OSCL-LXR linux-6.0.1/​drivers/​infiniband/​ulp/​srpt/​ib_srpt.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

 /*
  * Copyright (c) 2006 - 2009 Mellanox Technology Inc.  All rights reserved.
  * Copyright (C) 2008 - 2011 Bart Van Assche <bvanassche@acm.org>.
  *
  * This software is available to you under a choice of one of two
  * licenses.  You may choose to be licensed under the terms of the GNU
  * General Public License (GPL) Version 2, available from the file
  * COPYING in the main directory of this source tree, or the
  * OpenIB.org BSD license below:
  *
  *     Redistribution and use in source and binary forms, with or
  *     without modification, are permitted provided that the following
  *     conditions are met:
  *
  *      - Redistributions of source code must retain the above
  *        copyright notice, this list of conditions and the following
  *        disclaimer.
  *
  *      - Redistributions in binary form must reproduce the above
  *        copyright notice, this list of conditions and the following
  *        disclaimer in the documentation and/or other materials
  *        provided with the distribution.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  *
  */
 
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/err.h>
 #include <linux/ctype.h>
 #include <linux/kthread.h>
 #include <linux/string.h>
 #include <linux/delay.h>
 #include <linux/atomic.h>
 #include <linux/inet.h>
 #include <rdma/ib_cache.h>
 #include <scsi/scsi_proto.h>
 #include <scsi/scsi_tcq.h>
 #include <target/target_core_base.h>
 #include <target/target_core_fabric.h>
 #include "ib_srpt.h"
 
 /* Name of this kernel module. */
 #define DRV_NAME        "ib_srpt"
 
 #define SRPT_ID_STRING  "Linux SRP target"
 
 #undef pr_fmt
 #define pr_fmt(fmt) DRV_NAME " " fmt
 
 MODULE_AUTHOR("Vu Pham and Bart Van Assche");
 MODULE_DESCRIPTION("SCSI RDMA Protocol target driver");
 MODULE_LICENSE("Dual BSD/GPL");
 
 /*
  * Global Variables
  */
 
 static u64 srpt_service_guid;
 static DEFINE_SPINLOCK(srpt_dev_lock);  /* Protects srpt_dev_list. */
 static LIST_HEAD(srpt_dev_list);    /* List of srpt_device structures. */
 
 static unsigned srp_max_req_size = DEFAULT_MAX_REQ_SIZE;
 module_param(srp_max_req_size, int, 0444);
 MODULE_PARM_DESC(srp_max_req_size,
          "Maximum size of SRP request messages in bytes.");
 
 static int srpt_srq_size = DEFAULT_SRPT_SRQ_SIZE;
 module_param(srpt_srq_size, int, 0444);
 MODULE_PARM_DESC(srpt_srq_size,
          "Shared receive queue (SRQ) size.");
 
 static int srpt_get_u64_x(char *buffer, const struct kernel_param *kp)
 {
     return sprintf(buffer, "0x%016llx\n", *(u64 *)kp->arg);
 }
 module_param_call(srpt_service_guid, NULL, srpt_get_u64_x, &srpt_service_guid,
           0444);
 MODULE_PARM_DESC(srpt_service_guid,
          "Using this value for ioc_guid, id_ext, and cm_listen_id instead of using the node_guid of the first HCA.");
 
 static struct ib_client srpt_client;
 /* Protects both rdma_cm_port and rdma_cm_id. */
 static DEFINE_MUTEX(rdma_cm_mutex);
 /* Port number RDMA/CM will bind to. */
 static u16 rdma_cm_port;
 static struct rdma_cm_id *rdma_cm_id;
 static void srpt_release_cmd(struct se_cmd *se_cmd);
 static void srpt_free_ch(struct kref *kref);
 static int srpt_queue_status(struct se_cmd *cmd);
 static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc);
 static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc);
 static void srpt_process_wait_list(struct srpt_rdma_ch *ch);
 
 /*
  * The only allowed channel state changes are those that change the channel
  * state into a state with a higher numerical value. Hence the new > prev test.
  */
 static bool srpt_set_ch_state(struct srpt_rdma_ch *ch, enum rdma_ch_state new)
 {
     unsigned long flags;
     enum rdma_ch_state prev;
     bool changed = false;
 
     spin_lock_irqsave(&ch->spinlock, flags);
     prev = ch->state;
     if (new > prev) {
         ch->state = new;
         changed = true;
     }
     spin_unlock_irqrestore(&ch->spinlock, flags);
 
     return changed;
 }
 
 /**
  * srpt_event_handler - asynchronous IB event callback function
  * @handler: IB event handler registered by ib_register_event_handler().
  * @event: Description of the event that occurred.
  *
  * Callback function called by the InfiniBand core when an asynchronous IB
  * event occurs. This callback may occur in interrupt context. See also
  * section 11.5.2, Set Asynchronous Event Handler in the InfiniBand
  * Architecture Specification.
  */
 static void srpt_event_handler(struct ib_event_handler *handler,
                    struct ib_event *event)
 {
     struct srpt_device *sdev =
         container_of(handler, struct srpt_device, event_handler);
     struct srpt_port *sport;
     u8 port_num;
 
     pr_debug("ASYNC event= %d on device= %s\n", event->event,
          dev_name(&sdev->device->dev));
 
     switch (event->event) {
     case IB_EVENT_PORT_ERR:
         port_num = event->element.port_num - 1;
         if (port_num < sdev->device->phys_port_cnt) {
             sport = &sdev->port[port_num];
             sport->lid = 0;
             sport->sm_lid = 0;
         } else {
             WARN(true, "event %d: port_num %d out of range 1..%d\n",
                  event->event, port_num + 1,
                  sdev->device->phys_port_cnt);
         }
         break;
     case IB_EVENT_PORT_ACTIVE:
     case IB_EVENT_LID_CHANGE:
     case IB_EVENT_PKEY_CHANGE:
     case IB_EVENT_SM_CHANGE:
     case IB_EVENT_CLIENT_REREGISTER:
     case IB_EVENT_GID_CHANGE:
         /* Refresh port data asynchronously. */
         port_num = event->element.port_num - 1;
         if (port_num < sdev->device->phys_port_cnt) {
             sport = &sdev->port[port_num];
             if (!sport->lid && !sport->sm_lid)
                 schedule_work(&sport->work);
         } else {
             WARN(true, "event %d: port_num %d out of range 1..%d\n",
                  event->event, port_num + 1,
                  sdev->device->phys_port_cnt);
         }
         break;
     default:
         pr_err("received unrecognized IB event %d\n", event->event);
         break;
     }
 }
 
 /**
  * srpt_srq_event - SRQ event callback function
  * @event: Description of the event that occurred.
  * @ctx: Context pointer specified at SRQ creation time.
  */
 static void srpt_srq_event(struct ib_event *event, void *ctx)
 {
     pr_debug("SRQ event %d\n", event->event);
 }
 
 static const char *get_ch_state_name(enum rdma_ch_state s)
 {
     switch (s) {
     case CH_CONNECTING:
         return "connecting";
     case CH_LIVE:
         return "live";
     case CH_DISCONNECTING:
         return "disconnecting";
     case CH_DRAINING:
         return "draining";
     case CH_DISCONNECTED:
         return "disconnected";
     }
     return "???";
 }
 
 /**
  * srpt_qp_event - QP event callback function
  * @event: Description of the event that occurred.
  * @ch: SRPT RDMA channel.
  */
 static void srpt_qp_event(struct ib_event *event, struct srpt_rdma_ch *ch)
 {
     pr_debug("QP event %d on ch=%p sess_name=%s-%d state=%s\n",
          event->event, ch, ch->sess_name, ch->qp->qp_num,
          get_ch_state_name(ch->state));
 
     switch (event->event) {
     case IB_EVENT_COMM_EST:
         if (ch->using_rdma_cm)
             rdma_notify(ch->rdma_cm.cm_id, event->event);
         else
             ib_cm_notify(ch->ib_cm.cm_id, event->event);
         break;
     case IB_EVENT_QP_LAST_WQE_REACHED:
         pr_debug("%s-%d, state %s: received Last WQE event.\n",
              ch->sess_name, ch->qp->qp_num,
              get_ch_state_name(ch->state));
         break;
     default:
         pr_err("received unrecognized IB QP event %d\n", event->event);
         break;
     }
 }
 
 /**
  * srpt_set_ioc - initialize a IOUnitInfo structure
  * @c_list: controller list.
  * @slot: one-based slot number.
  * @value: four-bit value.
  *
  * Copies the lowest four bits of value in element slot of the array of four
  * bit elements called c_list (controller list). The index slot is one-based.
  */
 static void srpt_set_ioc(u8 *c_list, u32 slot, u8 value)
 {
     u16 id;
     u8 tmp;
 
     id = (slot - 1) / 2;
     if (slot & 0x1) {
         tmp = c_list[id] & 0xf;
         c_list[id] = (value << 4) | tmp;
     } else {
         tmp = c_list[id] & 0xf0;
         c_list[id] = (value & 0xf) | tmp;
     }
 }
 
 /**
  * srpt_get_class_port_info - copy ClassPortInfo to a management datagram
  * @mad: Datagram that will be sent as response to DM_ATTR_CLASS_PORT_INFO.
  *
  * See also section 16.3.3.1 ClassPortInfo in the InfiniBand Architecture
  * Specification.
  */
 static void srpt_get_class_port_info(struct ib_dm_mad *mad)
 {
     struct ib_class_port_info *cif;
 
     cif = (struct ib_class_port_info *)mad->data;
     memset(cif, 0, sizeof(*cif));
     cif->base_version = 1;
     cif->class_version = 1;
 
     ib_set_cpi_resp_time(cif, 20);
     mad->mad_hdr.status = 0;
 }
 
 /**
  * srpt_get_iou - write IOUnitInfo to a management datagram
  * @mad: Datagram that will be sent as response to DM_ATTR_IOU_INFO.
  *
  * See also section 16.3.3.3 IOUnitInfo in the InfiniBand Architecture
  * Specification. See also section B.7, table B.6 in the SRP r16a document.
  */
 static void srpt_get_iou(struct ib_dm_mad *mad)
 {
     struct ib_dm_iou_info *ioui;
     u8 slot;
     int i;
 
     ioui = (struct ib_dm_iou_info *)mad->data;
     ioui->change_id = cpu_to_be16(1);
     ioui->max_controllers = 16;
 
     /* set present for slot 1 and empty for the rest */
     srpt_set_ioc(ioui->controller_list, 1, 1);
     for (i = 1, slot = 2; i < 16; i++, slot++)
         srpt_set_ioc(ioui->controller_list, slot, 0);
 
     mad->mad_hdr.status = 0;
 }
 
 /**
  * srpt_get_ioc - write IOControllerprofile to a management datagram
  * @sport: HCA port through which the MAD has been received.
  * @slot: Slot number specified in DM_ATTR_IOC_PROFILE query.
  * @mad: Datagram that will be sent as response to DM_ATTR_IOC_PROFILE.
  *
  * See also section 16.3.3.4 IOControllerProfile in the InfiniBand
  * Architecture Specification. See also section B.7, table B.7 in the SRP
  * r16a document.
  */
 static void srpt_get_ioc(struct srpt_port *sport, u32 slot,
              struct ib_dm_mad *mad)
 {
     struct srpt_device *sdev = sport->sdev;
     struct ib_dm_ioc_profile *iocp;
     int send_queue_depth;
 
     iocp = (struct ib_dm_ioc_profile *)mad->data;
 
     if (!slot || slot > 16) {
         mad->mad_hdr.status
             = cpu_to_be16(DM_MAD_STATUS_INVALID_FIELD);
         return;
     }
 
     if (slot > 2) {
         mad->mad_hdr.status
             = cpu_to_be16(DM_MAD_STATUS_NO_IOC);
         return;
     }
 
     if (sdev->use_srq)
         send_queue_depth = sdev->srq_size;
     else
         send_queue_depth = min(MAX_SRPT_RQ_SIZE,
                        sdev->device->attrs.max_qp_wr);
 
     memset(iocp, 0, sizeof(*iocp));
     strcpy(iocp->id_string, SRPT_ID_STRING);
     iocp->guid = cpu_to_be64(srpt_service_guid);
     iocp->vendor_id = cpu_to_be32(sdev->device->attrs.vendor_id);
     iocp->device_id = cpu_to_be32(sdev->device->attrs.vendor_part_id);
     iocp->device_version = cpu_to_be16(sdev->device->attrs.hw_ver);
     iocp->subsys_vendor_id = cpu_to_be32(sdev->device->attrs.vendor_id);
     iocp->subsys_device_id = 0x0;
     iocp->io_class = cpu_to_be16(SRP_REV16A_IB_IO_CLASS);
     iocp->io_subclass = cpu_to_be16(SRP_IO_SUBCLASS);
     iocp->protocol = cpu_to_be16(SRP_PROTOCOL);
     iocp->protocol_version = cpu_to_be16(SRP_PROTOCOL_VERSION);
     iocp->send_queue_depth = cpu_to_be16(send_queue_depth);
     iocp->rdma_read_depth = 4;
     iocp->send_size = cpu_to_be32(srp_max_req_size);
     iocp->rdma_size = cpu_to_be32(min(sport->port_attrib.srp_max_rdma_size,
                       1U << 24));
     iocp->num_svc_entries = 1;
     iocp->op_cap_mask = SRP_SEND_TO_IOC | SRP_SEND_FROM_IOC |
         SRP_RDMA_READ_FROM_IOC | SRP_RDMA_WRITE_FROM_IOC;
 
     mad->mad_hdr.status = 0;
 }
 
 /**
  * srpt_get_svc_entries - write ServiceEntries to a management datagram
  * @ioc_guid: I/O controller GUID to use in reply.
  * @slot: I/O controller number.
  * @hi: End of the range of service entries to be specified in the reply.
  * @lo: Start of the range of service entries to be specified in the reply..
  * @mad: Datagram that will be sent as response to DM_ATTR_SVC_ENTRIES.
  *
  * See also section 16.3.3.5 ServiceEntries in the InfiniBand Architecture
  * Specification. See also section B.7, table B.8 in the SRP r16a document.
  */
 static void srpt_get_svc_entries(u64 ioc_guid,
                  u16 slot, u8 hi, u8 lo, struct ib_dm_mad *mad)
 {
     struct ib_dm_svc_entries *svc_entries;
 
     WARN_ON(!ioc_guid);
 
     if (!slot || slot > 16) {
         mad->mad_hdr.status
             = cpu_to_be16(DM_MAD_STATUS_INVALID_FIELD);
         return;
     }
 
     if (slot > 2 || lo > hi || hi > 1) {
         mad->mad_hdr.status
             = cpu_to_be16(DM_MAD_STATUS_NO_IOC);
         return;
     }
 
     svc_entries = (struct ib_dm_svc_entries *)mad->data;
     memset(svc_entries, 0, sizeof(*svc_entries));
     svc_entries->service_entries[0].id = cpu_to_be64(ioc_guid);
     snprintf(svc_entries->service_entries[0].name,
          sizeof(svc_entries->service_entries[0].name),
          "%s%016llx",
          SRP_SERVICE_NAME_PREFIX,
          ioc_guid);
 
     mad->mad_hdr.status = 0;
 }
 
 /**
  * srpt_mgmt_method_get - process a received management datagram
  * @sp:      HCA port through which the MAD has been received.
  * @rq_mad:  received MAD.
  * @rsp_mad: response MAD.
  */
 static void srpt_mgmt_method_get(struct srpt_port *sp, struct ib_mad *rq_mad,
                  struct ib_dm_mad *rsp_mad)
 {
     u16 attr_id;
     u32 slot;
     u8 hi, lo;
 
     attr_id = be16_to_cpu(rq_mad->mad_hdr.attr_id);
     switch (attr_id) {
     case DM_ATTR_CLASS_PORT_INFO:
         srpt_get_class_port_info(rsp_mad);
         break;
     case DM_ATTR_IOU_INFO:
         srpt_get_iou(rsp_mad);
         break;
     case DM_ATTR_IOC_PROFILE:
         slot = be32_to_cpu(rq_mad->mad_hdr.attr_mod);
         srpt_get_ioc(sp, slot, rsp_mad);
         break;
     case DM_ATTR_SVC_ENTRIES:
         slot = be32_to_cpu(rq_mad->mad_hdr.attr_mod);
         hi = (u8) ((slot >> 8) & 0xff);
         lo = (u8) (slot & 0xff);
         slot = (u16) ((slot >> 16) & 0xffff);
         srpt_get_svc_entries(srpt_service_guid,
                      slot, hi, lo, rsp_mad);
         break;
     default:
         rsp_mad->mad_hdr.status =
             cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
         break;
     }
 }
 
