_KERNEL);
     if (!id)
         return 0;
 
     c.identify.opcode = nvme_admin_identify;
     c.identify.cns = NVME_ID_CNS_CS_CTRL;
     c.identify.csi = NVME_CSI_NVM;
 
     ret = nvme_submit_sync_cmd(ctrl->admin_q, &c, id, sizeof(*id));
     if (ret)
         goto free_data;
 
     if (id->dmrl)
         ctrl->max_discard_segments = id->dmrl;
     ctrl->dmrsl = le32_to_cpu(id->dmrsl);
     if (id->wzsl)
         ctrl->max_zeroes_sectors = nvme_mps_to_sectors(ctrl, id->wzsl);
 
 free_data:
     kfree(id);
     return ret;
 }
 
 static int nvme_init_identify(struct nvme_ctrl *ctrl)
 {
     struct nvme_id_ctrl *id;
     u32 max_hw_sectors;
     bool prev_apst_enabled;
     int ret;
 
     ret = nvme_identify_ctrl(ctrl, &id);
     if (ret) {
         dev_err(ctrl->device, "Identify Controller failed (%d)\n", ret);
         return -EIO;
     }
 
     if (id->lpa & NVME_CTRL_LPA_CMD_EFFECTS_LOG) {
         ret = nvme_get_effects_log(ctrl, NVME_CSI_NVM, &ctrl->effects);
         if (ret < 0)
             goto out_free;
     }
 
     if (!(ctrl->ops->flags & NVME_F_FABRICS))
         ctrl->cntlid = le16_to_cpu(id->cntlid);
 
     if (!ctrl->identified) {
         unsigned int i;
 
         ret = nvme_init_subsystem(ctrl, id);
         if (ret)
             goto out_free;
 
         /*
          * Check for quirks.  Quirk can depend on firmware version,
          * so, in principle, the set of quirks present can change
          * across a reset.  As a possible future enhancement, we
          * could re-scan for quirks every time we reinitialize
          * the device, but we'd have to make sure that the driver
          * behaves intelligently if the quirks change.
          */
         for (i = 0; i < ARRAY_SIZE(core_quirks); i++) {
             if (quirk_matches(id, &core_quirks[i]))
                 ctrl->quirks |= core_quirks[i].quirks;
         }
     }
 
     if (force_apst && (ctrl->quirks & NVME_QUIRK_NO_DEEPEST_PS)) {
         dev_warn(ctrl->device, "forcibly allowing all power states due to nvme_core.force_apst -- use at your own risk\n");
         ctrl->quirks &= ~NVME_QUIRK_NO_DEEPEST_PS;
     }
 
     ctrl->crdt[0] = le16_to_cpu(id->crdt1);
     ctrl->crdt[1] = le16_to_cpu(id->crdt2);
     ctrl->crdt[2] = le16_to_cpu(id->crdt3);
 
     ctrl->oacs = le16_to_cpu(id->oacs);
     ctrl->oncs = le16_to_cpu(id->oncs);
     ctrl->mtfa = le16_to_cpu(id->mtfa);
     ctrl->oaes = le32_to_cpu(id->oaes);
     ctrl->wctemp = le16_to_cpu(id->wctemp);
     ctrl->cctemp = le16_to_cpu(id->cctemp);
 
     atomic_set(&ctrl->abort_limit, id->acl + 1);
     ctrl->vwc = id->vwc;
     if (id->mdts)
         max_hw_sectors = nvme_mps_to_sectors(ctrl, id->mdts);
     else
         max_hw_sectors = UINT_MAX;
     ctrl->max_hw_sectors =
         min_not_zero(ctrl->max_hw_sectors, max_hw_sectors);
 
     nvme_set_queue_limits(ctrl, ctrl->admin_q);
     ctrl->sgls = le32_to_cpu(id->sgls);
     ctrl->kas = le16_to_cpu(id->kas);
     ctrl->max_namespaces = le32_to_cpu(id->mnan);
     ctrl->ctratt = le32_to_cpu(id->ctratt);
 
     ctrl->cntrltype = id->cntrltype;
     ctrl->dctype = id->dctype;
 
     if (id->rtd3e) {
         /* us -> s */
         u32 transition_time = le32_to_cpu(id->rtd3e) / USEC_PER_SEC;
 
         ctrl->shutdown_timeout = clamp_t(unsigned int, transition_time,
                          shutdown_timeout, 60);
 
         if (ctrl->shutdown_timeout != shutdown_timeout)
             dev_info(ctrl->device,
                  "Shutdown timeout set to %u seconds\n",
                  ctrl->shutdown_timeout);
     } else
         ctrl->shutdown_timeout = shutdown_timeout;
 
     ctrl->npss = id->npss;
     ctrl->apsta = id->apsta;
     prev_apst_enabled = ctrl->apst_enabled;
     if (ctrl->quirks & NVME_QUIRK_NO_APST) {
         if (force_apst && id->apsta) {
             dev_warn(ctrl->device, "forcibly allowing APST due to nvme_core.force_apst -- use at your own risk\n");
             ctrl->apst_enabled = true;
         } else {
             ctrl->apst_enabled = false;
         }
     } else {
         ctrl->apst_enabled = id->apsta;
     }
     memcpy(ctrl->psd, id->psd, sizeof(ctrl->psd));
 
     if (ctrl->ops->flags & NVME_F_FABRICS) {
         ctrl->icdoff = le16_to_cpu(id->icdoff);
         ctrl->ioccsz = le32_to_cpu(id->ioccsz);
         ctrl->iorcsz = le32_to_cpu(id->iorcsz);
         ctrl->maxcmd = le16_to_cpu(id->maxcmd);
 
         /*
          * In fabrics we need to verify the cntlid matches the
          * admin connect
          */
         if (ctrl->cntlid != le16_to_cpu(id->cntlid)) {
             dev_err(ctrl->device,
                 "Mismatching cntlid: Connect %u vs Identify "
                 "%u, rejecting\n",
                 ctrl->cntlid, le16_to_cpu(id->cntlid));
             ret = -EINVAL;
             goto out_free;
         }
 
         if (!nvme_discovery_ctrl(ctrl) && !ctrl->kas) {
             dev_err(ctrl->device,
                 "keep-alive support is mandatory for fabrics\n");
             ret = -EINVAL;
             goto out_free;
         }
     } else {
         ctrl->hmpre = le32_to_cpu(id->hmpre);
         ctrl->hmmin = le32_to_cpu(id->hmmin);
         ctrl->hmminds = le32_to_cpu(id->hmminds);
         ctrl->hmmaxd = le16_to_cpu(id->hmmaxd);
     }
 
     ret = nvme_mpath_init_identify(ctrl, id);
     if (ret < 0)
         goto out_free;
 
     if (ctrl->apst_enabled && !prev_apst_enabled)
         dev_pm_qos_expose_latency_tolerance(ctrl->device);
     else if (!ctrl->apst_enabled && prev_apst_enabled)
         dev_pm_qos_hide_latency_tolerance(ctrl->device);
 
 out_free:
     kfree(id);
     return ret;
 }
 
 /*
  * Initialize the cached copies of the Identify data and various controller
  * register in our nvme_ctrl structure.  This should be called as soon as
  * the admin queue is fully up and running.
  */
 int nvme_init_ctrl_finish(struct nvme_ctrl *ctrl)
 {
     int ret;
 
     ret = ctrl->ops->reg_read32(ctrl, NVME_REG_VS, &ctrl->vs);
     if (ret) {
         dev_err(ctrl->device, "Reading VS failed (%d)\n", ret);
         return ret;
     }
 
     ctrl->sqsize = min_t(u16, NVME_CAP_MQES(ctrl->cap), ctrl->sqsize);
 
     if (ctrl->vs >= NVME_VS(1, 1, 0))
         ctrl->subsystem = NVME_CAP_NSSRC(ctrl->cap);
 
     ret = nvme_init_identify(ctrl);
     if (ret)
         return ret;
 
     ret = nvme_configure_apst(ctrl);
     if (ret < 0)
         return ret;
 
     ret = nvme_configure_timestamp(ctrl);
     if (ret < 0)
         return ret;
 
     ret = nvme_configure_host_options(ctrl);
     if (ret < 0)
         return ret;
 
     if (!ctrl->identified && !nvme_discovery_ctrl(ctrl)) {
         ret = nvme_hwmon_init(ctrl);
         if (ret < 0)
             return ret;
     }
 
     ctrl->identified = true;
 
     return 0;
 }
 EXPORT_SYMBOL_GPL(nvme_init_ctrl_finish);
 
 static int nvme_dev_open(struct inode *inode, struct file *file)
 {
     struct nvme_ctrl *ctrl =
         container_of(inode->i_cdev, struct nvme_ctrl, cdev);
 
     switch (ctrl->state) {
     case NVME_CTRL_LIVE:
         break;
     default:
         return -EWOULDBLOCK;
     }
 
     nvme_get_ctrl(ctrl);
     if (!try_module_get(ctrl->ops->module)) {
         nvme_put_ctrl(ctrl);
         return -EINVAL;
     }
 
     file->private_data = ctrl;
     return 0;
 }
 
 static int nvme_dev_release(struct inode *inode, struct file *file)
 {
     struct nvme_ctrl *ctrl =
         container_of(inode->i_cdev, struct nvme_ctrl, cdev);
 
     module_put(ctrl->ops->module);
     nvme_put_ctrl(ctrl);
     return 0;
 }
 
 static const struct file_operations nvme_dev_fops = {
     .owner      = THIS_MODULE,
     .open       = nvme_dev_open,
     .release    = nvme_dev_release,
     .unlocked_ioctl = nvme_dev_ioctl,
     .compat_ioctl   = compat_ptr_ioctl,
     .uring_cmd  = nvme_dev_uring_cmd,
 };
 
 static ssize_t nvme_sysfs_reset(struct device *dev,
                 struct device_attribute *attr, const char *buf,
                 size_t count)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
     int ret;
 
     ret = nvme_reset_ctrl_sync(ctrl);
     if (ret < 0)
         return ret;
     return count;
 }
 static DEVICE_ATTR(reset_controller, S_IWUSR, NULL, nvme_sysfs_reset);
 
 static ssize_t nvme_sysfs_rescan(struct device *dev,
                 struct device_attribute *attr, const char *buf,
                 size_t count)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
 
     nvme_queue_scan(ctrl);
     return count;
 }
 static DEVICE_ATTR(rescan_controller, S_IWUSR, NULL, nvme_sysfs_rescan);
 
 static inline struct nvme_ns_head *dev_to_ns_head(struct device *dev)
 {
     struct gendisk *disk = dev_to_disk(dev);
 
     if (disk->fops == &nvme_bdev_ops)
         return nvme_get_ns_from_dev(dev)->head;
     else
         return disk->private_data;
 }
 
 static ssize_t wwid_show(struct device *dev, struct device_attribute *attr,
         char *buf)
 {
     struct nvme_ns_head *head = dev_to_ns_head(dev);
     struct nvme_ns_ids *ids = &head->ids;
     struct nvme_subsystem *subsys = head->subsys;
     int serial_len = sizeof(subsys->serial);
     int model_len = sizeof(subsys->model);
 
     if (!uuid_is_null(&ids->uuid))
         return sysfs_emit(buf, "uuid.%pU\n", &ids->uuid);
 
     if (memchr_inv(ids->nguid, 0, sizeof(ids->nguid)))
         return sysfs_emit(buf, "eui.%16phN\n", ids->nguid);
 
     if (memchr_inv(ids->eui64, 0, sizeof(ids->eui64)))
         return sysfs_emit(buf, "eui.%8phN\n", ids->eui64);
 
     while (serial_len > 0 && (subsys->serial[serial_len - 1] == ' ' ||
                   subsys->serial[serial_len - 1] == '\0'))
         serial_len--;
     while (model_len > 0 && (subsys->model[model_len - 1] == ' ' ||
                  subsys->model[model_len - 1] == '\0'))
         model_len--;
 
     return sysfs_emit(buf, "nvme.%04x-%*phN-%*phN-%08x\n", subsys->vendor_id,
         serial_len, subsys->serial, model_len, subsys->model,
         head->ns_id);
 }
 static DEVICE_ATTR_RO(wwid);
 
 static ssize_t nguid_show(struct device *dev, struct device_attribute *attr,
         char *buf)
 {
     return sysfs_emit(buf, "%pU\n", dev_to_ns_head(dev)->ids.nguid);
 }
 static DEVICE_ATTR_RO(nguid);
 
 static ssize_t uuid_show(struct device *dev, struct device_attribute *attr,
         char *buf)
 {
     struct nvme_ns_ids *ids = &dev_to_ns_head(dev)->ids;
 
     /* For backward compatibility expose the NGUID to userspace if
      * we have no UUID set
      */
     if (uuid_is_null(&ids->uuid)) {
         dev_warn_ratelimited(dev,
             "No UUID available providing old NGUID\n");
         return sysfs_emit(buf, "%pU\n", ids->nguid);
     }
     return sysfs_emit(buf, "%pU\n", &ids->uuid);
 }
 static DEVICE_ATTR_RO(uuid);
 
 static ssize_t eui_show(struct device *dev, struct device_attribute *attr,
         char *buf)
 {
     return sysfs_emit(buf, "%8ph\n", dev_to_ns_head(dev)->ids.eui64);
 }
 static DEVICE_ATTR_RO(eui);
 
 static ssize_t nsid_show(struct device *dev, struct device_attribute *attr,
         char *buf)
 {
     return sysfs_emit(buf, "%d\n", dev_to_ns_head(dev)->ns_id);
 }
 static DEVICE_ATTR_RO(nsid);
 
 static struct attribute *nvme_ns_id_attrs[] = {
     &dev_attr_wwid.attr,
     &dev_attr_uuid.attr,
     &dev_attr_nguid.attr,
     &dev_attr_eui.attr,
     &dev_attr_nsid.attr,
 #ifdef CONFIG_NVME_MULTIPATH
     &dev_attr_ana_grpid.attr,
     &dev_attr_ana_state.attr,
 #endif
     NULL,
 };
 
 static umode_t nvme_ns_id_attrs_are_visible(struct kobject *kobj,
         struct attribute *a, int n)
 {
     struct device *dev = container_of(kobj, struct device, kobj);
     struct nvme_ns_ids *ids = &dev_to_ns_head(dev)->ids;
 
     if (a == &dev_attr_uuid.attr) {
         if (uuid_is_null(&ids->uuid) &&
             !memchr_inv(ids->nguid, 0, sizeof(ids->nguid)))
             return 0;
     }
     if (a == &dev_attr_nguid.attr) {
         if (!memchr_inv(ids->nguid, 0, sizeof(ids->nguid)))
             return 0;
     }
     if (a == &dev_attr_eui.attr) {
         if (!memchr_inv(ids->eui64, 0, sizeof(ids->eui64)))
             return 0;
     }
 #ifdef CONFIG_NVME_MULTIPATH
     if (a == &dev_attr_ana_grpid.attr || a == &dev_attr_ana_state.attr) {
         if (dev_to_disk(dev)->fops != &nvme_bdev_ops) /* per-path attr */
             return 0;
         if (!nvme_ctrl_use_ana(nvme_get_ns_from_dev(dev)->ctrl))
             return 0;
     }
 #endif
     return a->mode;
 }
 
 static const struct attribute_group nvme_ns_id_attr_group = {
     .attrs      = nvme_ns_id_attrs,
     .is_visible = nvme_ns_id_attrs_are_visible,
 };
 
 const struct attribute_group *nvme_ns_id_attr_groups[] = {
     &nvme_ns_id_attr_group,
     NULL,
 };
 
 #define nvme_show_str_function(field)                       \
 static ssize_t  field##_show(struct device *dev,                \
                 struct device_attribute *attr, char *buf)       \
 {                                       \
         struct nvme_ctrl *ctrl = dev_get_drvdata(dev);              \
         return sysfs_emit(buf, "%.*s\n",                    \
         (int)sizeof(ctrl->subsys->field), ctrl->subsys->field);     \
 }                                       \
 static DEVICE_ATTR(field, S_IRUGO, field##_show, NULL);
 
 nvme_show_str_function(model);
 nvme_show_str_function(serial);
 nvme_show_str_function(firmware_rev);
 
 #define nvme_show_int_function(field)                       \
 static ssize_t  field##_show(struct device *dev,                \
                 struct device_attribute *attr, char *buf)       \
 {                                       \
         struct nvme_ctrl *ctrl = dev_get_drvdata(dev);              \
         return sysfs_emit(buf, "%d\n", ctrl->field);                \
 }                                       \
 static DEVICE_ATTR(field, S_IRUGO, field##_show, NULL);
 
 nvme_show_int_function(cntlid);
 nvme_show_int_function(numa_node);
 nvme_show_int_function(queue_count);
 nvme_show_int_function(sqsize);
 nvme_show_int_function(kato);
 
 static ssize_t nvme_sysfs_delete(struct device *dev,
                 struct device_attribute *attr, const char *buf,
                 size_t count)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
 
     if (device_remove_file_self(dev, attr))
         nvme_delete_ctrl_sync(ctrl);
     return count;
 }
 static DEVICE_ATTR(delete_controller, S_IWUSR, NULL, nvme_sysfs_delete);
 
 static ssize_t nvme_sysfs_show_transport(struct device *dev,
                      struct device_attribute *attr,
                      char *buf)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
 
     return sysfs_emit(buf, "%s\n", ctrl->ops->name);
 }
 static DEVICE_ATTR(transport, S_IRUGO, nvme_sysfs_show_transport, NULL);
 
 static ssize_t nvme_sysfs_show_state(struct device *dev,
                      struct device_attribute *attr,
                      char *buf)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
     static const char *const state_name[] = {
         [NVME_CTRL_NEW]     = "new",
         [NVME_CTRL_LIVE]    = "live",
         [NVME_CTRL_RESETTING]   = "resetting",
         [NVME_CTRL_CONNECTING]  = "connecting",
         [NVME_CTRL_DELETING]    = "deleting",
         [NVME_CTRL_DELETING_NOIO]= "deleting (no IO)",
         [NVME_CTRL_DEAD]    = "dead",
     };
 
     if ((unsigned)ctrl->state < ARRAY_SIZE(state_name) &&
         state_name[ctrl->state])
         return sysfs_emit(buf, "%s\n", state_name[ctrl->state]);
 
     return sysfs_emit(buf, "unknown state\n");
 }
 
 static DEVICE_ATTR(state, S_IRUGO, nvme_sysfs_show_state, NULL);
 
 static ssize_t nvme_sysfs_show_subsysnqn(struct device *dev,
                      struct device_attribute *attr,
                      char *buf)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
 
     return sysfs_emit(buf, "%s\n", ctrl->subsys->subnqn);
 }
 static DEVICE_ATTR(subsysnqn, S_IRUGO, nvme_sysfs_show_subsysnqn, NULL);
 
 static ssize_t nvme_sysfs_show_hostnqn(struct device *dev,
                     struct device_attribute *attr,
                     char *buf)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
 
     return sysfs_emit(buf, "%s\n", ctrl->opts->host->nqn);
 }
 static DEVICE_ATTR(hostnqn, S_IRUGO, nvme_sysfs_show_hostnqn, NULL);
 
 static ssize_t nvme_sysfs_show_hostid(struct device *dev,
                     struct device_attribute *attr,
                     char *buf)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
 
     return sysfs_emit(buf, "%pU\n", &ctrl->opts->host->id);
 }
 static DEVICE_ATTR(hostid, S_IRUGO, nvme_sysfs_show_hostid, NULL);
 
 static ssize_t nvme_sysfs_show_address(struct device *dev,
                      struct device_attribute *attr,
                      char *buf)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
 
     return ctrl->ops->get_address(ctrl, buf, PAGE_SIZE);
 }
 static DEVICE_ATTR(address, S_IRUGO, nvme_sysfs_show_address, NULL);
 
 static ssize_t nvme_ctrl_loss_tmo_show(struct device *dev,
         struct device_attribute *attr, char *buf)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
     struct nvmf_ctrl_options *opts = ctrl->opts;
 
     if (ctrl->opts->max_reconnects == -1)
         return sysfs_emit(buf, "off\n");
     return sysfs_emit(buf, "%d\n",
               opts->max_reconnects * opts->reconnect_delay);
 }
 