 /**
  * srpt_mad_send_handler - MAD send completion callback
  * @mad_agent: Return value of ib_register_mad_agent().
  * @mad_wc: Work completion reporting that the MAD has been sent.
  */
 static void srpt_mad_send_handler(struct ib_mad_agent *mad_agent,
                   struct ib_mad_send_wc *mad_wc)
 {
     rdma_destroy_ah(mad_wc->send_buf->ah, RDMA_DESTROY_AH_SLEEPABLE);
     ib_free_send_mad(mad_wc->send_buf);
 }
 
 /**
  * srpt_mad_recv_handler - MAD reception callback function
  * @mad_agent: Return value of ib_register_mad_agent().
  * @send_buf: Not used.
  * @mad_wc: Work completion reporting that a MAD has been received.
  */
 static void srpt_mad_recv_handler(struct ib_mad_agent *mad_agent,
                   struct ib_mad_send_buf *send_buf,
                   struct ib_mad_recv_wc *mad_wc)
 {
     struct srpt_port *sport = (struct srpt_port *)mad_agent->context;
     struct ib_ah *ah;
     struct ib_mad_send_buf *rsp;
     struct ib_dm_mad *dm_mad;
 
     if (!mad_wc || !mad_wc->recv_buf.mad)
         return;
 
     ah = ib_create_ah_from_wc(mad_agent->qp->pd, mad_wc->wc,
                   mad_wc->recv_buf.grh, mad_agent->port_num);
     if (IS_ERR(ah))
         goto err;
 
     BUILD_BUG_ON(offsetof(struct ib_dm_mad, data) != IB_MGMT_DEVICE_HDR);
 
     rsp = ib_create_send_mad(mad_agent, mad_wc->wc->src_qp,
                  mad_wc->wc->pkey_index, 0,
                  IB_MGMT_DEVICE_HDR, IB_MGMT_DEVICE_DATA,
                  GFP_KERNEL,
                  IB_MGMT_BASE_VERSION);
     if (IS_ERR(rsp))
         goto err_rsp;
 
     rsp->ah = ah;
 
     dm_mad = rsp->mad;
     memcpy(dm_mad, mad_wc->recv_buf.mad, sizeof(*dm_mad));
     dm_mad->mad_hdr.method = IB_MGMT_METHOD_GET_RESP;
     dm_mad->mad_hdr.status = 0;
 
     switch (mad_wc->recv_buf.mad->mad_hdr.method) {
     case IB_MGMT_METHOD_GET:
         srpt_mgmt_method_get(sport, mad_wc->recv_buf.mad, dm_mad);
         break;
     case IB_MGMT_METHOD_SET:
         dm_mad->mad_hdr.status =
             cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
         break;
     default:
         dm_mad->mad_hdr.status =
             cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD);
         break;
     }
 
     if (!ib_post_send_mad(rsp, NULL)) {
         ib_free_recv_mad(mad_wc);
         /* will destroy_ah & free_send_mad in send completion */
         return;
     }
 
     ib_free_send_mad(rsp);
 
 err_rsp:
     rdma_destroy_ah(ah, RDMA_DESTROY_AH_SLEEPABLE);
 err:
     ib_free_recv_mad(mad_wc);
 }
 
 static int srpt_format_guid(char *buf, unsigned int size, const __be64 *guid)
 {
     const __be16 *g = (const __be16 *)guid;
 
     return snprintf(buf, size, "%04x:%04x:%04x:%04x",
             be16_to_cpu(g[0]), be16_to_cpu(g[1]),
             be16_to_cpu(g[2]), be16_to_cpu(g[3]));
 }
 
 /**
  * srpt_refresh_port - configure a HCA port
  * @sport: SRPT HCA port.
  *
  * Enable InfiniBand management datagram processing, update the cached sm_lid,
  * lid and gid values, and register a callback function for processing MADs
  * on the specified port.
  *
  * Note: It is safe to call this function more than once for the same port.
  */
 static int srpt_refresh_port(struct srpt_port *sport)
 {
     struct ib_mad_reg_req reg_req;
     struct ib_port_modify port_modify;
     struct ib_port_attr port_attr;
     int ret;
 
     ret = ib_query_port(sport->sdev->device, sport->port, &port_attr);
     if (ret)
         return ret;
 
     sport->sm_lid = port_attr.sm_lid;
     sport->lid = port_attr.lid;
 
     ret = rdma_query_gid(sport->sdev->device, sport->port, 0, &sport->gid);
     if (ret)
         return ret;
 
     srpt_format_guid(sport->guid_name, ARRAY_SIZE(sport->guid_name),
              &sport->gid.global.interface_id);
     snprintf(sport->gid_name, ARRAY_SIZE(sport->gid_name),
          "0x%016llx%016llx",
          be64_to_cpu(sport->gid.global.subnet_prefix),
          be64_to_cpu(sport->gid.global.interface_id));
 
     if (rdma_protocol_iwarp(sport->sdev->device, sport->port))
         return 0;
 
     memset(&port_modify, 0, sizeof(port_modify));
     port_modify.set_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP;
     port_modify.clr_port_cap_mask = 0;
 
     ret = ib_modify_port(sport->sdev->device, sport->port, 0, &port_modify);
     if (ret) {
         pr_warn("%s-%d: enabling device management failed (%d). Note: this is expected if SR-IOV is enabled.\n",
             dev_name(&sport->sdev->device->dev), sport->port, ret);
         return 0;
     }
 
     if (!sport->mad_agent) {
         memset(&reg_req, 0, sizeof(reg_req));
         reg_req.mgmt_class = IB_MGMT_CLASS_DEVICE_MGMT;
         reg_req.mgmt_class_version = IB_MGMT_BASE_VERSION;
         set_bit(IB_MGMT_METHOD_GET, reg_req.method_mask);
         set_bit(IB_MGMT_METHOD_SET, reg_req.method_mask);
 
         sport->mad_agent = ib_register_mad_agent(sport->sdev->device,
                              sport->port,
                              IB_QPT_GSI,
                              &reg_req, 0,
                              srpt_mad_send_handler,
                              srpt_mad_recv_handler,
                              sport, 0);
         if (IS_ERR(sport->mad_agent)) {
             pr_err("%s-%d: MAD agent registration failed (%ld). Note: this is expected if SR-IOV is enabled.\n",
                    dev_name(&sport->sdev->device->dev), sport->port,
                    PTR_ERR(sport->mad_agent));
             sport->mad_agent = NULL;
             memset(&port_modify, 0, sizeof(port_modify));
             port_modify.clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP;
             ib_modify_port(sport->sdev->device, sport->port, 0,
                        &port_modify);
 
         }
     }
 
     return 0;
 }
 
 /**
  * srpt_unregister_mad_agent - unregister MAD callback functions
  * @sdev: SRPT HCA pointer.
  * @port_cnt: number of ports with registered MAD
  *
  * Note: It is safe to call this function more than once for the same device.
  */
 static void srpt_unregister_mad_agent(struct srpt_device *sdev, int port_cnt)
 {
     struct ib_port_modify port_modify = {
         .clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP,
     };
     struct srpt_port *sport;
     int i;
 
     for (i = 1; i <= port_cnt; i++) {
         sport = &sdev->port[i - 1];
         WARN_ON(sport->port != i);
         if (sport->mad_agent) {
             ib_modify_port(sdev->device, i, 0, &port_modify);
             ib_unregister_mad_agent(sport->mad_agent);
             sport->mad_agent = NULL;
         }
     }
 }
 
 /**
  * srpt_alloc_ioctx - allocate a SRPT I/O context structure
  * @sdev: SRPT HCA pointer.
  * @ioctx_size: I/O context size.
  * @buf_cache: I/O buffer cache.
  * @dir: DMA data direction.
  */
 static struct srpt_ioctx *srpt_alloc_ioctx(struct srpt_device *sdev,
                        int ioctx_size,
                        struct kmem_cache *buf_cache,
                        enum dma_data_direction dir)
 {
     struct srpt_ioctx *ioctx;
 
     ioctx = kzalloc(ioctx_size, GFP_KERNEL);
     if (!ioctx)
         goto err;
 
     ioctx->buf = kmem_cache_alloc(buf_cache, GFP_KERNEL);
     if (!ioctx->buf)
         goto err_free_ioctx;
 
     ioctx->dma = ib_dma_map_single(sdev->device, ioctx->buf,
                        kmem_cache_size(buf_cache), dir);
     if (ib_dma_mapping_error(sdev->device, ioctx->dma))
         goto err_free_buf;
 
     return ioctx;
 
 err_free_buf:
     kmem_cache_free(buf_cache, ioctx->buf);
 err_free_ioctx:
     kfree(ioctx);
 err:
     return NULL;
 }
 
 /**
  * srpt_free_ioctx - free a SRPT I/O context structure
  * @sdev: SRPT HCA pointer.
  * @ioctx: I/O context pointer.
  * @buf_cache: I/O buffer cache.
  * @dir: DMA data direction.
  */
 static void srpt_free_ioctx(struct srpt_device *sdev, struct srpt_ioctx *ioctx,
                 struct kmem_cache *buf_cache,
                 enum dma_data_direction dir)
 {
     if (!ioctx)
         return;
 
     ib_dma_unmap_single(sdev->device, ioctx->dma,
                 kmem_cache_size(buf_cache), dir);
     kmem_cache_free(buf_cache, ioctx->buf);
     kfree(ioctx);
 }
 
 /**
  * srpt_alloc_ioctx_ring - allocate a ring of SRPT I/O context structures
  * @sdev:       Device to allocate the I/O context ring for.
  * @ring_size:  Number of elements in the I/O context ring.
  * @ioctx_size: I/O context size.
  * @buf_cache:  I/O buffer cache.
  * @alignment_offset: Offset in each ring buffer at which the SRP information
  *      unit starts.
  * @dir:        DMA data direction.
  */
 static struct srpt_ioctx **srpt_alloc_ioctx_ring(struct srpt_device *sdev,
                 int ring_size, int ioctx_size,
                 struct kmem_cache *buf_cache,
                 int alignment_offset,
                 enum dma_data_direction dir)
 {
     struct srpt_ioctx **ring;
     int i;
 
     WARN_ON(ioctx_size != sizeof(struct srpt_recv_ioctx) &&
         ioctx_size != sizeof(struct srpt_send_ioctx));
 
     ring = kvmalloc_array(ring_size, sizeof(ring[0]), GFP_KERNEL);
     if (!ring)
         goto out;
     for (i = 0; i < ring_size; ++i) {
         ring[i] = srpt_alloc_ioctx(sdev, ioctx_size, buf_cache, dir);
         if (!ring[i])
             goto err;
         ring[i]->index = i;
         ring[i]->offset = alignment_offset;
     }
     goto out;
 
 err:
     while (--i >= 0)
         srpt_free_ioctx(sdev, ring[i], buf_cache, dir);
     kvfree(ring);
     ring = NULL;
 out:
     return ring;
 }
 
 /**
  * srpt_free_ioctx_ring - free the ring of SRPT I/O context structures
  * @ioctx_ring: I/O context ring to be freed.
  * @sdev: SRPT HCA pointer.
  * @ring_size: Number of ring elements.
  * @buf_cache: I/O buffer cache.
  * @dir: DMA data direction.
  */
 static void srpt_free_ioctx_ring(struct srpt_ioctx **ioctx_ring,
                  struct srpt_device *sdev, int ring_size,
                  struct kmem_cache *buf_cache,
                  enum dma_data_direction dir)
 {
     int i;
 
     if (!ioctx_ring)
         return;
 
     for (i = 0; i < ring_size; ++i)
         srpt_free_ioctx(sdev, ioctx_ring[i], buf_cache, dir);
     kvfree(ioctx_ring);
 }
 
 /**
  * srpt_set_cmd_state - set the state of a SCSI command
  * @ioctx: Send I/O context.
  * @new: New I/O context state.
  *
  * Does not modify the state of aborted commands. Returns the previous command
  * state.
  */
 static enum srpt_command_state srpt_set_cmd_state(struct srpt_send_ioctx *ioctx,
                           enum srpt_command_state new)
 {
     enum srpt_command_state previous;
 
     previous = ioctx->state;
     if (previous != SRPT_STATE_DONE)
         ioctx->state = new;
 
     return previous;
 }
 
 /**
  * srpt_test_and_set_cmd_state - test and set the state of a command
  * @ioctx: Send I/O context.
  * @old: Current I/O context state.
  * @new: New I/O context state.
  *
  * Returns true if and only if the previous command state was equal to 'old'.
  */
 static bool srpt_test_and_set_cmd_state(struct srpt_send_ioctx *ioctx,
                     enum srpt_command_state old,
                     enum srpt_command_state new)
 {
     enum srpt_command_state previous;
 
     WARN_ON(!ioctx);
     WARN_ON(old == SRPT_STATE_DONE);
     WARN_ON(new == SRPT_STATE_NEW);
 
     previous = ioctx->state;
     if (previous == old)
         ioctx->state = new;
 
     return previous == old;
 }
 
 /**
  * srpt_post_recv - post an IB receive request
  * @sdev: SRPT HCA pointer.
  * @ch: SRPT RDMA channel.
  * @ioctx: Receive I/O context pointer.
  */
 static int srpt_post_recv(struct srpt_device *sdev, struct srpt_rdma_ch *ch,
               struct srpt_recv_ioctx *ioctx)
 {
     struct ib_sge list;
     struct ib_recv_wr wr;
 
     BUG_ON(!sdev);
     list.addr = ioctx->ioctx.dma + ioctx->ioctx.offset;
     list.length = srp_max_req_size;
     list.lkey = sdev->lkey;
 
     ioctx->ioctx.cqe.done = srpt_recv_done;
     wr.wr_cqe = &ioctx->ioctx.cqe;
     wr.next = NULL;
     wr.sg_list = &list;
     wr.num_sge = 1;
 
     if (sdev->use_srq)
         return ib_post_srq_recv(sdev->srq, &wr, NULL);
     else
         return ib_post_recv(ch->qp, &wr, NULL);
 }
 
 /**
  * srpt_zerolength_write - perform a zero-length RDMA write
  * @ch: SRPT RDMA channel.
  *
  * A quote from the InfiniBand specification: C9-88: For an HCA responder
  * using Reliable Connection service, for each zero-length RDMA READ or WRITE
  * request, the R_Key shall not be validated, even if the request includes
  * Immediate data.
  */
 static int srpt_zerolength_write(struct srpt_rdma_ch *ch)
 {
     struct ib_rdma_wr wr = {
         .wr = {
             .next       = NULL,
             { .wr_cqe   = &ch->zw_cqe, },
             .opcode     = IB_WR_RDMA_WRITE,
             .send_flags = IB_SEND_SIGNALED,
         }
     };
 
     pr_debug("%s-%d: queued zerolength write\n", ch->sess_name,
          ch->qp->qp_num);
 
     return ib_post_send(ch->qp, &wr.wr, NULL);
 }
 
 static void srpt_zerolength_write_done(struct ib_cq *cq, struct ib_wc *wc)
 {
     struct srpt_rdma_ch *ch = wc->qp->qp_context;
 
     pr_debug("%s-%d wc->status %d\n", ch->sess_name, ch->qp->qp_num,
          wc->status);
 
     if (wc->status == IB_WC_SUCCESS) {
         srpt_process_wait_list(ch);
     } else {
         if (srpt_set_ch_state(ch, CH_DISCONNECTED))
             schedule_work(&ch->release_work);
         else
             pr_debug("%s-%d: already disconnected.\n",
                  ch->sess_name, ch->qp->qp_num);
     }
 }
 
 static int srpt_alloc_rw_ctxs(struct srpt_send_ioctx *ioctx,
         struct srp_direct_buf *db, int nbufs, struct scatterlist **sg,
         unsigned *sg_cnt)
 {
     enum dma_data_direction dir = target_reverse_dma_direction(&ioctx->cmd);
     struct srpt_rdma_ch *ch = ioctx->ch;
     struct scatterlist *prev = NULL;
     unsigned prev_nents;
     int ret, i;
 
     if (nbufs == 1) {
         ioctx->rw_ctxs = &ioctx->s_rw_ctx;
     } else {
         ioctx->rw_ctxs = kmalloc_array(nbufs, sizeof(*ioctx->rw_ctxs),
             GFP_KERNEL);
         if (!ioctx->rw_ctxs)
             return -ENOMEM;
     }
 
     for (i = ioctx->n_rw_ctx; i < nbufs; i++, db++) {
         struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
         u64 remote_addr = be64_to_cpu(db->va);
         u32 size = be32_to_cpu(db->len);
         u32 rkey = be32_to_cpu(db->key);
 
         ret = target_alloc_sgl(&ctx->sg, &ctx->nents, size, false,
                 i < nbufs - 1);
         if (ret)
             goto unwind;
 
         ret = rdma_rw_ctx_init(&ctx->rw, ch->qp, ch->sport->port,
                 ctx->sg, ctx->nents, 0, remote_addr, rkey, dir);
         if (ret < 0) {
             target_free_sgl(ctx->sg, ctx->nents);
             goto unwind;
         }
 
         ioctx->n_rdma += ret;
         ioctx->n_rw_ctx++;
 
         if (prev) {
             sg_unmark_end(&prev[prev_nents - 1]);
             sg_chain(prev, prev_nents + 1, ctx->sg);
         } else {
             *sg = ctx->sg;
         }
 
         prev = ctx->sg;
         prev_nents = ctx->nents;
 