 static ssize_t nvme_ctrl_loss_tmo_store(struct device *dev,
         struct device_attribute *attr, const char *buf, size_t count)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
     struct nvmf_ctrl_options *opts = ctrl->opts;
     int ctrl_loss_tmo, err;
 
     err = kstrtoint(buf, 10, &ctrl_loss_tmo);
     if (err)
         return -EINVAL;
 
     if (ctrl_loss_tmo < 0)
         opts->max_reconnects = -1;
     else
         opts->max_reconnects = DIV_ROUND_UP(ctrl_loss_tmo,
                         opts->reconnect_delay);
     return count;
 }
 static DEVICE_ATTR(ctrl_loss_tmo, S_IRUGO | S_IWUSR,
     nvme_ctrl_loss_tmo_show, nvme_ctrl_loss_tmo_store);
 
 static ssize_t nvme_ctrl_reconnect_delay_show(struct device *dev,
         struct device_attribute *attr, char *buf)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
 
     if (ctrl->opts->reconnect_delay == -1)
         return sysfs_emit(buf, "off\n");
     return sysfs_emit(buf, "%d\n", ctrl->opts->reconnect_delay);
 }
 
 static ssize_t nvme_ctrl_reconnect_delay_store(struct device *dev,
         struct device_attribute *attr, const char *buf, size_t count)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
     unsigned int v;
     int err;
 
     err = kstrtou32(buf, 10, &v);
     if (err)
         return err;
 
     ctrl->opts->reconnect_delay = v;
     return count;
 }
 static DEVICE_ATTR(reconnect_delay, S_IRUGO | S_IWUSR,
     nvme_ctrl_reconnect_delay_show, nvme_ctrl_reconnect_delay_store);
 
 static ssize_t nvme_ctrl_fast_io_fail_tmo_show(struct device *dev,
         struct device_attribute *attr, char *buf)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
 
     if (ctrl->opts->fast_io_fail_tmo == -1)
         return sysfs_emit(buf, "off\n");
     return sysfs_emit(buf, "%d\n", ctrl->opts->fast_io_fail_tmo);
 }
 
 static ssize_t nvme_ctrl_fast_io_fail_tmo_store(struct device *dev,
         struct device_attribute *attr, const char *buf, size_t count)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
     struct nvmf_ctrl_options *opts = ctrl->opts;
     int fast_io_fail_tmo, err;
 
     err = kstrtoint(buf, 10, &fast_io_fail_tmo);
     if (err)
         return -EINVAL;
 
     if (fast_io_fail_tmo < 0)
         opts->fast_io_fail_tmo = -1;
     else
         opts->fast_io_fail_tmo = fast_io_fail_tmo;
     return count;
 }
 static DEVICE_ATTR(fast_io_fail_tmo, S_IRUGO | S_IWUSR,
     nvme_ctrl_fast_io_fail_tmo_show, nvme_ctrl_fast_io_fail_tmo_store);
 
 static ssize_t cntrltype_show(struct device *dev,
                   struct device_attribute *attr, char *buf)
 {
     static const char * const type[] = {
         [NVME_CTRL_IO] = "io\n",
         [NVME_CTRL_DISC] = "discovery\n",
         [NVME_CTRL_ADMIN] = "admin\n",
     };
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
 
     if (ctrl->cntrltype > NVME_CTRL_ADMIN || !type[ctrl->cntrltype])
         return sysfs_emit(buf, "reserved\n");
 
     return sysfs_emit(buf, type[ctrl->cntrltype]);
 }
 static DEVICE_ATTR_RO(cntrltype);
 
 static ssize_t dctype_show(struct device *dev,
                struct device_attribute *attr, char *buf)
 {
     static const char * const type[] = {
         [NVME_DCTYPE_NOT_REPORTED] = "none\n",
         [NVME_DCTYPE_DDC] = "ddc\n",
         [NVME_DCTYPE_CDC] = "cdc\n",
     };
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
 
     if (ctrl->dctype > NVME_DCTYPE_CDC || !type[ctrl->dctype])
         return sysfs_emit(buf, "reserved\n");
 
     return sysfs_emit(buf, type[ctrl->dctype]);
 }
 static DEVICE_ATTR_RO(dctype);
 
 #ifdef CONFIG_NVME_AUTH
 static ssize_t nvme_ctrl_dhchap_secret_show(struct device *dev,
         struct device_attribute *attr, char *buf)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
     struct nvmf_ctrl_options *opts = ctrl->opts;
 
     if (!opts->dhchap_secret)
         return sysfs_emit(buf, "none\n");
     return sysfs_emit(buf, "%s\n", opts->dhchap_secret);
 }
 
 static ssize_t nvme_ctrl_dhchap_secret_store(struct device *dev,
         struct device_attribute *attr, const char *buf, size_t count)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
     struct nvmf_ctrl_options *opts = ctrl->opts;
     char *dhchap_secret;
 
     if (!ctrl->opts->dhchap_secret)
         return -EINVAL;
     if (count < 7)
         return -EINVAL;
     if (memcmp(buf, "DHHC-1:", 7))
         return -EINVAL;
 
     dhchap_secret = kzalloc(count + 1, GFP_KERNEL);
     if (!dhchap_secret)
         return -ENOMEM;
     memcpy(dhchap_secret, buf, count);
     nvme_auth_stop(ctrl);
     if (strcmp(dhchap_secret, opts->dhchap_secret)) {
         int ret;
 
         ret = nvme_auth_generate_key(dhchap_secret, &ctrl->host_key);
         if (ret)
             return ret;
         kfree(opts->dhchap_secret);
         opts->dhchap_secret = dhchap_secret;
         /* Key has changed; re-authentication with new key */
         nvme_auth_reset(ctrl);
     }
     /* Start re-authentication */
     dev_info(ctrl->device, "re-authenticating controller\n");
     queue_work(nvme_wq, &ctrl->dhchap_auth_work);
 
     return count;
 }
 static DEVICE_ATTR(dhchap_secret, S_IRUGO | S_IWUSR,
     nvme_ctrl_dhchap_secret_show, nvme_ctrl_dhchap_secret_store);
 
 static ssize_t nvme_ctrl_dhchap_ctrl_secret_show(struct device *dev,
         struct device_attribute *attr, char *buf)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
     struct nvmf_ctrl_options *opts = ctrl->opts;
 
     if (!opts->dhchap_ctrl_secret)
         return sysfs_emit(buf, "none\n");
     return sysfs_emit(buf, "%s\n", opts->dhchap_ctrl_secret);
 }
 
 static ssize_t nvme_ctrl_dhchap_ctrl_secret_store(struct device *dev,
         struct device_attribute *attr, const char *buf, size_t count)
 {
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
     struct nvmf_ctrl_options *opts = ctrl->opts;
     char *dhchap_secret;
 
     if (!ctrl->opts->dhchap_ctrl_secret)
         return -EINVAL;
     if (count < 7)
         return -EINVAL;
     if (memcmp(buf, "DHHC-1:", 7))
         return -EINVAL;
 
     dhchap_secret = kzalloc(count + 1, GFP_KERNEL);
     if (!dhchap_secret)
         return -ENOMEM;
     memcpy(dhchap_secret, buf, count);
     nvme_auth_stop(ctrl);
     if (strcmp(dhchap_secret, opts->dhchap_ctrl_secret)) {
         int ret;
 
         ret = nvme_auth_generate_key(dhchap_secret, &ctrl->ctrl_key);
         if (ret)
             return ret;
         kfree(opts->dhchap_ctrl_secret);
         opts->dhchap_ctrl_secret = dhchap_secret;
         /* Key has changed; re-authentication with new key */
         nvme_auth_reset(ctrl);
     }
     /* Start re-authentication */
     dev_info(ctrl->device, "re-authenticating controller\n");
     queue_work(nvme_wq, &ctrl->dhchap_auth_work);
 
     return count;
 }
 static DEVICE_ATTR(dhchap_ctrl_secret, S_IRUGO | S_IWUSR,
     nvme_ctrl_dhchap_ctrl_secret_show, nvme_ctrl_dhchap_ctrl_secret_store);
 #endif
 
 static struct attribute *nvme_dev_attrs[] = {
     &dev_attr_reset_controller.attr,
     &dev_attr_rescan_controller.attr,
     &dev_attr_model.attr,
     &dev_attr_serial.attr,
     &dev_attr_firmware_rev.attr,
     &dev_attr_cntlid.attr,
     &dev_attr_delete_controller.attr,
     &dev_attr_transport.attr,
     &dev_attr_subsysnqn.attr,
     &dev_attr_address.attr,
     &dev_attr_state.attr,
     &dev_attr_numa_node.attr,
     &dev_attr_queue_count.attr,
     &dev_attr_sqsize.attr,
     &dev_attr_hostnqn.attr,
     &dev_attr_hostid.attr,
     &dev_attr_ctrl_loss_tmo.attr,
     &dev_attr_reconnect_delay.attr,
     &dev_attr_fast_io_fail_tmo.attr,
     &dev_attr_kato.attr,
     &dev_attr_cntrltype.attr,
     &dev_attr_dctype.attr,
 #ifdef CONFIG_NVME_AUTH
     &dev_attr_dhchap_secret.attr,
     &dev_attr_dhchap_ctrl_secret.attr,
 #endif
     NULL
 };
 
 static umode_t nvme_dev_attrs_are_visible(struct kobject *kobj,
         struct attribute *a, int n)
 {
     struct device *dev = container_of(kobj, struct device, kobj);
     struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
 
     if (a == &dev_attr_delete_controller.attr && !ctrl->ops->delete_ctrl)
         return 0;
     if (a == &dev_attr_address.attr && !ctrl->ops->get_address)
         return 0;
     if (a == &dev_attr_hostnqn.attr && !ctrl->opts)
         return 0;
     if (a == &dev_attr_hostid.attr && !ctrl->opts)
         return 0;
     if (a == &dev_attr_ctrl_loss_tmo.attr && !ctrl->opts)
         return 0;
     if (a == &dev_attr_reconnect_delay.attr && !ctrl->opts)
         return 0;
     if (a == &dev_attr_fast_io_fail_tmo.attr && !ctrl->opts)
         return 0;
 #ifdef CONFIG_NVME_AUTH
     if (a == &dev_attr_dhchap_secret.attr && !ctrl->opts)
         return 0;
     if (a == &dev_attr_dhchap_ctrl_secret.attr && !ctrl->opts)
         return 0;
 #endif
 