         *sg_cnt += ctx->nents;
     }
 
     return 0;
 
 unwind:
     while (--i >= 0) {
         struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
 
         rdma_rw_ctx_destroy(&ctx->rw, ch->qp, ch->sport->port,
                 ctx->sg, ctx->nents, dir);
         target_free_sgl(ctx->sg, ctx->nents);
     }
     if (ioctx->rw_ctxs != &ioctx->s_rw_ctx)
         kfree(ioctx->rw_ctxs);
     return ret;
 }
 
 static void srpt_free_rw_ctxs(struct srpt_rdma_ch *ch,
                     struct srpt_send_ioctx *ioctx)
 {
     enum dma_data_direction dir = target_reverse_dma_direction(&ioctx->cmd);
     int i;
 
     for (i = 0; i < ioctx->n_rw_ctx; i++) {
         struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
 
         rdma_rw_ctx_destroy(&ctx->rw, ch->qp, ch->sport->port,
                 ctx->sg, ctx->nents, dir);
         target_free_sgl(ctx->sg, ctx->nents);
     }
 
     if (ioctx->rw_ctxs != &ioctx->s_rw_ctx)
         kfree(ioctx->rw_ctxs);
 }
 
 static inline void *srpt_get_desc_buf(struct srp_cmd *srp_cmd)
 {
     /*
      * The pointer computations below will only be compiled correctly
      * if srp_cmd::add_data is declared as s8*, u8*, s8[] or u8[], so check
      * whether srp_cmd::add_data has been declared as a byte pointer.
      */
     BUILD_BUG_ON(!__same_type(srp_cmd->add_data[0], (s8)0) &&
              !__same_type(srp_cmd->add_data[0], (u8)0));
 
     /*
      * According to the SRP spec, the lower two bits of the 'ADDITIONAL
      * CDB LENGTH' field are reserved and the size in bytes of this field
      * is four times the value specified in bits 3..7. Hence the "& ~3".
      */
     return srp_cmd->add_data + (srp_cmd->add_cdb_len & ~3);
 }
 
 /**
  * srpt_get_desc_tbl - parse the data descriptors of a SRP_CMD request
  * @recv_ioctx: I/O context associated with the received command @srp_cmd.
  * @ioctx: I/O context that will be used for responding to the initiator.
  * @srp_cmd: Pointer to the SRP_CMD request data.
  * @dir: Pointer to the variable to which the transfer direction will be
  *   written.
  * @sg: [out] scatterlist for the parsed SRP_CMD.
  * @sg_cnt: [out] length of @sg.
  * @data_len: Pointer to the variable to which the total data length of all
  *   descriptors in the SRP_CMD request will be written.
  * @imm_data_offset: [in] Offset in SRP_CMD requests at which immediate data
  *   starts.
  *
  * This function initializes ioctx->nrbuf and ioctx->r_bufs.
  *
  * Returns -EINVAL when the SRP_CMD request contains inconsistent descriptors;
  * -ENOMEM when memory allocation fails and zero upon success.
  */
 static int srpt_get_desc_tbl(struct srpt_recv_ioctx *recv_ioctx,
         struct srpt_send_ioctx *ioctx,
         struct srp_cmd *srp_cmd, enum dma_data_direction *dir,
         struct scatterlist **sg, unsigned int *sg_cnt, u64 *data_len,
         u16 imm_data_offset)
 {
     BUG_ON(!dir);
     BUG_ON(!data_len);
 
     /*
      * The lower four bits of the buffer format field contain the DATA-IN
      * buffer descriptor format, and the highest four bits contain the
      * DATA-OUT buffer descriptor format.
      */
     if (srp_cmd->buf_fmt & 0xf)
         /* DATA-IN: transfer data from target to initiator (read). */
         *dir = DMA_FROM_DEVICE;
     else if (srp_cmd->buf_fmt >> 4)
         /* DATA-OUT: transfer data from initiator to target (write). */
         *dir = DMA_TO_DEVICE;
     else
         *dir = DMA_NONE;
 
     /* initialize data_direction early as srpt_alloc_rw_ctxs needs it */
     ioctx->cmd.data_direction = *dir;
 
     if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_DIRECT) ||
         ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_DIRECT)) {
         struct srp_direct_buf *db = srpt_get_desc_buf(srp_cmd);
 
         *data_len = be32_to_cpu(db->len);
         return srpt_alloc_rw_ctxs(ioctx, db, 1, sg, sg_cnt);
     } else if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_INDIRECT) ||
            ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_INDIRECT)) {
         struct srp_indirect_buf *idb = srpt_get_desc_buf(srp_cmd);
         int nbufs = be32_to_cpu(idb->table_desc.len) /
                 sizeof(struct srp_direct_buf);
 
         if (nbufs >
             (srp_cmd->data_out_desc_cnt + srp_cmd->data_in_desc_cnt)) {
             pr_err("received unsupported SRP_CMD request type (%u out + %u in != %u / %zu)\n",
                    srp_cmd->data_out_desc_cnt,
                    srp_cmd->data_in_desc_cnt,
                    be32_to_cpu(idb->table_desc.len),
                    sizeof(struct srp_direct_buf));
             return -EINVAL;
         }
 
         *data_len = be32_to_cpu(idb->len);
         return srpt_alloc_rw_ctxs(ioctx, idb->desc_list, nbufs,
                 sg, sg_cnt);
     } else if ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_IMM) {
         struct srp_imm_buf *imm_buf = srpt_get_desc_buf(srp_cmd);
         void *data = (void *)srp_cmd + imm_data_offset;
         uint32_t len = be32_to_cpu(imm_buf->len);
         uint32_t req_size = imm_data_offset + len;
 
         if (req_size > srp_max_req_size) {
             pr_err("Immediate data (length %d + %d) exceeds request size %d\n",
                    imm_data_offset, len, srp_max_req_size);
             return -EINVAL;
         }
         if (recv_ioctx->byte_len < req_size) {
             pr_err("Received too few data - %d < %d\n",
                    recv_ioctx->byte_len, req_size);
             return -EIO;
         }
         /*
          * The immediate data buffer descriptor must occur before the
          * immediate data itself.
          */
         if ((void *)(imm_buf + 1) > (void *)data) {
             pr_err("Received invalid write request\n");
             return -EINVAL;
         }
         *data_len = len;
         ioctx->recv_ioctx = recv_ioctx;
         if ((uintptr_t)data & 511) {
             pr_warn_once("Internal error - the receive buffers are not aligned properly.\n");
             return -EINVAL;
         }
         sg_init_one(&ioctx->imm_sg, data, len);
         *sg = &ioctx->imm_sg;
         *sg_cnt = 1;
         return 0;
     } else {
         *data_len = 0;
         return 0;
     }
 }
 
 /**
  * srpt_init_ch_qp - initialize queue pair attributes
  * @ch: SRPT RDMA channel.
  * @qp: Queue pair pointer.
  *
  * Initialized the attributes of queue pair 'qp' by allowing local write,
  * remote read and remote write. Also transitions 'qp' to state IB_QPS_INIT.
  */
 static int srpt_init_ch_qp(struct srpt_rdma_ch *ch, struct ib_qp *qp)
 {
     struct ib_qp_attr *attr;
     int ret;
 
     WARN_ON_ONCE(ch->using_rdma_cm);
 
     attr = kzalloc(sizeof(*attr), GFP_KERNEL);
     if (!attr)
         return -ENOMEM;
 
     attr->qp_state = IB_QPS_INIT;
     attr->qp_access_flags = IB_ACCESS_LOCAL_WRITE;
     attr->port_num = ch->sport->port;
 
     ret = ib_find_cached_pkey(ch->sport->sdev->device, ch->sport->port,
                   ch->pkey, &attr->pkey_index);
     if (ret < 0)
         pr_err("Translating pkey %#x failed (%d) - using index 0\n",
                ch->pkey, ret);
 
     ret = ib_modify_qp(qp, attr,
                IB_QP_STATE | IB_QP_ACCESS_FLAGS | IB_QP_PORT |
                IB_QP_PKEY_INDEX);
 
     kfree(attr);
     return ret;
 }
 
 /**
  * srpt_ch_qp_rtr - change the state of a channel to 'ready to receive' (RTR)
  * @ch: channel of the queue pair.
  * @qp: queue pair to change the state of.
  *
  * Returns zero upon success and a negative value upon failure.
  *
  * Note: currently a struct ib_qp_attr takes 136 bytes on a 64-bit system.
  * If this structure ever becomes larger, it might be necessary to allocate
  * it dynamically instead of on the stack.
  */
 static int srpt_ch_qp_rtr(struct srpt_rdma_ch *ch, struct ib_qp *qp)
 {
     struct ib_qp_attr qp_attr;
     int attr_mask;
     int ret;
 
     WARN_ON_ONCE(ch->using_rdma_cm);
 
     qp_attr.qp_state = IB_QPS_RTR;
     ret = ib_cm_init_qp_attr(ch->ib_cm.cm_id, &qp_attr, &attr_mask);
     if (ret)
         goto out;
 
     qp_attr.max_dest_rd_atomic = 4;
 
     ret = ib_modify_qp(qp, &qp_attr, attr_mask);
 
 out:
     return ret;
 }
 
 /**
  * srpt_ch_qp_rts - change the state of a channel to 'ready to send' (RTS)
  * @ch: channel of the queue pair.
  * @qp: queue pair to change the state of.
  *
  * Returns zero upon success and a negative value upon failure.
  *
  * Note: currently a struct ib_qp_attr takes 136 bytes on a 64-bit system.
  * If this structure ever becomes larger, it might be necessary to allocate
  * it dynamically instead of on the stack.
  */
 static int srpt_ch_qp_rts(struct srpt_rdma_ch *ch, struct ib_qp *qp)
 {
     struct ib_qp_attr qp_attr;
     int attr_mask;
     int ret;
 
     qp_attr.qp_state = IB_QPS_RTS;
     ret = ib_cm_init_qp_attr(ch->ib_cm.cm_id, &qp_attr, &attr_mask);
     if (ret)
         goto out;
 
     qp_attr.max_rd_atomic = 4;
 
     ret = ib_modify_qp(qp, &qp_attr, attr_mask);
 
 out:
     return ret;
 }
 
 /**
  * srpt_ch_qp_err - set the channel queue pair state to 'error'
  * @ch: SRPT RDMA channel.
  */
 static int srpt_ch_qp_err(struct srpt_rdma_ch *ch)
 {
     struct ib_qp_attr qp_attr;
 
     qp_attr.qp_state = IB_QPS_ERR;
     return ib_modify_qp(ch->qp, &qp_attr, IB_QP_STATE);
 }
 
 /**
  * srpt_get_send_ioctx - obtain an I/O context for sending to the initiator
  * @ch: SRPT RDMA channel.
  */
 static struct srpt_send_ioctx *srpt_get_send_ioctx(struct srpt_rdma_ch *ch)
 {
     struct srpt_send_ioctx *ioctx;
     int tag, cpu;
 
     BUG_ON(!ch);
 
     tag = sbitmap_queue_get(&ch->sess->sess_tag_pool, &cpu);
     if (tag < 0)
         return NULL;
 
     ioctx = ch->ioctx_ring[tag];
     BUG_ON(ioctx->ch != ch);
     ioctx->state = SRPT_STATE_NEW;
     WARN_ON_ONCE(ioctx->recv_ioctx);
     ioctx->n_rdma = 0;
     ioctx->n_rw_ctx = 0;
     ioctx->queue_status_only = false;
     /*
      * transport_init_se_cmd() does not initialize all fields, so do it
      * here.
      */
     memset(&ioctx->cmd, 0, sizeof(ioctx->cmd));
     memset(&ioctx->sense_data, 0, sizeof(ioctx->sense_data));
     ioctx->cmd.map_tag = tag;
     ioctx->cmd.map_cpu = cpu;
 
     return ioctx;
 }
 
 /**
  * srpt_abort_cmd - abort a SCSI command
  * @ioctx:   I/O context associated with the SCSI command.
  */
 static int srpt_abort_cmd(struct srpt_send_ioctx *ioctx)
 {
     enum srpt_command_state state;
 
     BUG_ON(!ioctx);
 
     /*
      * If the command is in a state where the target core is waiting for
      * the ib_srpt driver, change the state to the next state.
      */
 
     state = ioctx->state;
     switch (state) {
     case SRPT_STATE_NEED_DATA:
         ioctx->state = SRPT_STATE_DATA_IN;
         break;
     case SRPT_STATE_CMD_RSP_SENT:
     case SRPT_STATE_MGMT_RSP_SENT:
         ioctx->state = SRPT_STATE_DONE;
         break;
     default:
         WARN_ONCE(true, "%s: unexpected I/O context state %d\n",
               __func__, state);
         break;
     }
 
     pr_debug("Aborting cmd with state %d -> %d and tag %lld\n", state,
          ioctx->state, ioctx->cmd.tag);
 
     switch (state) {
     case SRPT_STATE_NEW:
     case SRPT_STATE_DATA_IN:
     case SRPT_STATE_MGMT:
     case SRPT_STATE_DONE:
         /*
          * Do nothing - defer abort processing until
          * srpt_queue_response() is invoked.
          */
         break;
     case SRPT_STATE_NEED_DATA:
         pr_debug("tag %#llx: RDMA read error\n", ioctx->cmd.tag);
         transport_generic_request_failure(&ioctx->cmd,
                     TCM_CHECK_CONDITION_ABORT_CMD);
         break;
     case SRPT_STATE_CMD_RSP_SENT:
         /*
          * SRP_RSP sending failed or the SRP_RSP send completion has
          * not been received in time.
          */
         transport_generic_free_cmd(&ioctx->cmd, 0);
         break;
     case SRPT_STATE_MGMT_RSP_SENT:
         transport_generic_free_cmd(&ioctx->cmd, 0);
         break;
     default:
         WARN(1, "Unexpected command state (%d)", state);
         break;
     }
 
     return state;
 }
 
 /**
  * srpt_rdma_read_done - RDMA read completion callback
  * @cq: Completion queue.
  * @wc: Work completion.
  *
  * XXX: what is now target_execute_cmd used to be asynchronous, and unmapping
  * the data that has been transferred via IB RDMA had to be postponed until the
  * check_stop_free() callback.  None of this is necessary anymore and needs to
  * be cleaned up.
  */
 static void srpt_rdma_read_done(struct ib_cq *cq, struct ib_wc *wc)
 {
     struct srpt_rdma_ch *ch = wc->qp->qp_context;
     struct srpt_send_ioctx *ioctx =
         container_of(wc->wr_cqe, struct srpt_send_ioctx, rdma_cqe);
 
     WARN_ON(ioctx->n_rdma <= 0);
     atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
     ioctx->n_rdma = 0;
 
     if (unlikely(wc->status != IB_WC_SUCCESS)) {
         pr_info("RDMA_READ for ioctx 0x%p failed with status %d\n",
             ioctx, wc->status);
         srpt_abort_cmd(ioctx);
         return;
     }
 
     if (srpt_test_and_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA,
                     SRPT_STATE_DATA_IN))
         target_execute_cmd(&ioctx->cmd);
     else
         pr_err("%s[%d]: wrong state = %d\n", __func__,
                __LINE__, ioctx->state);
 }
 
 /**
  * srpt_build_cmd_rsp - build a SRP_RSP response
  * @ch: RDMA channel through which the request has been received.
  * @ioctx: I/O context associated with the SRP_CMD request. The response will
  *   be built in the buffer ioctx->buf points at and hence this function will
  *   overwrite the request data.
  * @tag: tag of the request for which this response is being generated.
  * @status: value for the STATUS field of the SRP_RSP information unit.
  *
  * Returns the size in bytes of the SRP_RSP response.
  *
  * An SRP_RSP response contains a SCSI status or service response. See also
  * section 6.9 in the SRP r16a document for the format of an SRP_RSP
  * response. See also SPC-2 for more information about sense data.
  */
 static int srpt_build_cmd_rsp(struct srpt_rdma_ch *ch,
                   struct srpt_send_ioctx *ioctx, u64 tag,
                   int status)
 {
     struct se_cmd *cmd = &ioctx->cmd;
     struct srp_rsp *srp_rsp;
     const u8 *sense_data;
     int sense_data_len, max_sense_len;
     u32 resid = cmd->residual_count;
 
     /*
      * The lowest bit of all SAM-3 status codes is zero (see also
      * paragraph 5.3 in SAM-3).
      */
     WARN_ON(status & 1);
 
     srp_rsp = ioctx->ioctx.buf;
     BUG_ON(!srp_rsp);
 
     sense_data = ioctx->sense_data;
     sense_data_len = ioctx->cmd.scsi_sense_length;
     WARN_ON(sense_data_len > sizeof(ioctx->sense_data));
 
     memset(srp_rsp, 0, sizeof(*srp_rsp));
     srp_rsp->opcode = SRP_RSP;
     srp_rsp->req_lim_delta =
         cpu_to_be32(1 + atomic_xchg(&ch->req_lim_delta, 0));
     srp_rsp->tag = tag;
     srp_rsp->status = status;
 
     if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
         if (cmd->data_direction == DMA_TO_DEVICE) {
             /* residual data from an underflow write */
             srp_rsp->flags = SRP_RSP_FLAG_DOUNDER;
             srp_rsp->data_out_res_cnt = cpu_to_be32(resid);
         } else if (cmd->data_direction == DMA_FROM_DEVICE) {
             /* residual data from an underflow read */
             srp_rsp->flags = SRP_RSP_FLAG_DIUNDER;
             srp_rsp->data_in_res_cnt = cpu_to_be32(resid);
         }
     } else if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
         if (cmd->data_direction == DMA_TO_DEVICE) {
             /* residual data from an overflow write */
             srp_rsp->flags = SRP_RSP_FLAG_DOOVER;
             srp_rsp->data_out_res_cnt = cpu_to_be32(resid);
         } else if (cmd->data_direction == DMA_FROM_DEVICE) {
             /* residual data from an overflow read */
             srp_rsp->flags = SRP_RSP_FLAG_DIOVER;
             srp_rsp->data_in_res_cnt = cpu_to_be32(resid);
         }
     }
 
     if (sense_data_len) {
         BUILD_BUG_ON(MIN_MAX_RSP_SIZE <= sizeof(*srp_rsp));
         max_sense_len = ch->max_ti_iu_len - sizeof(*srp_rsp);
         if (sense_data_len > max_sense_len) {
             pr_warn("truncated sense data from %d to %d bytes\n",
                 sense_data_len, max_sense_len);
             sense_data_len = max_sense_len;
         }
 
         srp_rsp->flags |= SRP_RSP_FLAG_SNSVALID;
         srp_rsp->sense_data_len = cpu_to_be32(sense_data_len);
         memcpy(srp_rsp + 1, sense_data, sense_data_len);
     }
 
     return sizeof(*srp_rsp) + sense_data_len;
 }
 
 /**
  * srpt_build_tskmgmt_rsp - build a task management response
  * @ch:       RDMA channel through which the request has been received.
  * @ioctx:    I/O context in which the SRP_RSP response will be built.
  * @rsp_code: RSP_CODE that will be stored in the response.
  * @tag:      Tag of the request for which this response is being generated.
  *
  * Returns the size in bytes of the SRP_RSP response.
  *
  * An SRP_RSP response contains a SCSI status or service response. See also
  * section 6.9 in the SRP r16a document for the format of an SRP_RSP
  * response.
  */
 static int srpt_build_tskmgmt_rsp(struct srpt_rdma_ch *ch,
                   struct srpt_send_ioctx *ioctx,
                   u8 rsp_code, u64 tag)
 {
     struct srp_rsp *srp_rsp;
     int resp_data_len;
     int resp_len;
 
     resp_data_len = 4;
     resp_len = sizeof(*srp_rsp) + resp_data_len;
 
     srp_rsp = ioctx->ioctx.buf;
     BUG_ON(!srp_rsp);
     memset(srp_rsp, 0, sizeof(*srp_rsp));
 
     srp_rsp->opcode = SRP_RSP;
     srp_rsp->req_lim_delta =
         cpu_to_be32(1 + atomic_xchg(&ch->req_lim_delta, 0));
     srp_rsp->tag = tag;
 
     srp_rsp->flags |= SRP_RSP_FLAG_RSPVALID;
     srp_rsp->resp_data_len = cpu_to_be32(resp_data_len);
     srp_rsp->data[3] = rsp_code;
 
     return resp_len;
 }
 
 static int srpt_check_stop_free(struct se_cmd *cmd)
 {
     struct srpt_send_ioctx *ioctx = container_of(cmd,
                 struct srpt_send_ioctx, cmd);
 
     return target_put_sess_cmd(&ioctx->cmd);
 }
 
 /**
  * srpt_handle_cmd - process a SRP_CMD information unit
  * @ch: SRPT RDMA channel.
  * @recv_ioctx: Receive I/O context.
  * @send_ioctx: Send I/O context.
  */
 static void srpt_handle_cmd(struct srpt_rdma_ch *ch,
                 struct srpt_recv_ioctx *recv_ioctx,
                 struct srpt_send_ioctx *send_ioctx)
 {
     struct se_cmd *cmd;
     struct srp_cmd *srp_cmd;
     struct scatterlist *sg = NULL;
     unsigned sg_cnt = 0;
     u64 data_len;
     enum dma_data_direction dir;
     int rc;
 
     BUG_ON(!send_ioctx);
 
     srp_cmd = recv_ioctx->ioctx.buf + recv_ioctx->ioctx.offset;
     cmd = &send_ioctx->cmd;
     cmd->tag = srp_cmd->tag;
 
     switch (srp_cmd->task_attr) {
     case SRP_CMD_SIMPLE_Q:
         cmd->sam_task_attr = TCM_SIMPLE_TAG;
         break;
     case SRP_CMD_ORDERED_Q:
     default:
         cmd->sam_task_attr = TCM_ORDERED_TAG;
         break;
     case SRP_CMD_HEAD_OF_Q:
         cmd->sam_task_attr = TCM_HEAD_TAG;
         break;
     case SRP_CMD_ACA:
         cmd->sam_task_attr = TCM_ACA_TAG;
         break;
     }
 
     rc = srpt_get_desc_tbl(recv_ioctx, send_ioctx, srp_cmd, &dir,
                    &sg, &sg_cnt, &data_len, ch->imm_data_offset);
     if (rc) {
         if (rc != -EAGAIN) {
             pr_err("0x%llx: parsing SRP descriptor table failed.\n",
                    srp_cmd->tag);
         }
         goto busy;
     }
 
     rc = target_init_cmd(cmd, ch->sess, &send_ioctx->sense_data[0],
                  scsilun_to_int(&srp_cmd->lun), data_len,
                  TCM_SIMPLE_TAG, dir, TARGET_SCF_ACK_KREF);
     if (rc != 0) {
         pr_debug("target_submit_cmd() returned %d for tag %#llx\n", rc,
              srp_cmd->tag);
         goto busy;
     }
 
     if (target_submit_prep(cmd, srp_cmd->cdb, sg, sg_cnt, NULL, 0, NULL, 0,
                    GFP_KERNEL))
         return;
 
     target_submit(cmd);
     return;
 
 busy:
     target_send_busy(cmd);
 }
 
 static int srp_tmr_to_tcm(int fn)
 {
     switch (fn) {
     case SRP_TSK_ABORT_TASK:
         return TMR_ABORT_TASK;
     case SRP_TSK_ABORT_TASK_SET:
         return TMR_ABORT_TASK_SET;
     case SRP_TSK_CLEAR_TASK_SET:
         return TMR_CLEAR_TASK_SET;
     case SRP_TSK_LUN_RESET:
         return TMR_LUN_RESET;
     case SRP_TSK_CLEAR_ACA:
         return TMR_CLEAR_ACA;
     default:
         return -1;
     }
 }
 
 /**
  * srpt_handle_tsk_mgmt - process a SRP_TSK_MGMT information unit
  * @ch: SRPT RDMA channel.
  * @recv_ioctx: Receive I/O context.
  * @send_ioctx: Send I/O context.
  *
  * Returns 0 if and only if the request will be processed by the target core.
  *
  * For more information about SRP_TSK_MGMT information units, see also section
  * 6.7 in the SRP r16a document.
  */
 static void srpt_handle_tsk_mgmt(struct srpt_rdma_ch *ch,
                  struct srpt_recv_ioctx *recv_ioctx,
                  struct srpt_send_ioctx *send_ioctx)
 {
     struct srp_tsk_mgmt *srp_tsk;
     struct se_cmd *cmd;
     struct se_session *sess = ch->sess;
     int tcm_tmr;
     int rc;
 
     BUG_ON(!send_ioctx);
 
     srp_tsk = recv_ioctx->ioctx.buf + recv_ioctx->ioctx.offset;
     cmd = &send_ioctx->cmd;
 
     pr_debug("recv tsk_mgmt fn %d for task_tag %lld and cmd tag %lld ch %p sess %p\n",
          srp_tsk->tsk_mgmt_func, srp_tsk->task_tag, srp_tsk->tag, ch,
          ch->sess);
 
     srpt_set_cmd_state(send_ioctx, SRPT_STATE_MGMT);
     send_ioctx->cmd.tag = srp_tsk->tag;
     tcm_tmr = srp_tmr_to_tcm(srp_tsk->tsk_mgmt_func);
     rc = target_submit_tmr(&send_ioctx->cmd, sess, NULL,
                    scsilun_to_int(&srp_tsk->lun), srp_tsk, tcm_tmr,
                    GFP_KERNEL, srp_tsk->task_tag,
                    TARGET_SCF_ACK_KREF);
     if (rc != 0) {
         send_ioctx->cmd.se_tmr_req->response = TMR_FUNCTION_REJECTED;
         cmd->se_tfo->queue_tm_rsp(cmd);
     }
     return;
 }
 
 /**
  * srpt_handle_new_iu - process a newly received information unit
  * @ch:    RDMA channel through which the information unit has been received.
  * @recv_ioctx: Receive I/O context associated with the information unit.
  */
 static bool
 srpt_handle_new_iu(struct srpt_rdma_ch *ch, struct srpt_recv_ioctx *recv_ioctx)
 {
     struct srpt_send_ioctx *send_ioctx = NULL;
     struct srp_cmd *srp_cmd;
     bool res = false;
     u8 opcode;
 
     BUG_ON(!ch);
     BUG_ON(!recv_ioctx);
 
     if (unlikely(ch->state == CH_CONNECTING))
         goto push;
 
     ib_dma_sync_single_for_cpu(ch->sport->sdev->device,
                    recv_ioctx->ioctx.dma,
                    recv_ioctx->ioctx.offset + srp_max_req_size,
                    DMA_FROM_DEVICE);
 
     srp_cmd = recv_ioctx->ioctx.buf + recv_ioctx->ioctx.offset;
     opcode = srp_cmd->opcode;
     if (opcode == SRP_CMD || opcode == SRP_TSK_MGMT) {
         send_ioctx = srpt_get_send_ioctx(ch);
         if (unlikely(!send_ioctx))
             goto push;
     }
 
     if (!list_empty(&recv_ioctx->wait_list)) {
         WARN_ON_ONCE(!ch->processing_wait_list);
         list_del_init(&recv_ioctx->wait_list);
     }
 
     switch (opcode) {
     case SRP_CMD:
         srpt_handle_cmd(ch, recv_ioctx, send_ioctx);
         break;
     case SRP_TSK_MGMT:
         srpt_handle_tsk_mgmt(ch, recv_ioctx, send_ioctx);
         break;
     case SRP_I_LOGOUT:
         pr_err("Not yet implemented: SRP_I_LOGOUT\n");
         break;
     case SRP_CRED_RSP:
         pr_debug("received SRP_CRED_RSP\n");
         break;
     case SRP_AER_RSP:
         pr_debug("received SRP_AER_RSP\n");
         break;
     case SRP_RSP:
         pr_err("Received SRP_RSP\n");
         break;
     default:
         pr_err("received IU with unknown opcode 0x%x\n", opcode);
         break;
     }
 
     if (!send_ioctx || !send_ioctx->recv_ioctx)
         srpt_post_recv(ch->sport->sdev, ch, recv_ioctx);
     res = true;
 
 out:
     return res;
 
 push:
     if (list_empty(&recv_ioctx->wait_list)) {
         WARN_ON_ONCE(ch->processing_wait_list);
         list_add_tail(&recv_ioctx->wait_list, &ch->cmd_wait_list);
     }
     goto out;
 }
 
 static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc)
 {
     struct srpt_rdma_ch *ch = wc->qp->qp_context;
     struct srpt_recv_ioctx *ioctx =
         container_of(wc->wr_cqe, struct srpt_recv_ioctx, ioctx.cqe);
 
     if (wc->status == IB_WC_SUCCESS) {
         int req_lim;
 
         req_lim = atomic_dec_return(&ch->req_lim);
         if (unlikely(req_lim < 0))
             pr_err("req_lim = %d < 0\n", req_lim);
         ioctx->byte_len = wc->byte_len;
         srpt_handle_new_iu(ch, ioctx);
     } else {
         pr_info_ratelimited("receiving failed for ioctx %p with status %d\n",
                     ioctx, wc->status);
     }
 }
 
 /*
  * This function must be called from the context in which RDMA completions are
  * processed because it accesses the wait list without protection against
  * access from other threads.
  */
 static void srpt_process_wait_list(struct srpt_rdma_ch *ch)
 {
     struct srpt_recv_ioctx *recv_ioctx, *tmp;
 
     WARN_ON_ONCE(ch->state == CH_CONNECTING);
 
     if (list_empty(&ch->cmd_wait_list))
         return;
 
     WARN_ON_ONCE(ch->processing_wait_list);
     ch->processing_wait_list = true;
     list_for_each_entry_safe(recv_ioctx, tmp, &ch->cmd_wait_list,
                  wait_list) {
         if (!srpt_handle_new_iu(ch, recv_ioctx))
             break;
     }
     ch->processing_wait_list = false;
 }
 
 /**
  * srpt_send_done - send completion callback
  * @cq: Completion queue.
  * @wc: Work completion.
  *
  * Note: Although this has not yet been observed during tests, at least in
  * theory it is possible that the srpt_get_send_ioctx() call invoked by
  * srpt_handle_new_iu() fails. This is possible because the req_lim_delta
  * value in each response is set to one, and it is possible that this response
  * makes the initiator send a new request before the send completion for that
  * response has been processed. This could e.g. happen if the call to
  * srpt_put_send_iotcx() is delayed because of a higher priority interrupt or
  * if IB retransmission causes generation of the send completion to be
  * delayed. Incoming information units for which srpt_get_send_ioctx() fails
  * are queued on cmd_wait_list. The code below processes these delayed
  * requests one at a time.
  */
 static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc)
 {
     struct srpt_rdma_ch *ch = wc->qp->qp_context;
     struct srpt_send_ioctx *ioctx =
         container_of(wc->wr_cqe, struct srpt_send_ioctx, ioctx.cqe);
     enum srpt_command_state state;
 
     state = srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
 
     WARN_ON(state != SRPT_STATE_CMD_RSP_SENT &&
         state != SRPT_STATE_MGMT_RSP_SENT);
 
     atomic_add(1 + ioctx->n_rdma, &ch->sq_wr_avail);
 
     if (wc->status != IB_WC_SUCCESS)
         pr_info("sending response for ioctx 0x%p failed with status %d\n",
             ioctx, wc->status);
 
     if (state != SRPT_STATE_DONE) {
         transport_generic_free_cmd(&ioctx->cmd, 0);
     } else {
         pr_err("IB completion has been received too late for wr_id = %u.\n",
                ioctx->ioctx.index);
     }
 
     srpt_process_wait_list(ch);
 }
 
 /**
  * srpt_create_ch_ib - create receive and send completion queues
  * @ch: SRPT RDMA channel.
  */
 static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
 {
     struct ib_qp_init_attr *qp_init;
     struct srpt_port *sport = ch->sport;
     struct srpt_device *sdev = sport->sdev;
     const struct ib_device_attr *attrs = &sdev->device->attrs;
     int sq_size = sport->port_attrib.srp_sq_size;
     int i, ret;
 