     return a->mode;
 }
 
 static const struct attribute_group nvme_dev_attrs_group = {
     .attrs      = nvme_dev_attrs,
     .is_visible = nvme_dev_attrs_are_visible,
 };
 
 static const struct attribute_group *nvme_dev_attr_groups[] = {
     &nvme_dev_attrs_group,
     NULL,
 };
 
 static struct nvme_ns_head *nvme_find_ns_head(struct nvme_ctrl *ctrl,
         unsigned nsid)
 {
     struct nvme_ns_head *h;
 
     lockdep_assert_held(&ctrl->subsys->lock);
 
     list_for_each_entry(h, &ctrl->subsys->nsheads, entry) {
         /*
          * Private namespaces can share NSIDs under some conditions.
          * In that case we can't use the same ns_head for namespaces
          * with the same NSID.
          */
         if (h->ns_id != nsid || !nvme_is_unique_nsid(ctrl, h))
             continue;
         if (!list_empty(&h->list) && nvme_tryget_ns_head(h))
             return h;
     }
 
     return NULL;
 }
 
 static int nvme_subsys_check_duplicate_ids(struct nvme_subsystem *subsys,
         struct nvme_ns_ids *ids)
 {
     bool has_uuid = !uuid_is_null(&ids->uuid);
     bool has_nguid = memchr_inv(ids->nguid, 0, sizeof(ids->nguid));
     bool has_eui64 = memchr_inv(ids->eui64, 0, sizeof(ids->eui64));
     struct nvme_ns_head *h;
 
     lockdep_assert_held(&subsys->lock);
 
     list_for_each_entry(h, &subsys->nsheads, entry) {
         if (has_uuid && uuid_equal(&ids->uuid, &h->ids.uuid))
             return -EINVAL;
         if (has_nguid &&
             memcmp(&ids->nguid, &h->ids.nguid, sizeof(ids->nguid)) == 0)
             return -EINVAL;
         if (has_eui64 &&
             memcmp(&ids->eui64, &h->ids.eui64, sizeof(ids->eui64)) == 0)
             return -EINVAL;
     }
 
     return 0;
 }
 
 static void nvme_cdev_rel(struct device *dev)
 {
     ida_free(&nvme_ns_chr_minor_ida, MINOR(dev->devt));
 }
 
 void nvme_cdev_del(struct cdev *cdev, struct device *cdev_device)
 {
     cdev_device_del(cdev, cdev_device);
     put_device(cdev_device);
 }
 
 int nvme_cdev_add(struct cdev *cdev, struct device *cdev_device,
         const struct file_operations *fops, struct module *owner)
 {
     int minor, ret;
 
     minor = ida_alloc(&nvme_ns_chr_minor_ida, GFP_KERNEL);
     if (minor < 0)
         return minor;
     cdev_device->devt = MKDEV(MAJOR(nvme_ns_chr_devt), minor);
     cdev_device->class = nvme_ns_chr_class;
     cdev_device->release = nvme_cdev_rel;
     device_initialize(cdev_device);
     cdev_init(cdev, fops);
     cdev->owner = owner;
     ret = cdev_device_add(cdev, cdev_device);
     if (ret)
         put_device(cdev_device);
 
     return ret;
 }
 
 static int nvme_ns_chr_open(struct inode *inode, struct file *file)
 {
     return nvme_ns_open(container_of(inode->i_cdev, struct nvme_ns, cdev));
 }
 
 static int nvme_ns_chr_release(struct inode *inode, struct file *file)
 {
     nvme_ns_release(container_of(inode->i_cdev, struct nvme_ns, cdev));
     return 0;
 }
 
 static const struct file_operations nvme_ns_chr_fops = {
     .owner      = THIS_MODULE,
     .open       = nvme_ns_chr_open,
     .release    = nvme_ns_chr_release,
     .unlocked_ioctl = nvme_ns_chr_ioctl,
     .compat_ioctl   = compat_ptr_ioctl,
     .uring_cmd  = nvme_ns_chr_uring_cmd,
 };
 
 static int nvme_add_ns_cdev(struct nvme_ns *ns)
 {
     int ret;
 
     ns->cdev_device.parent = ns->ctrl->device;
     ret = dev_set_name(&ns->cdev_device, "ng%dn%d",
                ns->ctrl->instance, ns->head->instance);
     if (ret)
         return ret;
 
     return nvme_cdev_add(&ns->cdev, &ns->cdev_device, &nvme_ns_chr_fops,
                  ns->ctrl->ops->module);
 }
 
 static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ctrl *ctrl,
         struct nvme_ns_info *info)
 {
     struct nvme_ns_head *head;
     size_t size = sizeof(*head);
     int ret = -ENOMEM;
 
 #ifdef CONFIG_NVME_MULTIPATH
     size += num_possible_nodes() * sizeof(struct nvme_ns *);
 #endif
 
     head = kzalloc(size, GFP_KERNEL);
     if (!head)
         goto out;
     ret = ida_alloc_min(&ctrl->subsys->ns_ida, 1, GFP_KERNEL);
     if (ret < 0)
         goto out_free_head;
     head->instance = ret;
     INIT_LIST_HEAD(&head->list);
     ret = init_srcu_struct(&head->srcu);
     if (ret)
         goto out_ida_remove;
     head->subsys = ctrl->subsys;
     head->ns_id = info->nsid;
     head->ids = info->ids;
     head->shared = info->is_shared;
     kref_init(&head->ref);
 
     if (head->ids.csi) {
         ret = nvme_get_effects_log(ctrl, head->ids.csi, &head->effects);
         if (ret)
             goto out_cleanup_srcu;
     } else
         head->effects = ctrl->effects;
 
     ret = nvme_mpath_alloc_disk(ctrl, head);
     if (ret)
         goto out_cleanup_srcu;
 
     list_add_tail(&head->entry, &ctrl->subsys->nsheads);
 
     kref_get(&ctrl->subsys->ref);
 
     return head;
 out_cleanup_srcu:
     cleanup_srcu_struct(&head->srcu);
 out_ida_remove:
     ida_free(&ctrl->subsys->ns_ida, head->instance);
 out_free_head:
     kfree(head);
 out:
     if (ret > 0)
         ret = blk_status_to_errno(nvme_error_status(ret));
     return ERR_PTR(ret);
 }
 
 static int nvme_global_check_duplicate_ids(struct nvme_subsystem *this,
         struct nvme_ns_ids *ids)
 {
     struct nvme_subsystem *s;
     int ret = 0;
 
     /*
      * Note that this check is racy as we try to avoid holding the global
      * lock over the whole ns_head creation.  But it is only intended as
      * a sanity check anyway.
      */
     mutex_lock(&nvme_subsystems_lock);
     list_for_each_entry(s, &nvme_subsystems, entry) {
         if (s == this)
             continue;
         mutex_lock(&s->lock);
         ret = nvme_subsys_check_duplicate_ids(s, ids);
         mutex_unlock(&s->lock);
         if (ret)
             break;
     }
     mutex_unlock(&nvme_subsystems_lock);
 
     return ret;
 }
 
 static int nvme_init_ns_head(struct nvme_ns *ns, struct nvme_ns_info *info)
 {
     struct nvme_ctrl *ctrl = ns->ctrl;
     struct nvme_ns_head *head = NULL;
     int ret;
 
     ret = nvme_global_check_duplicate_ids(ctrl->subsys, &info->ids);
     if (ret) {
         dev_err(ctrl->device,
             "globally duplicate IDs for nsid %d\n", info->nsid);
         nvme_print_device_info(ctrl);
         return ret;
     }
 
     mutex_lock(&ctrl->subsys->lock);
     head = nvme_find_ns_head(ctrl, info->nsid);
     if (!head) {
         ret = nvme_subsys_check_duplicate_ids(ctrl->subsys, &info->ids);
         if (ret) {
             dev_err(ctrl->device,
                 "duplicate IDs in subsystem for nsid %d\n",
                 info->nsid);
             goto out_unlock;
         }
         head = nvme_alloc_ns_head(ctrl, info);
         if (IS_ERR(head)) {
             ret = PTR_ERR(head);
             goto out_unlock;
         }
     } else {
         ret = -EINVAL;
         if (!info->is_shared || !head->shared) {
             dev_err(ctrl->device,
                 "Duplicate unshared namespace %d\n",
                 info->nsid);
             goto out_put_ns_head;
         }
         if (!nvme_ns_ids_equal(&head->ids, &info->ids)) {
             dev_err(ctrl->device,
                 "IDs don't match for shared namespace %d\n",
                     info->nsid);
             goto out_put_ns_head;
         }
 
         if (!multipath && !list_empty(&head->list)) {
             dev_warn(ctrl->device,
                 "Found shared namespace %d, but multipathing not supported.\n",
                 info->nsid);
             dev_warn_once(ctrl->device,
                 "Support for shared namespaces without CONFIG_NVME_MULTIPATH is deprecated and will be removed in Linux 6.0\n.");
         }
     }
 
     list_add_tail_rcu(&ns->siblings, &head->list);
     ns->head = head;
     mutex_unlock(&ctrl->subsys->lock);
     return 0;
 
 out_put_ns_head:
     nvme_put_ns_head(head);
 out_unlock:
     mutex_unlock(&ctrl->subsys->lock);
     return ret;
 }
 
 struct nvme_ns *nvme_find_get_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 {
     struct nvme_ns *ns, *ret = NULL;
 
     down_read(&ctrl->namespaces_rwsem);
     list_for_each_entry(ns, &ctrl->namespaces, list) {
         if (ns->head->ns_id == nsid) {
             if (!nvme_get_ns(ns))
                 continue;
             ret = ns;
             break;
         }
         if (ns->head->ns_id > nsid)
             break;
     }
     up_read(&ctrl->namespaces_rwsem);
     return ret;
 }
 EXPORT_SYMBOL_NS_GPL(nvme_find_get_ns, NVME_TARGET_PASSTHRU);
 