     WARN_ON(ch->rq_size < 1);
 
     ret = -ENOMEM;
     qp_init = kzalloc(sizeof(*qp_init), GFP_KERNEL);
     if (!qp_init)
         goto out;
 
 retry:
     ch->cq = ib_cq_pool_get(sdev->device, ch->rq_size + sq_size, -1,
                  IB_POLL_WORKQUEUE);
     if (IS_ERR(ch->cq)) {
         ret = PTR_ERR(ch->cq);
         pr_err("failed to create CQ cqe= %d ret= %d\n",
                ch->rq_size + sq_size, ret);
         goto out;
     }
     ch->cq_size = ch->rq_size + sq_size;
 
     qp_init->qp_context = (void *)ch;
     qp_init->event_handler
         = (void(*)(struct ib_event *, void*))srpt_qp_event;
     qp_init->send_cq = ch->cq;
     qp_init->recv_cq = ch->cq;
     qp_init->sq_sig_type = IB_SIGNAL_REQ_WR;
     qp_init->qp_type = IB_QPT_RC;
     /*
      * We divide up our send queue size into half SEND WRs to send the
      * completions, and half R/W contexts to actually do the RDMA
      * READ/WRITE transfers.  Note that we need to allocate CQ slots for
      * both both, as RDMA contexts will also post completions for the
      * RDMA READ case.
      */
     qp_init->cap.max_send_wr = min(sq_size / 2, attrs->max_qp_wr);
     qp_init->cap.max_rdma_ctxs = sq_size / 2;
     qp_init->cap.max_send_sge = attrs->max_send_sge;
     qp_init->cap.max_recv_sge = 1;
     qp_init->port_num = ch->sport->port;
     if (sdev->use_srq)
         qp_init->srq = sdev->srq;
     else
         qp_init->cap.max_recv_wr = ch->rq_size;
 
     if (ch->using_rdma_cm) {
         ret = rdma_create_qp(ch->rdma_cm.cm_id, sdev->pd, qp_init);
         ch->qp = ch->rdma_cm.cm_id->qp;
     } else {
         ch->qp = ib_create_qp(sdev->pd, qp_init);
         if (!IS_ERR(ch->qp)) {
             ret = srpt_init_ch_qp(ch, ch->qp);
             if (ret)
                 ib_destroy_qp(ch->qp);
         } else {
             ret = PTR_ERR(ch->qp);
         }
     }
     if (ret) {
         bool retry = sq_size > MIN_SRPT_SQ_SIZE;
 
         if (retry) {
             pr_debug("failed to create queue pair with sq_size = %d (%d) - retrying\n",
                  sq_size, ret);
             ib_cq_pool_put(ch->cq, ch->cq_size);
             sq_size = max(sq_size / 2, MIN_SRPT_SQ_SIZE);
             goto retry;
         } else {
             pr_err("failed to create queue pair with sq_size = %d (%d)\n",
                    sq_size, ret);
             goto err_destroy_cq;
         }
     }
 
     atomic_set(&ch->sq_wr_avail, qp_init->cap.max_send_wr);
 
     pr_debug("%s: max_cqe= %d max_sge= %d sq_size = %d ch= %p\n",
          __func__, ch->cq->cqe, qp_init->cap.max_send_sge,
          qp_init->cap.max_send_wr, ch);
 
     if (!sdev->use_srq)
         for (i = 0; i < ch->rq_size; i++)
             srpt_post_recv(sdev, ch, ch->ioctx_recv_ring[i]);
 
 out:
     kfree(qp_init);
     return ret;
 
 err_destroy_cq:
     ch->qp = NULL;
     ib_cq_pool_put(ch->cq, ch->cq_size);
     goto out;
 }
 
 static void srpt_destroy_ch_ib(struct srpt_rdma_ch *ch)
 {
     ib_destroy_qp(ch->qp);
     ib_cq_pool_put(ch->cq, ch->cq_size);
 }
 
 /**
  * srpt_close_ch - close a RDMA channel
  * @ch: SRPT RDMA channel.
  *
  * Make sure all resources associated with the channel will be deallocated at
  * an appropriate time.
  *
  * Returns true if and only if the channel state has been modified into
  * CH_DRAINING.
  */
 static bool srpt_close_ch(struct srpt_rdma_ch *ch)
 {
     int ret;
 
     if (!srpt_set_ch_state(ch, CH_DRAINING)) {
         pr_debug("%s: already closed\n", ch->sess_name);
         return false;
     }
 
     kref_get(&ch->kref);
 
     ret = srpt_ch_qp_err(ch);
     if (ret < 0)
         pr_err("%s-%d: changing queue pair into error state failed: %d\n",
                ch->sess_name, ch->qp->qp_num, ret);
 
     ret = srpt_zerolength_write(ch);
     if (ret < 0) {
         pr_err("%s-%d: queuing zero-length write failed: %d\n",
                ch->sess_name, ch->qp->qp_num, ret);
         if (srpt_set_ch_state(ch, CH_DISCONNECTED))
             schedule_work(&ch->release_work);
         else
             WARN_ON_ONCE(true);
     }
 
     kref_put(&ch->kref, srpt_free_ch);
 
     return true;
 }
 
 /*
  * Change the channel state into CH_DISCONNECTING. If a channel has not yet
  * reached the connected state, close it. If a channel is in the connected
  * state, send a DREQ. If a DREQ has been received, send a DREP. Note: it is
  * the responsibility of the caller to ensure that this function is not
  * invoked concurrently with the code that accepts a connection. This means
  * that this function must either be invoked from inside a CM callback
  * function or that it must be invoked with the srpt_port.mutex held.
  */
 static int srpt_disconnect_ch(struct srpt_rdma_ch *ch)
 {
     int ret;
 
     if (!srpt_set_ch_state(ch, CH_DISCONNECTING))
         return -ENOTCONN;
 
     if (ch->using_rdma_cm) {
         ret = rdma_disconnect(ch->rdma_cm.cm_id);
     } else {
         ret = ib_send_cm_dreq(ch->ib_cm.cm_id, NULL, 0);
         if (ret < 0)
             ret = ib_send_cm_drep(ch->ib_cm.cm_id, NULL, 0);
     }
 
     if (ret < 0 && srpt_close_ch(ch))
         ret = 0;
 
     return ret;
 }
 
 /* Send DREQ and wait for DREP. */
 static void srpt_disconnect_ch_sync(struct srpt_rdma_ch *ch)
 {
     DECLARE_COMPLETION_ONSTACK(closed);
     struct srpt_port *sport = ch->sport;
 
     pr_debug("ch %s-%d state %d\n", ch->sess_name, ch->qp->qp_num,
          ch->state);
 
     ch->closed = &closed;
 
     mutex_lock(&sport->mutex);
     srpt_disconnect_ch(ch);
     mutex_unlock(&sport->mutex);
 
     while (wait_for_completion_timeout(&closed, 5 * HZ) == 0)
         pr_info("%s(%s-%d state %d): still waiting ...\n", __func__,
             ch->sess_name, ch->qp->qp_num, ch->state);
 
 }
 
 static void __srpt_close_all_ch(struct srpt_port *sport)
 {
     struct srpt_nexus *nexus;
     struct srpt_rdma_ch *ch;
 
     lockdep_assert_held(&sport->mutex);
 
     list_for_each_entry(nexus, &sport->nexus_list, entry) {
         list_for_each_entry(ch, &nexus->ch_list, list) {
             if (srpt_disconnect_ch(ch) >= 0)
                 pr_info("Closing channel %s-%d because target %s_%d has been disabled\n",
                     ch->sess_name, ch->qp->qp_num,
                     dev_name(&sport->sdev->device->dev),
                     sport->port);
             srpt_close_ch(ch);
         }
     }
 }
 
 /*
  * Look up (i_port_id, t_port_id) in sport->nexus_list. Create an entry if
  * it does not yet exist.
  */
 static struct srpt_nexus *srpt_get_nexus(struct srpt_port *sport,
                      const u8 i_port_id[16],
                      const u8 t_port_id[16])
 {
     struct srpt_nexus *nexus = NULL, *tmp_nexus = NULL, *n;
 
     for (;;) {
         mutex_lock(&sport->mutex);
         list_for_each_entry(n, &sport->nexus_list, entry) {
             if (memcmp(n->i_port_id, i_port_id, 16) == 0 &&
                 memcmp(n->t_port_id, t_port_id, 16) == 0) {
                 nexus = n;
                 break;
             }
         }
         if (!nexus && tmp_nexus) {
             list_add_tail_rcu(&tmp_nexus->entry,
                       &sport->nexus_list);
             swap(nexus, tmp_nexus);
         }
         mutex_unlock(&sport->mutex);
 
         if (nexus)
             break;
         tmp_nexus = kzalloc(sizeof(*nexus), GFP_KERNEL);
         if (!tmp_nexus) {
             nexus = ERR_PTR(-ENOMEM);
             break;
         }
         INIT_LIST_HEAD(&tmp_nexus->ch_list);
         memcpy(tmp_nexus->i_port_id, i_port_id, 16);
         memcpy(tmp_nexus->t_port_id, t_port_id, 16);
     }
 
     kfree(tmp_nexus);
 
     return nexus;
 }
 
 static void srpt_set_enabled(struct srpt_port *sport, bool enabled)
     __must_hold(&sport->mutex)
 {
     lockdep_assert_held(&sport->mutex);
 
     if (sport->enabled == enabled)
         return;
     sport->enabled = enabled;
     if (!enabled)
         __srpt_close_all_ch(sport);
 }
 
 static void srpt_drop_sport_ref(struct srpt_port *sport)
 {
     if (atomic_dec_return(&sport->refcount) == 0 && sport->freed_channels)
         complete(sport->freed_channels);
 }
 
 static void srpt_free_ch(struct kref *kref)
 {
     struct srpt_rdma_ch *ch = container_of(kref, struct srpt_rdma_ch, kref);
 
     srpt_drop_sport_ref(ch->sport);
     kfree_rcu(ch, rcu);
 }
 
 /*
  * Shut down the SCSI target session, tell the connection manager to
  * disconnect the associated RDMA channel, transition the QP to the error
  * state and remove the channel from the channel list. This function is
  * typically called from inside srpt_zerolength_write_done(). Concurrent
  * srpt_zerolength_write() calls from inside srpt_close_ch() are possible
  * as long as the channel is on sport->nexus_list.
  */
 static void srpt_release_channel_work(struct work_struct *w)
 {
     struct srpt_rdma_ch *ch;
     struct srpt_device *sdev;
     struct srpt_port *sport;
     struct se_session *se_sess;
 
     ch = container_of(w, struct srpt_rdma_ch, release_work);
     pr_debug("%s-%d\n", ch->sess_name, ch->qp->qp_num);
 
     sdev = ch->sport->sdev;
     BUG_ON(!sdev);
 
     se_sess = ch->sess;
     BUG_ON(!se_sess);
 
     target_stop_session(se_sess);
     target_wait_for_sess_cmds(se_sess);
 
     target_remove_session(se_sess);
     ch->sess = NULL;
 
     if (ch->using_rdma_cm)
         rdma_destroy_id(ch->rdma_cm.cm_id);
     else
         ib_destroy_cm_id(ch->ib_cm.cm_id);
 
     sport = ch->sport;
     mutex_lock(&sport->mutex);
     list_del_rcu(&ch->list);
     mutex_unlock(&sport->mutex);
 
     if (ch->closed)
         complete(ch->closed);
 
     srpt_destroy_ch_ib(ch);
 
     srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
                  ch->sport->sdev, ch->rq_size,
                  ch->rsp_buf_cache, DMA_TO_DEVICE);
 
     kmem_cache_destroy(ch->rsp_buf_cache);
 
     srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_recv_ring,
                  sdev, ch->rq_size,
                  ch->req_buf_cache, DMA_FROM_DEVICE);
 
     kmem_cache_destroy(ch->req_buf_cache);
 
     kref_put(&ch->kref, srpt_free_ch);
 }
 
 /**
  * srpt_cm_req_recv - process the event IB_CM_REQ_RECEIVED
  * @sdev: HCA through which the login request was received.
  * @ib_cm_id: IB/CM connection identifier in case of IB/CM.
  * @rdma_cm_id: RDMA/CM connection identifier in case of RDMA/CM.
  * @port_num: Port through which the REQ message was received.
  * @pkey: P_Key of the incoming connection.
  * @req: SRP login request.
  * @src_addr: GID (IB/CM) or IP address (RDMA/CM) of the port that submitted
  * the login request.
  *
  * Ownership of the cm_id is transferred to the target session if this
  * function returns zero. Otherwise the caller remains the owner of cm_id.
  */
 static int srpt_cm_req_recv(struct srpt_device *const sdev,
                 struct ib_cm_id *ib_cm_id,
                 struct rdma_cm_id *rdma_cm_id,
                 u8 port_num, __be16 pkey,
                 const struct srp_login_req *req,
                 const char *src_addr)
 {
     struct srpt_port *sport = &sdev->port[port_num - 1];
     struct srpt_nexus *nexus;
     struct srp_login_rsp *rsp = NULL;
     struct srp_login_rej *rej = NULL;
     union {
         struct rdma_conn_param rdma_cm;
         struct ib_cm_rep_param ib_cm;
     } *rep_param = NULL;
     struct srpt_rdma_ch *ch = NULL;
     char i_port_id[36];
     u32 it_iu_len;
     int i, tag_num, tag_size, ret;
     struct srpt_tpg *stpg;
 
     WARN_ON_ONCE(irqs_disabled());
 
     it_iu_len = be32_to_cpu(req->req_it_iu_len);
 
     pr_info("Received SRP_LOGIN_REQ with i_port_id %pI6, t_port_id %pI6 and it_iu_len %d on port %d (guid=%pI6); pkey %#04x\n",
         req->initiator_port_id, req->target_port_id, it_iu_len,
         port_num, &sport->gid, be16_to_cpu(pkey));
 
     nexus = srpt_get_nexus(sport, req->initiator_port_id,
                    req->target_port_id);
     if (IS_ERR(nexus)) {
         ret = PTR_ERR(nexus);
         goto out;
     }
 
     ret = -ENOMEM;
     rsp = kzalloc(sizeof(*rsp), GFP_KERNEL);
     rej = kzalloc(sizeof(*rej), GFP_KERNEL);
     rep_param = kzalloc(sizeof(*rep_param), GFP_KERNEL);
     if (!rsp || !rej || !rep_param)
         goto out;
 
     ret = -EINVAL;
     if (it_iu_len > srp_max_req_size || it_iu_len < 64) {
         rej->reason = cpu_to_be32(
                 SRP_LOGIN_REJ_REQ_IT_IU_LENGTH_TOO_LARGE);
         pr_err("rejected SRP_LOGIN_REQ because its length (%d bytes) is out of range (%d .. %d)\n",
                it_iu_len, 64, srp_max_req_size);
         goto reject;
     }
 
     if (!sport->enabled) {
         rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
         pr_info("rejected SRP_LOGIN_REQ because target port %s_%d has not yet been enabled\n",
             dev_name(&sport->sdev->device->dev), port_num);
         goto reject;
     }
 
     if (*(__be64 *)req->target_port_id != cpu_to_be64(srpt_service_guid)
         || *(__be64 *)(req->target_port_id + 8) !=
            cpu_to_be64(srpt_service_guid)) {
         rej->reason = cpu_to_be32(
                 SRP_LOGIN_REJ_UNABLE_ASSOCIATE_CHANNEL);
         pr_err("rejected SRP_LOGIN_REQ because it has an invalid target port identifier.\n");
         goto reject;
     }
 
     ret = -ENOMEM;
     ch = kzalloc(sizeof(*ch), GFP_KERNEL);
     if (!ch) {
         rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
         pr_err("rejected SRP_LOGIN_REQ because out of memory.\n");
         goto reject;
     }
 
     kref_init(&ch->kref);
     ch->pkey = be16_to_cpu(pkey);
     ch->nexus = nexus;
     ch->zw_cqe.done = srpt_zerolength_write_done;
     INIT_WORK(&ch->release_work, srpt_release_channel_work);
     ch->sport = sport;
     if (rdma_cm_id) {
         ch->using_rdma_cm = true;
         ch->rdma_cm.cm_id = rdma_cm_id;
         rdma_cm_id->context = ch;
     } else {
         ch->ib_cm.cm_id = ib_cm_id;
         ib_cm_id->context = ch;
     }
     /*
      * ch->rq_size should be at least as large as the initiator queue
      * depth to avoid that the initiator driver has to report QUEUE_FULL
      * to the SCSI mid-layer.
      */
     ch->rq_size = min(MAX_SRPT_RQ_SIZE, sdev->device->attrs.max_qp_wr);
     spin_lock_init(&ch->spinlock);
     ch->state = CH_CONNECTING;
     INIT_LIST_HEAD(&ch->cmd_wait_list);
     ch->max_rsp_size = ch->sport->port_attrib.srp_max_rsp_size;
 
     ch->rsp_buf_cache = kmem_cache_create("srpt-rsp-buf", ch->max_rsp_size,
                           512, 0, NULL);
     if (!ch->rsp_buf_cache)
         goto free_ch;
 
     ch->ioctx_ring = (struct srpt_send_ioctx **)
         srpt_alloc_ioctx_ring(ch->sport->sdev, ch->rq_size,
                       sizeof(*ch->ioctx_ring[0]),
                       ch->rsp_buf_cache, 0, DMA_TO_DEVICE);
     if (!ch->ioctx_ring) {
         pr_err("rejected SRP_LOGIN_REQ because creating a new QP SQ ring failed.\n");
         rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
         goto free_rsp_cache;
     }
 
     for (i = 0; i < ch->rq_size; i++)
         ch->ioctx_ring[i]->ch = ch;
     if (!sdev->use_srq) {
         u16 imm_data_offset = req->req_flags & SRP_IMMED_REQUESTED ?
             be16_to_cpu(req->imm_data_offset) : 0;
         u16 alignment_offset;
         u32 req_sz;
 
         if (req->req_flags & SRP_IMMED_REQUESTED)
             pr_debug("imm_data_offset = %d\n",
                  be16_to_cpu(req->imm_data_offset));
         if (imm_data_offset >= sizeof(struct srp_cmd)) {
             ch->imm_data_offset = imm_data_offset;
             rsp->rsp_flags |= SRP_LOGIN_RSP_IMMED_SUPP;
         } else {
             ch->imm_data_offset = 0;
         }
         alignment_offset = round_up(imm_data_offset, 512) -
             imm_data_offset;
         req_sz = alignment_offset + imm_data_offset + srp_max_req_size;
         ch->req_buf_cache = kmem_cache_create("srpt-req-buf", req_sz,
                               512, 0, NULL);
         if (!ch->req_buf_cache)
             goto free_rsp_ring;
 
         ch->ioctx_recv_ring = (struct srpt_recv_ioctx **)
             srpt_alloc_ioctx_ring(ch->sport->sdev, ch->rq_size,
                           sizeof(*ch->ioctx_recv_ring[0]),
                           ch->req_buf_cache,
                           alignment_offset,
                           DMA_FROM_DEVICE);
         if (!ch->ioctx_recv_ring) {
             pr_err("rejected SRP_LOGIN_REQ because creating a new QP RQ ring failed.\n");
             rej->reason =
                 cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
             goto free_recv_cache;
         }
         for (i = 0; i < ch->rq_size; i++)
             INIT_LIST_HEAD(&ch->ioctx_recv_ring[i]->wait_list);
     }
 
     ret = srpt_create_ch_ib(ch);
     if (ret) {
         rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
         pr_err("rejected SRP_LOGIN_REQ because creating a new RDMA channel failed.\n");
         goto free_recv_ring;
     }
 
     strlcpy(ch->sess_name, src_addr, sizeof(ch->sess_name));
     snprintf(i_port_id, sizeof(i_port_id), "0x%016llx%016llx",
             be64_to_cpu(*(__be64 *)nexus->i_port_id),
             be64_to_cpu(*(__be64 *)(nexus->i_port_id + 8)));
 
     pr_debug("registering src addr %s or i_port_id %s\n", ch->sess_name,
          i_port_id);
 
     tag_num = ch->rq_size;
     tag_size = 1; /* ib_srpt does not use se_sess->sess_cmd_map */
 
     if (sport->guid_id) {
         mutex_lock(&sport->guid_id->mutex);
         list_for_each_entry(stpg, &sport->guid_id->tpg_list, entry) {
             if (!IS_ERR_OR_NULL(ch->sess))
                 break;
             ch->sess = target_setup_session(&stpg->tpg, tag_num,
                         tag_size, TARGET_PROT_NORMAL,
                         ch->sess_name, ch, NULL);
         }
         mutex_unlock(&sport->guid_id->mutex);
     }
 
     if (sport->gid_id) {
         mutex_lock(&sport->gid_id->mutex);
         list_for_each_entry(stpg, &sport->gid_id->tpg_list, entry) {
             if (!IS_ERR_OR_NULL(ch->sess))
                 break;
             ch->sess = target_setup_session(&stpg->tpg, tag_num,
                     tag_size, TARGET_PROT_NORMAL, i_port_id,
                     ch, NULL);
             if (!IS_ERR_OR_NULL(ch->sess))
                 break;
             /* Retry without leading "0x" */
             ch->sess = target_setup_session(&stpg->tpg, tag_num,
                         tag_size, TARGET_PROT_NORMAL,
                         i_port_id + 2, ch, NULL);
         }
         mutex_unlock(&sport->gid_id->mutex);
     }
 
     if (IS_ERR_OR_NULL(ch->sess)) {
         WARN_ON_ONCE(ch->sess == NULL);
         ret = PTR_ERR(ch->sess);
         ch->sess = NULL;
         pr_info("Rejected login for initiator %s: ret = %d.\n",
             ch->sess_name, ret);
         rej->reason = cpu_to_be32(ret == -ENOMEM ?
                 SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES :
                 SRP_LOGIN_REJ_CHANNEL_LIMIT_REACHED);
         goto destroy_ib;
     }
 
     /*
      * Once a session has been created destruction of srpt_rdma_ch objects
      * will decrement sport->refcount. Hence increment sport->refcount now.
      */
     atomic_inc(&sport->refcount);
 
     mutex_lock(&sport->mutex);
 
     if ((req->req_flags & SRP_MTCH_ACTION) == SRP_MULTICHAN_SINGLE) {
         struct srpt_rdma_ch *ch2;
 
         list_for_each_entry(ch2, &nexus->ch_list, list) {
             if (srpt_disconnect_ch(ch2) < 0)
                 continue;
             pr_info("Relogin - closed existing channel %s\n",
                 ch2->sess_name);
             rsp->rsp_flags |= SRP_LOGIN_RSP_MULTICHAN_TERMINATED;
         }
     } else {
         rsp->rsp_flags |= SRP_LOGIN_RSP_MULTICHAN_MAINTAINED;
     }
 
     list_add_tail_rcu(&ch->list, &nexus->ch_list);
 
     if (!sport->enabled) {
         rej->reason = cpu_to_be32(
                 SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
         pr_info("rejected SRP_LOGIN_REQ because target %s_%d is not enabled\n",
             dev_name(&sdev->device->dev), port_num);
         mutex_unlock(&sport->mutex);
         ret = -EINVAL;
         goto reject;
     }
 
     mutex_unlock(&sport->mutex);
 
     ret = ch->using_rdma_cm ? 0 : srpt_ch_qp_rtr(ch, ch->qp);
     if (ret) {
         rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
         pr_err("rejected SRP_LOGIN_REQ because enabling RTR failed (error code = %d)\n",
                ret);
         goto reject;
     }
 
     pr_debug("Establish connection sess=%p name=%s ch=%p\n", ch->sess,
          ch->sess_name, ch);
 
     /* create srp_login_response */
     rsp->opcode = SRP_LOGIN_RSP;
     rsp->tag = req->tag;
     rsp->max_it_iu_len = cpu_to_be32(srp_max_req_size);
     rsp->max_ti_iu_len = req->req_it_iu_len;
     ch->max_ti_iu_len = it_iu_len;
     rsp->buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT |
                    SRP_BUF_FORMAT_INDIRECT);
     rsp->req_lim_delta = cpu_to_be32(ch->rq_size);
     atomic_set(&ch->req_lim, ch->rq_size);
     atomic_set(&ch->req_lim_delta, 0);
 
     /* create cm reply */
     if (ch->using_rdma_cm) {
         rep_param->rdma_cm.private_data = (void *)rsp;
         rep_param->rdma_cm.private_data_len = sizeof(*rsp);
         rep_param->rdma_cm.rnr_retry_count = 7;
         rep_param->rdma_cm.flow_control = 1;
         rep_param->rdma_cm.responder_resources = 4;
         rep_param->rdma_cm.initiator_depth = 4;
     } else {
         rep_param->ib_cm.qp_num = ch->qp->qp_num;
         rep_param->ib_cm.private_data = (void *)rsp;
         rep_param->ib_cm.private_data_len = sizeof(*rsp);
         rep_param->ib_cm.rnr_retry_count = 7;
         rep_param->ib_cm.flow_control = 1;
         rep_param->ib_cm.failover_accepted = 0;
         rep_param->ib_cm.srq = 1;
         rep_param->ib_cm.responder_resources = 4;
         rep_param->ib_cm.initiator_depth = 4;
     }
 
     /*
      * Hold the sport mutex while accepting a connection to avoid that
      * srpt_disconnect_ch() is invoked concurrently with this code.
      */
     mutex_lock(&sport->mutex);
     if (sport->enabled && ch->state == CH_CONNECTING) {
         if (ch->using_rdma_cm)
             ret = rdma_accept(rdma_cm_id, &rep_param->rdma_cm);
         else
             ret = ib_send_cm_rep(ib_cm_id, &rep_param->ib_cm);
     } else {
         ret = -EINVAL;
     }
     mutex_unlock(&sport->mutex);
 
     switch (ret) {
     case 0:
         break;
     case -EINVAL:
         goto reject;
     default:
         rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
         pr_err("sending SRP_LOGIN_REQ response failed (error code = %d)\n",
                ret);
         goto reject;
     }
 
     goto out;
 
 destroy_ib:
     srpt_destroy_ch_ib(ch);
 
 free_recv_ring:
     srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_recv_ring,
                  ch->sport->sdev, ch->rq_size,
                  ch->req_buf_cache, DMA_FROM_DEVICE);
 
 free_recv_cache:
     kmem_cache_destroy(ch->req_buf_cache);
 
 free_rsp_ring:
     srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
                  ch->sport->sdev, ch->rq_size,
                  ch->rsp_buf_cache, DMA_TO_DEVICE);
 
 free_rsp_cache:
     kmem_cache_destroy(ch->rsp_buf_cache);
 
 free_ch:
     if (rdma_cm_id)
         rdma_cm_id->context = NULL;
     else
         ib_cm_id->context = NULL;
     kfree(ch);
     ch = NULL;
 
     WARN_ON_ONCE(ret == 0);
 
 reject:
     pr_info("Rejecting login with reason %#x\n", be32_to_cpu(rej->reason));
     rej->opcode = SRP_LOGIN_REJ;
     rej->tag = req->tag;
     rej->buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT |
                    SRP_BUF_FORMAT_INDIRECT);
 
     if (rdma_cm_id)
         rdma_reject(rdma_cm_id, rej, sizeof(*rej),
                 IB_CM_REJ_CONSUMER_DEFINED);
     else
         ib_send_cm_rej(ib_cm_id, IB_CM_REJ_CONSUMER_DEFINED, NULL, 0,
                    rej, sizeof(*rej));
 
     if (ch && ch->sess) {
         srpt_close_ch(ch);
         /*
          * Tell the caller not to free cm_id since
          * srpt_release_channel_work() will do that.
          */
         ret = 0;
     }
 
 out:
     kfree(rep_param);
     kfree(rsp);
     kfree(rej);
 
     return ret;
 }
 
 static int srpt_ib_cm_req_recv(struct ib_cm_id *cm_id,
                    const struct ib_cm_req_event_param *param,
                    void *private_data)
 {
     char sguid[40];
 
     srpt_format_guid(sguid, sizeof(sguid),
              &param->primary_path->dgid.global.interface_id);
 
     return srpt_cm_req_recv(cm_id->context, cm_id, NULL, param->port,
                 param->primary_path->pkey,
                 private_data, sguid);
 }
 
 static int srpt_rdma_cm_req_recv(struct rdma_cm_id *cm_id,
                  struct rdma_cm_event *event)
 {
     struct srpt_device *sdev;
     struct srp_login_req req;
     const struct srp_login_req_rdma *req_rdma;
     struct sa_path_rec *path_rec = cm_id->route.path_rec;
     char src_addr[40];
 
     sdev = ib_get_client_data(cm_id->device, &srpt_client);
     if (!sdev)
         return -ECONNREFUSED;
 
     if (event->param.conn.private_data_len < sizeof(*req_rdma))
         return -EINVAL;
 
     /* Transform srp_login_req_rdma into srp_login_req. */
     req_rdma = event->param.conn.private_data;
     memset(&req, 0, sizeof(req));
     req.opcode      = req_rdma->opcode;
     req.tag         = req_rdma->tag;
     req.req_it_iu_len   = req_rdma->req_it_iu_len;
     req.req_buf_fmt     = req_rdma->req_buf_fmt;
     req.req_flags       = req_rdma->req_flags;
     memcpy(req.initiator_port_id, req_rdma->initiator_port_id, 16);
     memcpy(req.target_port_id, req_rdma->target_port_id, 16);
     req.imm_data_offset = req_rdma->imm_data_offset;
 
     snprintf(src_addr, sizeof(src_addr), "%pIS",
          &cm_id->route.addr.src_addr);
 
     return srpt_cm_req_recv(sdev, NULL, cm_id, cm_id->port_num,
                 path_rec ? path_rec->pkey : 0, &req, src_addr);
 }
 
 static void srpt_cm_rej_recv(struct srpt_rdma_ch *ch,
                  enum ib_cm_rej_reason reason,
                  const u8 *private_data,
                  u8 private_data_len)
 {
     char *priv = NULL;
     int i;
 
     if (private_data_len && (priv = kmalloc(private_data_len * 3 + 1,
                         GFP_KERNEL))) {
         for (i = 0; i < private_data_len; i++)
             sprintf(priv + 3 * i, " %02x", private_data[i]);
     }
     pr_info("Received CM REJ for ch %s-%d; reason %d%s%s.\n",
         ch->sess_name, ch->qp->qp_num, reason, private_data_len ?
         "; private data" : "", priv ? priv : " (?)");
     kfree(priv);
 }
 
 /**
  * srpt_cm_rtu_recv - process an IB_CM_RTU_RECEIVED or USER_ESTABLISHED event
  * @ch: SRPT RDMA channel.
  *
  * An RTU (ready to use) message indicates that the connection has been
  * established and that the recipient may begin transmitting.
  */
 static void srpt_cm_rtu_recv(struct srpt_rdma_ch *ch)
 {
     int ret;
 
     ret = ch->using_rdma_cm ? 0 : srpt_ch_qp_rts(ch, ch->qp);
     if (ret < 0) {
         pr_err("%s-%d: QP transition to RTS failed\n", ch->sess_name,
                ch->qp->qp_num);
         srpt_close_ch(ch);
         return;
     }
 
     /*
      * Note: calling srpt_close_ch() if the transition to the LIVE state
      * fails is not necessary since that means that that function has
      * already been invoked from another thread.
      */
     if (!srpt_set_ch_state(ch, CH_LIVE)) {
         pr_err("%s-%d: channel transition to LIVE state failed\n",
                ch->sess_name, ch->qp->qp_num);
         return;
     }
 
     /* Trigger wait list processing. */
     ret = srpt_zerolength_write(ch);
     WARN_ONCE(ret < 0, "%d\n", ret);
 }
 