 /*
  * Add the namespace to the controller list while keeping the list ordered.
  */
 static void nvme_ns_add_to_ctrl_list(struct nvme_ns *ns)
 {
     struct nvme_ns *tmp;
 
     list_for_each_entry_reverse(tmp, &ns->ctrl->namespaces, list) {
         if (tmp->head->ns_id < ns->head->ns_id) {
             list_add(&ns->list, &tmp->list);
             return;
         }
     }
     list_add(&ns->list, &ns->ctrl->namespaces);
 }
 
 static void nvme_alloc_ns(struct nvme_ctrl *ctrl, struct nvme_ns_info *info)
 {
     struct nvme_ns *ns;
     struct gendisk *disk;
     int node = ctrl->numa_node;
 
     ns = kzalloc_node(sizeof(*ns), GFP_KERNEL, node);
     if (!ns)
         return;
 
     disk = blk_mq_alloc_disk(ctrl->tagset, ns);
     if (IS_ERR(disk))
         goto out_free_ns;
     disk->fops = &nvme_bdev_ops;
     disk->private_data = ns;
 
     ns->disk = disk;
     ns->queue = disk->queue;
 
     if (ctrl->opts && ctrl->opts->data_digest)
         blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES, ns->queue);
 
     blk_queue_flag_set(QUEUE_FLAG_NONROT, ns->queue);
     if (ctrl->ops->supports_pci_p2pdma &&
         ctrl->ops->supports_pci_p2pdma(ctrl))
         blk_queue_flag_set(QUEUE_FLAG_PCI_P2PDMA, ns->queue);
 
     ns->ctrl = ctrl;
     kref_init(&ns->kref);
 
     if (nvme_init_ns_head(ns, info))
         goto out_cleanup_disk;
 
     /*
      * If multipathing is enabled, the device name for all disks and not
      * just those that represent shared namespaces needs to be based on the
      * subsystem instance.  Using the controller instance for private
      * namespaces could lead to naming collisions between shared and private
      * namespaces if they don't use a common numbering scheme.
      *
      * If multipathing is not enabled, disk names must use the controller
      * instance as shared namespaces will show up as multiple block
      * devices.
      */
     if (ns->head->disk) {
         sprintf(disk->disk_name, "nvme%dc%dn%d", ctrl->subsys->instance,
             ctrl->instance, ns->head->instance);
         disk->flags |= GENHD_FL_HIDDEN;
     } else if (multipath) {
         sprintf(disk->disk_name, "nvme%dn%d", ctrl->subsys->instance,
             ns->head->instance);
     } else {
         sprintf(disk->disk_name, "nvme%dn%d", ctrl->instance,
             ns->head->instance);
     }
 
     if (nvme_update_ns_info(ns, info))
         goto out_unlink_ns;
 
     down_write(&ctrl->namespaces_rwsem);
     nvme_ns_add_to_ctrl_list(ns);
     up_write(&ctrl->namespaces_rwsem);
     nvme_get_ctrl(ctrl);
 
     if (device_add_disk(ctrl->device, ns->disk, nvme_ns_id_attr_groups))
         goto out_cleanup_ns_from_list;
 
     if (!nvme_ns_head_multipath(ns->head))
         nvme_add_ns_cdev(ns);
 
     nvme_mpath_add_disk(ns, info->anagrpid);
     nvme_fault_inject_init(&ns->fault_inject, ns->disk->disk_name);
 
     return;
 
  out_cleanup_ns_from_list:
     nvme_put_ctrl(ctrl);
     down_write(&ctrl->namespaces_rwsem);
     list_del_init(&ns->list);
     up_write(&ctrl->namespaces_rwsem);
  out_unlink_ns:
     mutex_lock(&ctrl->subsys->lock);
     list_del_rcu(&ns->siblings);
     if (list_empty(&ns->head->list))
         list_del_init(&ns->head->entry);
     mutex_unlock(&ctrl->subsys->lock);
     nvme_put_ns_head(ns->head);
  out_cleanup_disk:
     put_disk(disk);
  out_free_ns:
     kfree(ns);
 }
 
 static void nvme_ns_remove(struct nvme_ns *ns)
 {
     bool last_path = false;
 
     if (test_and_set_bit(NVME_NS_REMOVING, &ns->flags))
         return;
 
     clear_bit(NVME_NS_READY, &ns->flags);
     set_capacity(ns->disk, 0);
     nvme_fault_inject_fini(&ns->fault_inject);
 
     /*
      * Ensure that !NVME_NS_READY is seen by other threads to prevent
      * this ns going back into current_path.
      */
     synchronize_srcu(&ns->head->srcu);
 
     /* wait for concurrent submissions */
     if (nvme_mpath_clear_current_path(ns))
         synchronize_srcu(&ns->head->srcu);
 
     mutex_lock(&ns->ctrl->subsys->lock);
     list_del_rcu(&ns->siblings);
     if (list_empty(&ns->head->list)) {
         list_del_init(&ns->head->entry);
         last_path = true;
     }
     mutex_unlock(&ns->ctrl->subsys->lock);
 
     /* guarantee not available in head->list */
     synchronize_rcu();
 
     if (!nvme_ns_head_multipath(ns->head))
         nvme_cdev_del(&ns->cdev, &ns->cdev_device);
     del_gendisk(ns->disk);
 
     down_write(&ns->ctrl->namespaces_rwsem);
     list_del_init(&ns->list);
     up_write(&ns->ctrl->namespaces_rwsem);
 
     if (last_path)
         nvme_mpath_shutdown_disk(ns->head);
     nvme_put_ns(ns);
 }
 
 static void nvme_ns_remove_by_nsid(struct nvme_ctrl *ctrl, u32 nsid)
 {
     struct nvme_ns *ns = nvme_find_get_ns(ctrl, nsid);
 
     if (ns) {
         nvme_ns_remove(ns);
         nvme_put_ns(ns);
     }
 }
 
 static void nvme_validate_ns(struct nvme_ns *ns, struct nvme_ns_info *info)
 {
     int ret = NVME_SC_INVALID_NS | NVME_SC_DNR;
 
     if (test_bit(NVME_NS_DEAD, &ns->flags))
         goto out;
 
     ret = NVME_SC_INVALID_NS | NVME_SC_DNR;
     if (!nvme_ns_ids_equal(&ns->head->ids, &info->ids)) {
         dev_err(ns->ctrl->device,
             "identifiers changed for nsid %d\n", ns->head->ns_id);
         goto out;
     }
 
     ret = nvme_update_ns_info(ns, info);
 out:
     /*
      * Only remove the namespace if we got a fatal error back from the
      * device, otherwise ignore the error and just move on.
      *
      * TODO: we should probably schedule a delayed retry here.
      */
     if (ret > 0 && (ret & NVME_SC_DNR))
         nvme_ns_remove(ns);
 }
 
 static void nvme_scan_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 {
     struct nvme_ns_info info = { .nsid = nsid };
     struct nvme_ns *ns;
 
     if (nvme_identify_ns_descs(ctrl, &info))
         return;
 
     if (info.ids.csi != NVME_CSI_NVM && !nvme_multi_css(ctrl)) {
         dev_warn(ctrl->device,
             "command set not reported for nsid: %d\n", nsid);
         return;
     }
 
     /*
      * If available try to use the Command Set Idependent Identify Namespace
      * data structure to find all the generic information that is needed to
      * set up a namespace.  If not fall back to the legacy version.
      */
     if ((ctrl->cap & NVME_CAP_CRMS_CRIMS) ||
         (info.ids.csi != NVME_CSI_NVM && info.ids.csi != NVME_CSI_ZNS)) {
         if (nvme_ns_info_from_id_cs_indep(ctrl, &info))
             return;
     } else {
         if (nvme_ns_info_from_identify(ctrl, &info))
             return;
     }
 
     /*
      * Ignore the namespace if it is not ready. We will get an AEN once it
      * becomes ready and restart the scan.
      */
     if (!info.is_ready)
         return;
 
     ns = nvme_find_get_ns(ctrl, nsid);
     if (ns) {
         nvme_validate_ns(ns, &info);
         nvme_put_ns(ns);
     } else {
         nvme_alloc_ns(ctrl, &info);
     }
 }
 
 static void nvme_remove_invalid_namespaces(struct nvme_ctrl *ctrl,
                     unsigned nsid)
 {
     struct nvme_ns *ns, *next;
     LIST_HEAD(rm_list);
 
     down_write(&ctrl->namespaces_rwsem);
     list_for_each_entry_safe(ns, next, &ctrl->namespaces, list) {
         if (ns->head->ns_id > nsid || test_bit(NVME_NS_DEAD, &ns->flags))
             list_move_tail(&ns->list, &rm_list);
     }
     up_write(&ctrl->namespaces_rwsem);
 
     list_for_each_entry_safe(ns, next, &rm_list, list)
         nvme_ns_remove(ns);
 
 }
 
 static int nvme_scan_ns_list(struct nvme_ctrl *ctrl)
 {
     const int nr_entries = NVME_IDENTIFY_DATA_SIZE / sizeof(__le32);
     __le32 *ns_list;
     u32 prev = 0;
     int ret = 0, i;
 
     if (nvme_ctrl_limited_cns(ctrl))
         return -EOPNOTSUPP;
 
     ns_list = kzalloc(NVME_IDENTIFY_DATA_SIZE, GFP_KERNEL);
     if (!ns_list)
         return -ENOMEM;
 
     for (;;) {
         struct nvme_command cmd = {
             .identify.opcode    = nvme_admin_identify,
             .identify.cns       = NVME_ID_CNS_NS_ACTIVE_LIST,
             .identify.nsid      = cpu_to_le32(prev),
         };
 
         ret = nvme_submit_sync_cmd(ctrl->admin_q, &cmd, ns_list,
                         NVME_IDENTIFY_DATA_SIZE);
         if (ret) {
             dev_warn(ctrl->device,
                 "Identify NS List failed (status=0x%x)\n", ret);
             goto free;
         }
 
         for (i = 0; i < nr_entries; i++) {
             u32 nsid = le32_to_cpu(ns_list[i]);
 
             if (!nsid)  /* end of the list? */
                 goto out;
             nvme_scan_ns(ctrl, nsid);
             while (++prev < nsid)
                 nvme_ns_remove_by_nsid(ctrl, prev);
         }
     }
  out:
     nvme_remove_invalid_namespaces(ctrl, prev);
  free:
     kfree(ns_list);
     return ret;
 }
 
 static void nvme_scan_ns_sequential(struct nvme_ctrl *ctrl)
 {
     struct nvme_id_ctrl *id;
     u32 nn, i;
 
     if (nvme_identify_ctrl(ctrl, &id))
         return;
     nn = le32_to_cpu(id->nn);
     kfree(id);
 
     for (i = 1; i <= nn; i++)
         nvme_scan_ns(ctrl, i);
 
     nvme_remove_invalid_namespaces(ctrl, nn);
 }
 
 static void nvme_clear_changed_ns_log(struct nvme_ctrl *ctrl)
 {
     size_t log_size = NVME_MAX_CHANGED_NAMESPACES * sizeof(__le32);
     __le32 *log;
     int error;
 
     log = kzalloc(log_size, GFP_KERNEL);
     if (!log)
         return;
 
     /*
      * We need to read the log to clear the AEN, but we don't want to rely
      * on it for the changed namespace information as userspace could have
      * raced with us in reading the log page, which could cause us to miss
      * updates.
      */
     error = nvme_get_log(ctrl, NVME_NSID_ALL, NVME_LOG_CHANGED_NS, 0,
             NVME_CSI_NVM, log, log_size, 0);
     if (error)
         dev_warn(ctrl->device,
             "reading changed ns log failed: %d\n", error);
 
     kfree(log);
 }
 
 static void nvme_scan_work(struct work_struct *work)
 {
     struct nvme_ctrl *ctrl =
         container_of(work, struct nvme_ctrl, scan_work);
     int ret;
 
     /* No tagset on a live ctrl means IO queues could not created */
     if (ctrl->state != NVME_CTRL_LIVE || !ctrl->tagset)
         return;
 
     /*
      * Identify controller limits can change at controller reset due to
      * new firmware download, even though it is not common we cannot ignore
      * such scenario. Controller's non-mdts limits are reported in the unit
      * of logical blocks that is dependent on the format of attached
      * namespace. Hence re-read the limits at the time of ns allocation.
      */
     ret = nvme_init_non_mdts_limits(ctrl);
     if (ret < 0) {
         dev_warn(ctrl->device,
             "reading non-mdts-limits failed: %d\n", ret);
         return;
     }
 
     if (test_and_clear_bit(NVME_AER_NOTICE_NS_CHANGED, &ctrl->events)) {
         dev_info(ctrl->device, "rescanning namespaces.\n");
         nvme_clear_changed_ns_log(ctrl);
     }
 
     mutex_lock(&ctrl->scan_lock);
     if (nvme_scan_ns_list(ctrl) != 0)
         nvme_scan_ns_sequential(ctrl);
     mutex_unlock(&ctrl->scan_lock);
 }
 
 /*
  * This function iterates the namespace list unlocked to allow recovery from
  * controller failure. It is up to the caller to ensure the namespace list is
  * not modified by scan work while this function is executing.
  */
 void nvme_remove_namespaces(struct nvme_ctrl *ctrl)
 {
     struct nvme_ns *ns, *next;
     LIST_HEAD(ns_list);
 
     /*
      * make sure to requeue I/O to all namespaces as these
      * might result from the scan itself and must complete
      * for the scan_work to make progress
      */
     nvme_mpath_clear_ctrl_paths(ctrl);
 
     /* prevent racing with ns scanning */
     flush_work(&ctrl->scan_work);
 
     /*
      * The dead states indicates the controller was not gracefully
      * disconnected. In that case, we won't be able to flush any data while
      * removing the namespaces' disks; fail all the queues now to avoid
      * potentially having to clean up the failed sync later.
      */
     if (ctrl->state == NVME_CTRL_DEAD)
         nvme_kill_queues(ctrl);
 
     /* this is a no-op when called from the controller reset handler */
     nvme_change_ctrl_state(ctrl, NVME_CTRL_DELETING_NOIO);
 
     down_write(&ctrl->namespaces_rwsem);
     list_splice_init(&ctrl->namespaces, &ns_list);
     up_write(&ctrl->namespaces_rwsem);
 
     list_for_each_entry_safe(ns, next, &ns_list, list)
         nvme_ns_remove(ns);
 }
 EXPORT_SYMBOL_GPL(nvme_remove_namespaces);
 
 static int nvme_class_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
     struct nvme_ctrl *ctrl =
         container_of(dev, struct nvme_ctrl, ctrl_device);
     struct nvmf_ctrl_options *opts = ctrl->opts;
     int ret;
 
     ret = add_uevent_var(env, "NVME_TRTYPE=%s", ctrl->ops->name);
     if (ret)
         return ret;
 
     if (opts) {
         ret = add_uevent_var(env, "NVME_TRADDR=%s", opts->traddr);
         if (ret)
             return ret;
 
         ret = add_uevent_var(env, "NVME_TRSVCID=%s",
                 opts->trsvcid ?: "none");
         if (ret)
             return ret;
 
         ret = add_uevent_var(env, "NVME_HOST_TRADDR=%s",
                 opts->host_traddr ?: "none");
         if (ret)
             return ret;
 
         ret = add_uevent_var(env, "NVME_HOST_IFACE=%s",
                 opts->host_iface ?: "none");
     }
     return ret;
 }
 
 static void nvme_change_uevent(struct nvme_ctrl *ctrl, char *envdata)
 {
     char *envp[2] = { envdata, NULL };
 
     kobject_uevent_env(&ctrl->device->kobj, KOBJ_CHANGE, envp);
 }
 
 static void nvme_aen_uevent(struct nvme_ctrl *ctrl)
 {
     char *envp[2] = { NULL, NULL };
     u32 aen_result = ctrl->aen_result;
 
     ctrl->aen_result = 0;
     if (!aen_result)
         return;
 
     envp[0] = kasprintf(GFP_KERNEL, "NVME_AEN=%#08x", aen_result);
     if (!envp[0])
         return;
     kobject_uevent_env(&ctrl->device->kobj, KOBJ_CHANGE, envp);
     kfree(envp[0]);
 }
 
 static void nvme_async_event_work(struct work_struct *work)
 {
     struct nvme_ctrl *ctrl =
         container_of(work, struct nvme_ctrl, async_event_work);
 
     nvme_aen_uevent(ctrl);
 
     /*
      * The transport drivers must guarantee AER submission here is safe by
      * flushing ctrl async_event_work after changing the controller state
      * from LIVE and before freeing the admin queue.
     */
     if (ctrl->state == NVME_CTRL_LIVE)
         ctrl->ops->submit_async_event(ctrl);
 }
 
 static bool nvme_ctrl_pp_status(struct nvme_ctrl *ctrl)
 {
 
     u32 csts;
 
     if (ctrl->ops->reg_read32(ctrl, NVME_REG_CSTS, &csts))
         return false;
 
     if (csts == ~0)
         return false;
 
     return ((ctrl->ctrl_config & NVME_CC_ENABLE) && (csts & NVME_CSTS_PP));
 }
 
 static void nvme_get_fw_slot_info(struct nvme_ctrl *ctrl)
 {
     struct nvme_fw_slot_info_log *log;
 
     log = kmalloc(sizeof(*log), GFP_KERNEL);
     if (!log)
         return;
 
     if (nvme_get_log(ctrl, NVME_NSID_ALL, NVME_LOG_FW_SLOT, 0, NVME_CSI_NVM,
             log, sizeof(*log), 0))
         dev_warn(ctrl->device, "Get FW SLOT INFO log error\n");
     kfree(log);
 }
 
 static void nvme_fw_act_work(struct work_struct *work)
 {
     struct nvme_ctrl *ctrl = container_of(work,
                 struct nvme_ctrl, fw_act_work);
     unsigned long fw_act_timeout;
 
     if (ctrl->mtfa)
         fw_act_timeout = jiffies +
                 msecs_to_jiffies(ctrl->mtfa * 100);
     else
         fw_act_timeout = jiffies +
                 msecs_to_jiffies(admin_timeout * 1000);
 
     nvme_stop_queues(ctrl);
     while (nvme_ctrl_pp_status(ctrl)) {
         if (time_after(jiffies, fw_act_timeout)) {
             dev_warn(ctrl->device,
                 "Fw activation timeout, reset controller\n");
             nvme_try_sched_reset(ctrl);
             return;
         }
         msleep(100);
     }
 
     if (!nvme_change_ctrl_state(ctrl, NVME_CTRL_LIVE))
         return;
 
     nvme_start_queues(ctrl);
     /* read FW slot information to clear the AER */
     nvme_get_fw_slot_info(ctrl);
 
     queue_work(nvme_wq, &ctrl->async_event_work);
 }
 
 static u32 nvme_aer_type(u32 result)
 {
     return result & 0x7;
 }
 
 static u32 nvme_aer_subtype(u32 result)
 {
     return (result & 0xff00) >> 8;
 }
 
 static bool nvme_handle_aen_notice(struct nvme_ctrl *ctrl, u32 result)
 {
     u32 aer_notice_type = nvme_aer_subtype(result);
     bool requeue = true;
 
     trace_nvme_async_event(ctrl, aer_notice_type);
 
     switch (aer_notice_type) {
     case NVME_AER_NOTICE_NS_CHANGED:
         set_bit(NVME_AER_NOTICE_NS_CHANGED, &ctrl->events);
         nvme_queue_scan(ctrl);
         break;
     case NVME_AER_NOTICE_FW_ACT_STARTING:
         /*
          * We are (ab)using the RESETTING state to prevent subsequent
          * recovery actions from interfering with the controller's
          * firmware activation.
          */
         if (nvme_change_ctrl_state(ctrl, NVME_CTRL_RESETTING)) {
             nvme_auth_stop(ctrl);
             requeue = false;
             queue_work(nvme_wq, &ctrl->fw_act_work);
         }
         break;
 #ifdef CONFIG_NVME_MULTIPATH
     case NVME_AER_NOTICE_ANA:
         if (!ctrl->ana_log_buf)
             break;
         queue_work(nvme_wq, &ctrl->ana_work);
         break;
 #endif
     case NVME_AER_NOTICE_DISC_CHANGED:
         ctrl->aen_result = result;
         break;
     default:
         dev_warn(ctrl->device, "async event result %08x\n", result);
     }
     return requeue;
 }
 
 static void nvme_handle_aer_persistent_error(struct nvme_ctrl *ctrl)
 {
     trace_nvme_async_event(ctrl, NVME_AER_ERROR);
     dev_warn(ctrl->device, "resetting controller due to AER\n");
     nvme_reset_ctrl(ctrl);
 }
 