 /**
  * srpt_cm_handler - IB connection manager callback function
  * @cm_id: IB/CM connection identifier.
  * @event: IB/CM event.
  *
  * A non-zero return value will cause the caller destroy the CM ID.
  *
  * Note: srpt_cm_handler() must only return a non-zero value when transferring
  * ownership of the cm_id to a channel by srpt_cm_req_recv() failed. Returning
  * a non-zero value in any other case will trigger a race with the
  * ib_destroy_cm_id() call in srpt_release_channel().
  */
 static int srpt_cm_handler(struct ib_cm_id *cm_id,
                const struct ib_cm_event *event)
 {
     struct srpt_rdma_ch *ch = cm_id->context;
     int ret;
 
     ret = 0;
     switch (event->event) {
     case IB_CM_REQ_RECEIVED:
         ret = srpt_ib_cm_req_recv(cm_id, &event->param.req_rcvd,
                       event->private_data);
         break;
     case IB_CM_REJ_RECEIVED:
         srpt_cm_rej_recv(ch, event->param.rej_rcvd.reason,
                  event->private_data,
                  IB_CM_REJ_PRIVATE_DATA_SIZE);
         break;
     case IB_CM_RTU_RECEIVED:
     case IB_CM_USER_ESTABLISHED:
         srpt_cm_rtu_recv(ch);
         break;
     case IB_CM_DREQ_RECEIVED:
         srpt_disconnect_ch(ch);
         break;
     case IB_CM_DREP_RECEIVED:
         pr_info("Received CM DREP message for ch %s-%d.\n",
             ch->sess_name, ch->qp->qp_num);
         srpt_close_ch(ch);
         break;
     case IB_CM_TIMEWAIT_EXIT:
         pr_info("Received CM TimeWait exit for ch %s-%d.\n",
             ch->sess_name, ch->qp->qp_num);
         srpt_close_ch(ch);
         break;
     case IB_CM_REP_ERROR:
         pr_info("Received CM REP error for ch %s-%d.\n", ch->sess_name,
             ch->qp->qp_num);
         break;
     case IB_CM_DREQ_ERROR:
         pr_info("Received CM DREQ ERROR event.\n");
         break;
     case IB_CM_MRA_RECEIVED:
         pr_info("Received CM MRA event\n");
         break;
     default:
         pr_err("received unrecognized CM event %d\n", event->event);
         break;
     }
 
     return ret;
 }
 
 static int srpt_rdma_cm_handler(struct rdma_cm_id *cm_id,
                 struct rdma_cm_event *event)
 {
     struct srpt_rdma_ch *ch = cm_id->context;
     int ret = 0;
 
     switch (event->event) {
     case RDMA_CM_EVENT_CONNECT_REQUEST:
         ret = srpt_rdma_cm_req_recv(cm_id, event);
         break;
     case RDMA_CM_EVENT_REJECTED:
         srpt_cm_rej_recv(ch, event->status,
                  event->param.conn.private_data,
                  event->param.conn.private_data_len);
         break;
     case RDMA_CM_EVENT_ESTABLISHED:
         srpt_cm_rtu_recv(ch);
         break;
     case RDMA_CM_EVENT_DISCONNECTED:
         if (ch->state < CH_DISCONNECTING)
             srpt_disconnect_ch(ch);
         else
             srpt_close_ch(ch);
         break;
     case RDMA_CM_EVENT_TIMEWAIT_EXIT:
         srpt_close_ch(ch);
         break;
     case RDMA_CM_EVENT_UNREACHABLE:
         pr_info("Received CM REP error for ch %s-%d.\n", ch->sess_name,
             ch->qp->qp_num);
         break;
     case RDMA_CM_EVENT_DEVICE_REMOVAL:
     case RDMA_CM_EVENT_ADDR_CHANGE:
         break;
     default:
         pr_err("received unrecognized RDMA CM event %d\n",
                event->event);
         break;
     }
 
     return ret;
 }
 
 /*
  * srpt_write_pending - Start data transfer from initiator to target (write).
  */
 static int srpt_write_pending(struct se_cmd *se_cmd)
 {
     struct srpt_send_ioctx *ioctx =
         container_of(se_cmd, struct srpt_send_ioctx, cmd);
     struct srpt_rdma_ch *ch = ioctx->ch;
     struct ib_send_wr *first_wr = NULL;
     struct ib_cqe *cqe = &ioctx->rdma_cqe;
     enum srpt_command_state new_state;
     int ret, i;
 
     if (ioctx->recv_ioctx) {
         srpt_set_cmd_state(ioctx, SRPT_STATE_DATA_IN);
         target_execute_cmd(&ioctx->cmd);
         return 0;
     }
 
     new_state = srpt_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA);
     WARN_ON(new_state == SRPT_STATE_DONE);
 
     if (atomic_sub_return(ioctx->n_rdma, &ch->sq_wr_avail) < 0) {
         pr_warn("%s: IB send queue full (needed %d)\n",
                 __func__, ioctx->n_rdma);
         ret = -ENOMEM;
         goto out_undo;
     }
 
     cqe->done = srpt_rdma_read_done;
     for (i = ioctx->n_rw_ctx - 1; i >= 0; i--) {
         struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
 
         first_wr = rdma_rw_ctx_wrs(&ctx->rw, ch->qp, ch->sport->port,
                 cqe, first_wr);
         cqe = NULL;
     }
 
     ret = ib_post_send(ch->qp, first_wr, NULL);
     if (ret) {
         pr_err("%s: ib_post_send() returned %d for %d (avail: %d)\n",
              __func__, ret, ioctx->n_rdma,
              atomic_read(&ch->sq_wr_avail));
         goto out_undo;
     }
 
     return 0;
 out_undo:
     atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
     return ret;
 }
 
 static u8 tcm_to_srp_tsk_mgmt_status(const int tcm_mgmt_status)
 {
     switch (tcm_mgmt_status) {
     case TMR_FUNCTION_COMPLETE:
         return SRP_TSK_MGMT_SUCCESS;
     case TMR_FUNCTION_REJECTED:
         return SRP_TSK_MGMT_FUNC_NOT_SUPP;
     }
     return SRP_TSK_MGMT_FAILED;
 }
 
 /**
  * srpt_queue_response - transmit the response to a SCSI command
  * @cmd: SCSI target command.
  *
  * Callback function called by the TCM core. Must not block since it can be
  * invoked on the context of the IB completion handler.
  */
 static void srpt_queue_response(struct se_cmd *cmd)
 {
     struct srpt_send_ioctx *ioctx =
         container_of(cmd, struct srpt_send_ioctx, cmd);
     struct srpt_rdma_ch *ch = ioctx->ch;
     struct srpt_device *sdev = ch->sport->sdev;
     struct ib_send_wr send_wr, *first_wr = &send_wr;
     struct ib_sge sge;
     enum srpt_command_state state;
     int resp_len, ret, i;
     u8 srp_tm_status;
 
     state = ioctx->state;
     switch (state) {
     case SRPT_STATE_NEW:
     case SRPT_STATE_DATA_IN:
         ioctx->state = SRPT_STATE_CMD_RSP_SENT;
         break;
     case SRPT_STATE_MGMT:
         ioctx->state = SRPT_STATE_MGMT_RSP_SENT;
         break;
     default:
         WARN(true, "ch %p; cmd %d: unexpected command state %d\n",
             ch, ioctx->ioctx.index, ioctx->state);
         break;
     }
 
     if (WARN_ON_ONCE(state == SRPT_STATE_CMD_RSP_SENT))
         return;
 
     /* For read commands, transfer the data to the initiator. */
     if (ioctx->cmd.data_direction == DMA_FROM_DEVICE &&
         ioctx->cmd.data_length &&
         !ioctx->queue_status_only) {
         for (i = ioctx->n_rw_ctx - 1; i >= 0; i--) {
             struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
 
             first_wr = rdma_rw_ctx_wrs(&ctx->rw, ch->qp,
                     ch->sport->port, NULL, first_wr);
         }
     }
 
     if (state != SRPT_STATE_MGMT)
         resp_len = srpt_build_cmd_rsp(ch, ioctx, ioctx->cmd.tag,
                           cmd->scsi_status);
     else {
         srp_tm_status
             = tcm_to_srp_tsk_mgmt_status(cmd->se_tmr_req->response);
         resp_len = srpt_build_tskmgmt_rsp(ch, ioctx, srp_tm_status,
                          ioctx->cmd.tag);
     }
 
     atomic_inc(&ch->req_lim);
 
     if (unlikely(atomic_sub_return(1 + ioctx->n_rdma,
             &ch->sq_wr_avail) < 0)) {
         pr_warn("%s: IB send queue full (needed %d)\n",
                 __func__, ioctx->n_rdma);
         goto out;
     }
 
     ib_dma_sync_single_for_device(sdev->device, ioctx->ioctx.dma, resp_len,
                       DMA_TO_DEVICE);
 
     sge.addr = ioctx->ioctx.dma;
     sge.length = resp_len;
     sge.lkey = sdev->lkey;
 
     ioctx->ioctx.cqe.done = srpt_send_done;
     send_wr.next = NULL;
     send_wr.wr_cqe = &ioctx->ioctx.cqe;
     send_wr.sg_list = &sge;
     send_wr.num_sge = 1;
     send_wr.opcode = IB_WR_SEND;
     send_wr.send_flags = IB_SEND_SIGNALED;
 
     ret = ib_post_send(ch->qp, first_wr, NULL);
     if (ret < 0) {
         pr_err("%s: sending cmd response failed for tag %llu (%d)\n",
             __func__, ioctx->cmd.tag, ret);
         goto out;
     }
 
     return;
 
 out:
     atomic_add(1 + ioctx->n_rdma, &ch->sq_wr_avail);
     atomic_dec(&ch->req_lim);
     srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
     target_put_sess_cmd(&ioctx->cmd);
 }
 
 static int srpt_queue_data_in(struct se_cmd *cmd)
 {
     srpt_queue_response(cmd);
     return 0;
 }
 
 static void srpt_queue_tm_rsp(struct se_cmd *cmd)
 {
     srpt_queue_response(cmd);
 }
 
 /*
  * This function is called for aborted commands if no response is sent to the
  * initiator. Make sure that the credits freed by aborting a command are
  * returned to the initiator the next time a response is sent by incrementing
  * ch->req_lim_delta.
  */
 static void srpt_aborted_task(struct se_cmd *cmd)
 {
     struct srpt_send_ioctx *ioctx = container_of(cmd,
                 struct srpt_send_ioctx, cmd);
     struct srpt_rdma_ch *ch = ioctx->ch;
 
     atomic_inc(&ch->req_lim_delta);
 }
 
 static int srpt_queue_status(struct se_cmd *cmd)
 {
     struct srpt_send_ioctx *ioctx;
 
     ioctx = container_of(cmd, struct srpt_send_ioctx, cmd);
     BUG_ON(ioctx->sense_data != cmd->sense_buffer);
     if (cmd->se_cmd_flags &
         (SCF_TRANSPORT_TASK_SENSE | SCF_EMULATED_TASK_SENSE))
         WARN_ON(cmd->scsi_status != SAM_STAT_CHECK_CONDITION);
     ioctx->queue_status_only = true;
     srpt_queue_response(cmd);
     return 0;
 }
 
 static void srpt_refresh_port_work(struct work_struct *work)
 {
     struct srpt_port *sport = container_of(work, struct srpt_port, work);
 
     srpt_refresh_port(sport);
 }
 
 /**
  * srpt_release_sport - disable login and wait for associated channels
  * @sport: SRPT HCA port.
  */
 static int srpt_release_sport(struct srpt_port *sport)
 {
     DECLARE_COMPLETION_ONSTACK(c);
     struct srpt_nexus *nexus, *next_n;
     struct srpt_rdma_ch *ch;
 
     WARN_ON_ONCE(irqs_disabled());
 
     sport->freed_channels = &c;
 
     mutex_lock(&sport->mutex);
     srpt_set_enabled(sport, false);
     mutex_unlock(&sport->mutex);
 
     while (atomic_read(&sport->refcount) > 0 &&
            wait_for_completion_timeout(&c, 5 * HZ) <= 0) {
         pr_info("%s_%d: waiting for unregistration of %d sessions ...\n",
             dev_name(&sport->sdev->device->dev), sport->port,
             atomic_read(&sport->refcount));
         rcu_read_lock();
         list_for_each_entry(nexus, &sport->nexus_list, entry) {
             list_for_each_entry(ch, &nexus->ch_list, list) {
                 pr_info("%s-%d: state %s\n",
                     ch->sess_name, ch->qp->qp_num,
                     get_ch_state_name(ch->state));
             }
         }
         rcu_read_unlock();
     }
 
     mutex_lock(&sport->mutex);
     list_for_each_entry_safe(nexus, next_n, &sport->nexus_list, entry) {
         list_del(&nexus->entry);
         kfree_rcu(nexus, rcu);
     }
     mutex_unlock(&sport->mutex);
 
     return 0;
 }
 
 struct port_and_port_id {
     struct srpt_port *sport;
     struct srpt_port_id **port_id;
 };
 
 static struct port_and_port_id __srpt_lookup_port(const char *name)
 {
     struct ib_device *dev;
     struct srpt_device *sdev;
     struct srpt_port *sport;
     int i;
 
     list_for_each_entry(sdev, &srpt_dev_list, list) {
         dev = sdev->device;
         if (!dev)
             continue;
 
         for (i = 0; i < dev->phys_port_cnt; i++) {
             sport = &sdev->port[i];
 
             if (strcmp(sport->guid_name, name) == 0) {
                 kref_get(&sdev->refcnt);
                 return (struct port_and_port_id){
                     sport, &sport->guid_id};
             }
             if (strcmp(sport->gid_name, name) == 0) {
                 kref_get(&sdev->refcnt);
                 return (struct port_and_port_id){
                     sport, &sport->gid_id};
             }
         }
     }
 
     return (struct port_and_port_id){};
 }
 
 /**
  * srpt_lookup_port() - Look up an RDMA port by name
  * @name: ASCII port name
  *
  * Increments the RDMA port reference count if an RDMA port pointer is returned.
  * The caller must drop that reference count by calling srpt_port_put_ref().
  */
 static struct port_and_port_id srpt_lookup_port(const char *name)
 {
     struct port_and_port_id papi;
 
     spin_lock(&srpt_dev_lock);
     papi = __srpt_lookup_port(name);
     spin_unlock(&srpt_dev_lock);
 
     return papi;
 }
 
 static void srpt_free_srq(struct srpt_device *sdev)
 {
     if (!sdev->srq)
         return;
 
     ib_destroy_srq(sdev->srq);
     srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
                  sdev->srq_size, sdev->req_buf_cache,
                  DMA_FROM_DEVICE);
     kmem_cache_destroy(sdev->req_buf_cache);
     sdev->srq = NULL;
 }
 
 static int srpt_alloc_srq(struct srpt_device *sdev)
 {
     struct ib_srq_init_attr srq_attr = {
         .event_handler = srpt_srq_event,
         .srq_context = (void *)sdev,
         .attr.max_wr = sdev->srq_size,
         .attr.max_sge = 1,
         .srq_type = IB_SRQT_BASIC,
     };
     struct ib_device *device = sdev->device;
     struct ib_srq *srq;
     int i;
 
     WARN_ON_ONCE(sdev->srq);
     srq = ib_create_srq(sdev->pd, &srq_attr);
     if (IS_ERR(srq)) {
         pr_debug("ib_create_srq() failed: %ld\n", PTR_ERR(srq));
         return PTR_ERR(srq);
     }
 
     pr_debug("create SRQ #wr= %d max_allow=%d dev= %s\n", sdev->srq_size,
          sdev->device->attrs.max_srq_wr, dev_name(&device->dev));
 
     sdev->req_buf_cache = kmem_cache_create("srpt-srq-req-buf",
                         srp_max_req_size, 0, 0, NULL);
     if (!sdev->req_buf_cache)
         goto free_srq;
 
     sdev->ioctx_ring = (struct srpt_recv_ioctx **)
         srpt_alloc_ioctx_ring(sdev, sdev->srq_size,
                       sizeof(*sdev->ioctx_ring[0]),
                       sdev->req_buf_cache, 0, DMA_FROM_DEVICE);
     if (!sdev->ioctx_ring)
         goto free_cache;
 
     sdev->use_srq = true;
     sdev->srq = srq;
 
     for (i = 0; i < sdev->srq_size; ++i) {
         INIT_LIST_HEAD(&sdev->ioctx_ring[i]->wait_list);
         srpt_post_recv(sdev, NULL, sdev->ioctx_ring[i]);
     }
 
     return 0;
 
 free_cache:
     kmem_cache_destroy(sdev->req_buf_cache);
 
 free_srq:
     ib_destroy_srq(srq);
     return -ENOMEM;
 }
 
 static int srpt_use_srq(struct srpt_device *sdev, bool use_srq)
 {
     struct ib_device *device = sdev->device;
     int ret = 0;
 
     if (!use_srq) {
         srpt_free_srq(sdev);
         sdev->use_srq = false;
     } else if (use_srq && !sdev->srq) {
         ret = srpt_alloc_srq(sdev);
     }
     pr_debug("%s(%s): use_srq = %d; ret = %d\n", __func__,
          dev_name(&device->dev), sdev->use_srq, ret);
     return ret;
 }
 
 static void srpt_free_sdev(struct kref *refcnt)
 {
     struct srpt_device *sdev = container_of(refcnt, typeof(*sdev), refcnt);
 
     kfree(sdev);
 }
 
 static void srpt_sdev_put(struct srpt_device *sdev)
 {
     kref_put(&sdev->refcnt, srpt_free_sdev);
 }
 