 void nvme_complete_async_event(struct nvme_ctrl *ctrl, __le16 status,
         volatile union nvme_result *res)
 {
     u32 result = le32_to_cpu(res->u32);
     u32 aer_type = nvme_aer_type(result);
     u32 aer_subtype = nvme_aer_subtype(result);
     bool requeue = true;
 
     if (le16_to_cpu(status) >> 1 != NVME_SC_SUCCESS)
         return;
 
     switch (aer_type) {
     case NVME_AER_NOTICE:
         requeue = nvme_handle_aen_notice(ctrl, result);
         break;
     case NVME_AER_ERROR:
         /*
          * For a persistent internal error, don't run async_event_work
          * to submit a new AER. The controller reset will do it.
          */
         if (aer_subtype == NVME_AER_ERROR_PERSIST_INT_ERR) {
             nvme_handle_aer_persistent_error(ctrl);
             return;
         }
         fallthrough;
     case NVME_AER_SMART:
     case NVME_AER_CSS:
     case NVME_AER_VS:
         trace_nvme_async_event(ctrl, aer_type);
         ctrl->aen_result = result;
         break;
     default:
         break;
     }
 
     if (requeue)
         queue_work(nvme_wq, &ctrl->async_event_work);
 }
 EXPORT_SYMBOL_GPL(nvme_complete_async_event);
 
 void nvme_stop_ctrl(struct nvme_ctrl *ctrl)
 {
     nvme_mpath_stop(ctrl);
     nvme_auth_stop(ctrl);
     nvme_stop_keep_alive(ctrl);
     nvme_stop_failfast_work(ctrl);
     flush_work(&ctrl->async_event_work);
     cancel_work_sync(&ctrl->fw_act_work);
     if (ctrl->ops->stop_ctrl)
         ctrl->ops->stop_ctrl(ctrl);
 }
 EXPORT_SYMBOL_GPL(nvme_stop_ctrl);
 
 void nvme_start_ctrl(struct nvme_ctrl *ctrl)
 {
     nvme_start_keep_alive(ctrl);
 
     nvme_enable_aen(ctrl);
 
     if (ctrl->queue_count > 1) {
         nvme_queue_scan(ctrl);
         nvme_start_queues(ctrl);
         nvme_mpath_update(ctrl);
     }
 
     nvme_change_uevent(ctrl, "NVME_EVENT=connected");
 }
 EXPORT_SYMBOL_GPL(nvme_start_ctrl);
 
 void nvme_uninit_ctrl(struct nvme_ctrl *ctrl)
 {
     nvme_hwmon_exit(ctrl);
     nvme_fault_inject_fini(&ctrl->fault_inject);
     dev_pm_qos_hide_latency_tolerance(ctrl->device);
     cdev_device_del(&ctrl->cdev, ctrl->device);
     nvme_put_ctrl(ctrl);
 }
 EXPORT_SYMBOL_GPL(nvme_uninit_ctrl);
 
 static void nvme_free_cels(struct nvme_ctrl *ctrl)
 {
     struct nvme_effects_log *cel;
     unsigned long i;
 
     xa_for_each(&ctrl->cels, i, cel) {
         xa_erase(&ctrl->cels, i);
         kfree(cel);
     }
 
     xa_destroy(&ctrl->cels);
 }
 
 static void nvme_free_ctrl(struct device *dev)
 {
     struct nvme_ctrl *ctrl =
         container_of(dev, struct nvme_ctrl, ctrl_device);
     struct nvme_subsystem *subsys = ctrl->subsys;
 
     if (!subsys || ctrl->instance != subsys->instance)
         ida_free(&nvme_instance_ida, ctrl->instance);
 
     nvme_free_cels(ctrl);
     nvme_mpath_uninit(ctrl);
     nvme_auth_stop(ctrl);
     nvme_auth_free(ctrl);
     __free_page(ctrl->discard_page);
 
     if (subsys) {
         mutex_lock(&nvme_subsystems_lock);
         list_del(&ctrl->subsys_entry);
         sysfs_remove_link(&subsys->dev.kobj, dev_name(ctrl->device));
         mutex_unlock(&nvme_subsystems_lock);
     }
 
     ctrl->ops->free_ctrl(ctrl);
 
     if (subsys)
         nvme_put_subsystem(subsys);
 }
 
 /*
  * Initialize a NVMe controller structures.  This needs to be called during
  * earliest initialization so that we have the initialized structured around
  * during probing.
  */
 int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
         const struct nvme_ctrl_ops *ops, unsigned long quirks)
 {
     int ret;
 
     ctrl->state = NVME_CTRL_NEW;
     clear_bit(NVME_CTRL_FAILFAST_EXPIRED, &ctrl->flags);
     spin_lock_init(&ctrl->lock);
     mutex_init(&ctrl->scan_lock);
     INIT_LIST_HEAD(&ctrl->namespaces);
     xa_init(&ctrl->cels);
     init_rwsem(&ctrl->namespaces_rwsem);
     ctrl->dev = dev;
     ctrl->ops = ops;
     ctrl->quirks = quirks;
     ctrl->numa_node = NUMA_NO_NODE;
     INIT_WORK(&ctrl->scan_work, nvme_scan_work);
     INIT_WORK(&ctrl->async_event_work, nvme_async_event_work);
     INIT_WORK(&ctrl->fw_act_work, nvme_fw_act_work);
     INIT_WORK(&ctrl->delete_work, nvme_delete_ctrl_work);
     init_waitqueue_head(&ctrl->state_wq);
 
     INIT_DELAYED_WORK(&ctrl->ka_work, nvme_keep_alive_work);
     INIT_DELAYED_WORK(&ctrl->failfast_work, nvme_failfast_work);
     memset(&ctrl->ka_cmd, 0, sizeof(ctrl->ka_cmd));
     ctrl->ka_cmd.common.opcode = nvme_admin_keep_alive;
 
     BUILD_BUG_ON(NVME_DSM_MAX_RANGES * sizeof(struct nvme_dsm_range) >
             PAGE_SIZE);
     ctrl->discard_page = alloc_page(GFP_KERNEL);
     if (!ctrl->discard_page) {
         ret = -ENOMEM;
         goto out;
     }
 
     ret = ida_alloc(&nvme_instance_ida, GFP_KERNEL);
     if (ret < 0)
         goto out;
     ctrl->instance = ret;
 
     device_initialize(&ctrl->ctrl_device);
     ctrl->device = &ctrl->ctrl_device;
     ctrl->device->devt = MKDEV(MAJOR(nvme_ctrl_base_chr_devt),
             ctrl->instance);
     ctrl->device->class = nvme_class;
     ctrl->device->parent = ctrl->dev;
     ctrl->device->groups = nvme_dev_attr_groups;
     ctrl->device->release = nvme_free_ctrl;
     dev_set_drvdata(ctrl->device, ctrl);
     ret = dev_set_name(ctrl->device, "nvme%d", ctrl->instance);
     if (ret)
         goto out_release_instance;
 
     nvme_get_ctrl(ctrl);
     cdev_init(&ctrl->cdev, &nvme_dev_fops);
     ctrl->cdev.owner = ops->module;
     ret = cdev_device_add(&ctrl->cdev, ctrl->device);
     if (ret)
         goto out_free_name;
 
     /*
      * Initialize latency tolerance controls.  The sysfs files won't
      * be visible to userspace unless the device actually supports APST.
      */
     ctrl->device->power.set_latency_tolerance = nvme_set_latency_tolerance;
     dev_pm_qos_update_user_latency_tolerance(ctrl->device,
         min(default_ps_max_latency_us, (unsigned long)S32_MAX));
 
     nvme_fault_inject_init(&ctrl->fault_inject, dev_name(ctrl->device));
     nvme_mpath_init_ctrl(ctrl);
     nvme_auth_init_ctrl(ctrl);
 
     return 0;
 out_free_name:
     nvme_put_ctrl(ctrl);
     kfree_const(ctrl->device->kobj.name);
 out_release_instance:
     ida_free(&nvme_instance_ida, ctrl->instance);
 out:
     if (ctrl->discard_page)
         __free_page(ctrl->discard_page);
     return ret;
 }
 EXPORT_SYMBOL_GPL(nvme_init_ctrl);
 
 static void nvme_start_ns_queue(struct nvme_ns *ns)
 {
     if (test_and_clear_bit(NVME_NS_STOPPED, &ns->flags))
         blk_mq_unquiesce_queue(ns->queue);
 }
 
 static void nvme_stop_ns_queue(struct nvme_ns *ns)
 {
     if (!test_and_set_bit(NVME_NS_STOPPED, &ns->flags))
         blk_mq_quiesce_queue(ns->queue);
     else
         blk_mq_wait_quiesce_done(ns->queue);
 }
 
 /*
  * Prepare a queue for teardown.
  *
  * This must forcibly unquiesce queues to avoid blocking dispatch, and only set
  * the capacity to 0 after that to avoid blocking dispatchers that may be
  * holding bd_butex.  This will end buffered writers dirtying pages that can't
  * be synced.
  */
 static void nvme_set_queue_dying(struct nvme_ns *ns)
 {
     if (test_and_set_bit(NVME_NS_DEAD, &ns->flags))
         return;
 
     blk_mark_disk_dead(ns->disk);
     nvme_start_ns_queue(ns);
 
     set_capacity_and_notify(ns->disk, 0);
 }
 
 /**
  * nvme_kill_queues(): Ends all namespace queues
  * @ctrl: the dead controller that needs to end
  *
  * Call this function when the driver determines it is unable to get the
  * controller in a state capable of servicing IO.
  */
 void nvme_kill_queues(struct nvme_ctrl *ctrl)
 {
     struct nvme_ns *ns;
 
     down_read(&ctrl->namespaces_rwsem);
 
     /* Forcibly unquiesce queues to avoid blocking dispatch */
     if (ctrl->admin_q && !blk_queue_dying(ctrl->admin_q))
         nvme_start_admin_queue(ctrl);
 
     list_for_each_entry(ns, &ctrl->namespaces, list)
         nvme_set_queue_dying(ns);
 
     up_read(&ctrl->namespaces_rwsem);
 }
 EXPORT_SYMBOL_GPL(nvme_kill_queues);
 
 void nvme_unfreeze(struct nvme_ctrl *ctrl)
 {
     struct nvme_ns *ns;
 
     down_read(&ctrl->namespaces_rwsem);
     list_for_each_entry(ns, &ctrl->namespaces, list)
         blk_mq_unfreeze_queue(ns->queue);
     up_read(&ctrl->namespaces_rwsem);
 }
 EXPORT_SYMBOL_GPL(nvme_unfreeze);
 
 int nvme_wait_freeze_timeout(struct nvme_ctrl *ctrl, long timeout)
 {
     struct nvme_ns *ns;
 
     down_read(&ctrl->namespaces_rwsem);
     list_for_each_entry(ns, &ctrl->namespaces, list) {
         timeout = blk_mq_freeze_queue_wait_timeout(ns->queue, timeout);
         if (timeout <= 0)
             break;
     }
     up_read(&ctrl->namespaces_rwsem);
     return timeout;
 }
 EXPORT_SYMBOL_GPL(nvme_wait_freeze_timeout);
 
 void nvme_wait_freeze(struct nvme_ctrl *ctrl)
 {
     struct nvme_ns *ns;
 
     down_read(&ctrl->namespaces_rwsem);
     list_for_each_entry(ns, &ctrl->namespaces, list)
         blk_mq_freeze_queue_wait(ns->queue);
     up_read(&ctrl->namespaces_rwsem);
 }
 EXPORT_SYMBOL_GPL(nvme_wait_freeze);
 
 void nvme_start_freeze(struct nvme_ctrl *ctrl)
 {
     struct nvme_ns *ns;
 
     down_read(&ctrl->namespaces_rwsem);
     list_for_each_entry(ns, &ctrl->namespaces, list)
         blk_freeze_queue_start(ns->queue);
     up_read(&ctrl->namespaces_rwsem);
 }
 EXPORT_SYMBOL_GPL(nvme_start_freeze);
 
 void nvme_stop_queues(struct nvme_ctrl *ctrl)
 {
     struct nvme_ns *ns;
 
     down_read(&ctrl->namespaces_rwsem);
     list_for_each_entry(ns, &ctrl->namespaces, list)
         nvme_stop_ns_queue(ns);
     up_read(&ctrl->namespaces_rwsem);
 }
 EXPORT_SYMBOL_GPL(nvme_stop_queues);
 
 void nvme_start_queues(struct nvme_ctrl *ctrl)
 {
     struct nvme_ns *ns;
 
     down_read(&ctrl->namespaces_rwsem);
     list_for_each_entry(ns, &ctrl->namespaces, list)
         nvme_start_ns_queue(ns);
     up_read(&ctrl->namespaces_rwsem);
 }
 EXPORT_SYMBOL_GPL(nvme_start_queues);
 
 void nvme_stop_admin_queue(struct nvme_ctrl *ctrl)
 {
     if (!test_and_set_bit(NVME_CTRL_ADMIN_Q_STOPPED, &ctrl->flags))
         blk_mq_quiesce_queue(ctrl->admin_q);
     else
         blk_mq_wait_quiesce_done(ctrl->admin_q);
 }
 EXPORT_SYMBOL_GPL(nvme_stop_admin_queue);
 
 void nvme_start_admin_queue(struct nvme_ctrl *ctrl)
 {
     if (test_and_clear_bit(NVME_CTRL_ADMIN_Q_STOPPED, &ctrl->flags))
         blk_mq_unquiesce_queue(ctrl->admin_q);
 }
 EXPORT_SYMBOL_GPL(nvme_start_admin_queue);
 
 void nvme_sync_io_queues(struct nvme_ctrl *ctrl)
 {
     struct nvme_ns *ns;
 
     down_read(&ctrl->namespaces_rwsem);
     list_for_each_entry(ns, &ctrl->namespaces, list)
         blk_sync_queue(ns->queue);
     up_read(&ctrl->namespaces_rwsem);
 }
 EXPORT_SYMBOL_GPL(nvme_sync_io_queues);
 
 void nvme_sync_queues(struct nvme_ctrl *ctrl)
 {
     nvme_sync_io_queues(ctrl);
     if (ctrl->admin_q)
         blk_sync_queue(ctrl->admin_q);
 }
 EXPORT_SYMBOL_GPL(nvme_sync_queues);
 
 struct nvme_ctrl *nvme_ctrl_from_file(struct file *file)
 {
     if (file->f_op != &nvme_dev_fops)
         return NULL;
     return file->private_data;
 }
 EXPORT_SYMBOL_NS_GPL(nvme_ctrl_from_file, NVME_TARGET_PASSTHRU);
 
 /*
  * Check we didn't inadvertently grow the command structure sizes:
  */
 static inline void _nvme_check_size(void)
 {
     BUILD_BUG_ON(sizeof(struct nvme_common_command) != 64);
     BUILD_BUG_ON(sizeof(struct nvme_rw_command) != 64);
     BUILD_BUG_ON(sizeof(struct nvme_identify) != 64);
     BUILD_BUG_ON(sizeof(struct nvme_features) != 64);
     BUILD_BUG_ON(sizeof(struct nvme_download_firmware) != 64);
     BUILD_BUG_ON(sizeof(struct nvme_format_cmd) != 64);
     BUILD_BUG_ON(sizeof(struct nvme_dsm_cmd) != 64);
     BUILD_BUG_ON(sizeof(struct nvme_write_zeroes_cmd) != 64);
     BUILD_BUG_ON(sizeof(struct nvme_abort_cmd) != 64);
     BUILD_BUG_ON(sizeof(struct nvme_get_log_page_command) != 64);
     BUILD_BUG_ON(sizeof(struct nvme_command) != 64);
     BUILD_BUG_ON(sizeof(struct nvme_id_ctrl) != NVME_IDENTIFY_DATA_SIZE);
     BUILD_BUG_ON(sizeof(struct nvme_id_ns) != NVME_IDENTIFY_DATA_SIZE);
     BUILD_BUG_ON(sizeof(struct nvme_id_ns_cs_indep) !=
             NVME_IDENTIFY_DATA_SIZE);
     BUILD_BUG_ON(sizeof(struct nvme_id_ns_zns) != NVME_IDENTIFY_DATA_SIZE);
     BUILD_BUG_ON(sizeof(struct nvme_id_ns_nvm) != NVME_IDENTIFY_DATA_SIZE);
     BUILD_BUG_ON(sizeof(struct nvme_id_ctrl_zns) != NVME_IDENTIFY_DATA_SIZE);
     BUILD_BUG_ON(sizeof(struct nvme_id_ctrl_nvm) != NVME_IDENTIFY_DATA_SIZE);
     BUILD_BUG_ON(sizeof(struct nvme_lba_range_type) != 64);
     BUILD_BUG_ON(sizeof(struct nvme_smart_log) != 512);
     BUILD_BUG_ON(sizeof(struct nvme_dbbuf) != 64);
     BUILD_BUG_ON(sizeof(struct nvme_directive_cmd) != 64);
     BUILD_BUG_ON(sizeof(struct nvme_feat_host_behavior) != 512);
 }
 
 
 static int __init nvme_core_init(void)
 {
     int result = -ENOMEM;
 
     _nvme_check_size();
 
     nvme_wq = alloc_workqueue("nvme-wq",
             WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS, 0);
     if (!nvme_wq)
         goto out;
 
     nvme_reset_wq = alloc_workqueue("nvme-reset-wq",
             WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS, 0);
     if (!nvme_reset_wq)
         goto destroy_wq;
 
     nvme_delete_wq = alloc_workqueue("nvme-delete-wq",
             WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS, 0);
     if (!nvme_delete_wq)
         goto destroy_reset_wq;
 
     result = alloc_chrdev_region(&nvme_ctrl_base_chr_devt, 0,
             NVME_MINORS, "nvme");
     if (result < 0)
         goto destroy_delete_wq;
 
     nvme_class = class_create(THIS_MODULE, "nvme");
     if (IS_ERR(nvme_class)) {
         result = PTR_ERR(nvme_class);
         goto unregister_chrdev;
     }
     nvme_class->dev_uevent = nvme_class_uevent;
 
     nvme_subsys_class = class_create(THIS_MODULE, "nvme-subsystem");
     if (IS_ERR(nvme_subsys_class)) {
         result = PTR_ERR(nvme_subsys_class);
         goto destroy_class;
     }
 
     result = alloc_chrdev_region(&nvme_ns_chr_devt, 0, NVME_MINORS,
                      "nvme-generic");
     if (result < 0)
         goto destroy_subsys_class;
 
     nvme_ns_chr_class = class_create(THIS_MODULE, "nvme-generic");
     if (IS_ERR(nvme_ns_chr_class)) {
         result = PTR_ERR(nvme_ns_chr_class);
         goto unregister_generic_ns;
     }
 
     return 0;
 
 unregister_generic_ns:
     unregister_chrdev_region(nvme_ns_chr_devt, NVME_MINORS);
 destroy_subsys_class:
     class_destroy(nvme_subsys_class);
 destroy_class:
     class_destroy(nvme_class);
 unregister_chrdev:
     unregister_chrdev_region(nvme_ctrl_base_chr_devt, NVME_MINORS);
 destroy_delete_wq:
     destroy_workqueue(nvme_delete_wq);
 destroy_reset_wq:
     destroy_workqueue(nvme_reset_wq);
 destroy_wq:
     destroy_workqueue(nvme_wq);
 out:
     return result;
 }
 
 static void __exit nvme_core_exit(void)
 {
     class_destroy(nvme_ns_chr_class);
     class_destroy(nvme_subsys_class);
     class_destroy(nvme_class);
     unregister_chrdev_region(nvme_ns_chr_devt, NVME_MINORS);
     unregister_chrdev_region(nvme_ctrl_base_chr_devt, NVME_MINORS);
     destroy_workqueue(nvme_delete_wq);
     destroy_workqueue(nvme_reset_wq);
     destroy_workqueue(nvme_wq);
     ida_destroy(&nvme_ns_chr_minor_ida);
     ida_destroy(&nvme_instance_ida);
 }
 
 MODULE_LICENSE("GPL");
 MODULE_VERSION("1.0");
 module_init(nvme_core_init);
 module_exit(nvme_core_exit);