 /**
  * srpt_add_one - InfiniBand device addition callback function
  * @device: Describes a HCA.
  */
 static int srpt_add_one(struct ib_device *device)
 {
     struct srpt_device *sdev;
     struct srpt_port *sport;
     int ret;
     u32 i;
 
     pr_debug("device = %p\n", device);
 
     sdev = kzalloc(struct_size(sdev, port, device->phys_port_cnt),
                GFP_KERNEL);
     if (!sdev)
         return -ENOMEM;
 
     kref_init(&sdev->refcnt);
     sdev->device = device;
     mutex_init(&sdev->sdev_mutex);
 
     sdev->pd = ib_alloc_pd(device, 0);
     if (IS_ERR(sdev->pd)) {
         ret = PTR_ERR(sdev->pd);
         goto free_dev;
     }
 
     sdev->lkey = sdev->pd->local_dma_lkey;
 
     sdev->srq_size = min(srpt_srq_size, sdev->device->attrs.max_srq_wr);
 
     srpt_use_srq(sdev, sdev->port[0].port_attrib.use_srq);
 
     if (!srpt_service_guid)
         srpt_service_guid = be64_to_cpu(device->node_guid);
 
     if (rdma_port_get_link_layer(device, 1) == IB_LINK_LAYER_INFINIBAND)
         sdev->cm_id = ib_create_cm_id(device, srpt_cm_handler, sdev);
     if (IS_ERR(sdev->cm_id)) {
         pr_info("ib_create_cm_id() failed: %ld\n",
             PTR_ERR(sdev->cm_id));
         ret = PTR_ERR(sdev->cm_id);
         sdev->cm_id = NULL;
         if (!rdma_cm_id)
             goto err_ring;
     }
 
     /* print out target login information */
     pr_debug("Target login info: id_ext=%016llx,ioc_guid=%016llx,pkey=ffff,service_id=%016llx\n",
          srpt_service_guid, srpt_service_guid, srpt_service_guid);
 
     /*
      * We do not have a consistent service_id (ie. also id_ext of target_id)
      * to identify this target. We currently use the guid of the first HCA
      * in the system as service_id; therefore, the target_id will change
      * if this HCA is gone bad and replaced by different HCA
      */
     ret = sdev->cm_id ?
         ib_cm_listen(sdev->cm_id, cpu_to_be64(srpt_service_guid), 0) :
         0;
     if (ret < 0) {
         pr_err("ib_cm_listen() failed: %d (cm_id state = %d)\n", ret,
                sdev->cm_id->state);
         goto err_cm;
     }
 
     INIT_IB_EVENT_HANDLER(&sdev->event_handler, sdev->device,
                   srpt_event_handler);
     ib_register_event_handler(&sdev->event_handler);
 
     for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
         sport = &sdev->port[i - 1];
         INIT_LIST_HEAD(&sport->nexus_list);
         mutex_init(&sport->mutex);
         sport->sdev = sdev;
         sport->port = i;
         sport->port_attrib.srp_max_rdma_size = DEFAULT_MAX_RDMA_SIZE;
         sport->port_attrib.srp_max_rsp_size = DEFAULT_MAX_RSP_SIZE;
         sport->port_attrib.srp_sq_size = DEF_SRPT_SQ_SIZE;
         sport->port_attrib.use_srq = false;
         INIT_WORK(&sport->work, srpt_refresh_port_work);
 
         ret = srpt_refresh_port(sport);
         if (ret) {
             pr_err("MAD registration failed for %s-%d.\n",
                    dev_name(&sdev->device->dev), i);
             i--;
             goto err_port;
         }
     }
 
     spin_lock(&srpt_dev_lock);
     list_add_tail(&sdev->list, &srpt_dev_list);
     spin_unlock(&srpt_dev_lock);
 
     ib_set_client_data(device, &srpt_client, sdev);
     pr_debug("added %s.\n", dev_name(&device->dev));
     return 0;
 
 err_port:
     srpt_unregister_mad_agent(sdev, i);
     ib_unregister_event_handler(&sdev->event_handler);
 err_cm:
     if (sdev->cm_id)
         ib_destroy_cm_id(sdev->cm_id);
 err_ring:
     srpt_free_srq(sdev);
     ib_dealloc_pd(sdev->pd);
 free_dev:
     srpt_sdev_put(sdev);
     pr_info("%s(%s) failed.\n", __func__, dev_name(&device->dev));
     return ret;
 }
 
 /**
  * srpt_remove_one - InfiniBand device removal callback function
  * @device: Describes a HCA.
  * @client_data: The value passed as the third argument to ib_set_client_data().
  */
 static void srpt_remove_one(struct ib_device *device, void *client_data)
 {
     struct srpt_device *sdev = client_data;
     int i;
 
     srpt_unregister_mad_agent(sdev, sdev->device->phys_port_cnt);
 
     ib_unregister_event_handler(&sdev->event_handler);
 
     /* Cancel any work queued by the just unregistered IB event handler. */
     for (i = 0; i < sdev->device->phys_port_cnt; i++)
         cancel_work_sync(&sdev->port[i].work);
 
     if (sdev->cm_id)
         ib_destroy_cm_id(sdev->cm_id);
 
     ib_set_client_data(device, &srpt_client, NULL);
 
     /*
      * Unregistering a target must happen after destroying sdev->cm_id
      * such that no new SRP_LOGIN_REQ information units can arrive while
      * destroying the target.
      */
     spin_lock(&srpt_dev_lock);
     list_del(&sdev->list);
     spin_unlock(&srpt_dev_lock);
 
     for (i = 0; i < sdev->device->phys_port_cnt; i++)
         srpt_release_sport(&sdev->port[i]);
 
     srpt_free_srq(sdev);
 
     ib_dealloc_pd(sdev->pd);
 
     srpt_sdev_put(sdev);
 }
 
 static struct ib_client srpt_client = {
     .name = DRV_NAME,
     .add = srpt_add_one,
     .remove = srpt_remove_one
 };
 
 static int srpt_check_true(struct se_portal_group *se_tpg)
 {
     return 1;
 }
 
 static int srpt_check_false(struct se_portal_group *se_tpg)
 {
     return 0;
 }
 
 static struct srpt_port *srpt_tpg_to_sport(struct se_portal_group *tpg)
 {
     return tpg->se_tpg_wwn->priv;
 }
 
 static struct srpt_port_id *srpt_wwn_to_sport_id(struct se_wwn *wwn)
 {
     struct srpt_port *sport = wwn->priv;
 
     if (sport->guid_id && &sport->guid_id->wwn == wwn)
         return sport->guid_id;
     if (sport->gid_id && &sport->gid_id->wwn == wwn)
         return sport->gid_id;
     WARN_ON_ONCE(true);
     return NULL;
 }
 
 static char *srpt_get_fabric_wwn(struct se_portal_group *tpg)
 {
     struct srpt_tpg *stpg = container_of(tpg, typeof(*stpg), tpg);
 
     return stpg->sport_id->name;
 }
 
 static u16 srpt_get_tag(struct se_portal_group *tpg)
 {
     return 1;
 }
 
 static u32 srpt_tpg_get_inst_index(struct se_portal_group *se_tpg)
 {
     return 1;
 }
 
 static void srpt_release_cmd(struct se_cmd *se_cmd)
 {
     struct srpt_send_ioctx *ioctx = container_of(se_cmd,
                 struct srpt_send_ioctx, cmd);
     struct srpt_rdma_ch *ch = ioctx->ch;
     struct srpt_recv_ioctx *recv_ioctx = ioctx->recv_ioctx;
 
     WARN_ON_ONCE(ioctx->state != SRPT_STATE_DONE &&
              !(ioctx->cmd.transport_state & CMD_T_ABORTED));
 
     if (recv_ioctx) {
         WARN_ON_ONCE(!list_empty(&recv_ioctx->wait_list));
         ioctx->recv_ioctx = NULL;
         srpt_post_recv(ch->sport->sdev, ch, recv_ioctx);
     }
 
     if (ioctx->n_rw_ctx) {
         srpt_free_rw_ctxs(ch, ioctx);
         ioctx->n_rw_ctx = 0;
     }
 
     target_free_tag(se_cmd->se_sess, se_cmd);
 }
 
 /**
  * srpt_close_session - forcibly close a session
  * @se_sess: SCSI target session.
  *
  * Callback function invoked by the TCM core to clean up sessions associated
  * with a node ACL when the user invokes
  * rmdir /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
  */
 static void srpt_close_session(struct se_session *se_sess)
 {
     struct srpt_rdma_ch *ch = se_sess->fabric_sess_ptr;
 
     srpt_disconnect_ch_sync(ch);
 }
 
 /**
  * srpt_sess_get_index - return the value of scsiAttIntrPortIndex (SCSI-MIB)
  * @se_sess: SCSI target session.
  *
  * A quote from RFC 4455 (SCSI-MIB) about this MIB object:
  * This object represents an arbitrary integer used to uniquely identify a
  * particular attached remote initiator port to a particular SCSI target port
  * within a particular SCSI target device within a particular SCSI instance.
  */
 static u32 srpt_sess_get_index(struct se_session *se_sess)
 {
     return 0;
 }
 
 static void srpt_set_default_node_attrs(struct se_node_acl *nacl)
 {
 }
 
 /* Note: only used from inside debug printk's by the TCM core. */
 static int srpt_get_tcm_cmd_state(struct se_cmd *se_cmd)
 {
     struct srpt_send_ioctx *ioctx;
 
     ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);
     return ioctx->state;
 }
 
 static int srpt_parse_guid(u64 *guid, const char *name)
 {
     u16 w[4];
     int ret = -EINVAL;
 
     if (sscanf(name, "%hx:%hx:%hx:%hx", &w[0], &w[1], &w[2], &w[3]) != 4)
         goto out;
     *guid = get_unaligned_be64(w);
     ret = 0;
 out:
     return ret;
 }
 
 /**
  * srpt_parse_i_port_id - parse an initiator port ID
  * @name: ASCII representation of a 128-bit initiator port ID.
  * @i_port_id: Binary 128-bit port ID.
  */
 static int srpt_parse_i_port_id(u8 i_port_id[16], const char *name)
 {
     const char *p;
     unsigned len, count, leading_zero_bytes;
     int ret;
 
     p = name;
     if (strncasecmp(p, "0x", 2) == 0)
         p += 2;
     ret = -EINVAL;
     len = strlen(p);
     if (len % 2)
         goto out;
     count = min(len / 2, 16U);
     leading_zero_bytes = 16 - count;
     memset(i_port_id, 0, leading_zero_bytes);
     ret = hex2bin(i_port_id + leading_zero_bytes, p, count);
 
 out:
     return ret;
 }
 
 /*
  * configfs callback function invoked for mkdir
  * /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
  *
  * i_port_id must be an initiator port GUID, GID or IP address. See also the
  * target_alloc_session() calls in this driver. Examples of valid initiator
  * port IDs:
  * 0x0000000000000000505400fffe4a0b7b
  * 0000000000000000505400fffe4a0b7b
  * 5054:00ff:fe4a:0b7b
  * 192.168.122.76
  */
 static int srpt_init_nodeacl(struct se_node_acl *se_nacl, const char *name)
 {
     struct sockaddr_storage sa;
     u64 guid;
     u8 i_port_id[16];
     int ret;
 
     ret = srpt_parse_guid(&guid, name);
     if (ret < 0)
         ret = srpt_parse_i_port_id(i_port_id, name);
     if (ret < 0)
         ret = inet_pton_with_scope(&init_net, AF_UNSPEC, name, NULL,
                        &sa);
     if (ret < 0)
         pr_err("invalid initiator port ID %s\n", name);
     return ret;
 }
 
 static ssize_t srpt_tpg_attrib_srp_max_rdma_size_show(struct config_item *item,
         char *page)
 {
     struct se_portal_group *se_tpg = attrib_to_tpg(item);
     struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
 
     return sysfs_emit(page, "%u\n", sport->port_attrib.srp_max_rdma_size);
 }
 
 static ssize_t srpt_tpg_attrib_srp_max_rdma_size_store(struct config_item *item,
         const char *page, size_t count)
 {
     struct se_portal_group *se_tpg = attrib_to_tpg(item);
     struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
     unsigned long val;
     int ret;
 
     ret = kstrtoul(page, 0, &val);
     if (ret < 0) {
         pr_err("kstrtoul() failed with ret: %d\n", ret);
         return -EINVAL;
     }
     if (val > MAX_SRPT_RDMA_SIZE) {
         pr_err("val: %lu exceeds MAX_SRPT_RDMA_SIZE: %d\n", val,
             MAX_SRPT_RDMA_SIZE);
         return -EINVAL;
     }
     if (val < DEFAULT_MAX_RDMA_SIZE) {
         pr_err("val: %lu smaller than DEFAULT_MAX_RDMA_SIZE: %d\n",
             val, DEFAULT_MAX_RDMA_SIZE);
         return -EINVAL;
     }
     sport->port_attrib.srp_max_rdma_size = val;
 
     return count;
 }
 
 static ssize_t srpt_tpg_attrib_srp_max_rsp_size_show(struct config_item *item,
         char *page)
 {
     struct se_portal_group *se_tpg = attrib_to_tpg(item);
     struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
 
     return sysfs_emit(page, "%u\n", sport->port_attrib.srp_max_rsp_size);
 }
 
 static ssize_t srpt_tpg_attrib_srp_max_rsp_size_store(struct config_item *item,
         const char *page, size_t count)
 {
     struct se_portal_group *se_tpg = attrib_to_tpg(item);
     struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
     unsigned long val;
     int ret;
 
     ret = kstrtoul(page, 0, &val);
     if (ret < 0) {
         pr_err("kstrtoul() failed with ret: %d\n", ret);
         return -EINVAL;
     }
     if (val > MAX_SRPT_RSP_SIZE) {
         pr_err("val: %lu exceeds MAX_SRPT_RSP_SIZE: %d\n", val,
             MAX_SRPT_RSP_SIZE);
         return -EINVAL;
     }
     if (val < MIN_MAX_RSP_SIZE) {
         pr_err("val: %lu smaller than MIN_MAX_RSP_SIZE: %d\n", val,
             MIN_MAX_RSP_SIZE);
         return -EINVAL;
     }
     sport->port_attrib.srp_max_rsp_size = val;
 
     return count;
 }
 
 static ssize_t srpt_tpg_attrib_srp_sq_size_show(struct config_item *item,
         char *page)
 {
     struct se_portal_group *se_tpg = attrib_to_tpg(item);
     struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
 
     return sysfs_emit(page, "%u\n", sport->port_attrib.srp_sq_size);
 }
 
 static ssize_t srpt_tpg_attrib_srp_sq_size_store(struct config_item *item,
         const char *page, size_t count)
 {
     struct se_portal_group *se_tpg = attrib_to_tpg(item);
     struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
     unsigned long val;
     int ret;
 
     ret = kstrtoul(page, 0, &val);
     if (ret < 0) {
         pr_err("kstrtoul() failed with ret: %d\n", ret);
         return -EINVAL;
     }
     if (val > MAX_SRPT_SRQ_SIZE) {
         pr_err("val: %lu exceeds MAX_SRPT_SRQ_SIZE: %d\n", val,
             MAX_SRPT_SRQ_SIZE);
         return -EINVAL;
     }
     if (val < MIN_SRPT_SRQ_SIZE) {
         pr_err("val: %lu smaller than MIN_SRPT_SRQ_SIZE: %d\n", val,
             MIN_SRPT_SRQ_SIZE);
         return -EINVAL;
     }
     sport->port_attrib.srp_sq_size = val;
 
     return count;
 }
 
 static ssize_t srpt_tpg_attrib_use_srq_show(struct config_item *item,
                         char *page)
 {
     struct se_portal_group *se_tpg = attrib_to_tpg(item);
     struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
 
     return sysfs_emit(page, "%d\n", sport->port_attrib.use_srq);
 }
 
 static ssize_t srpt_tpg_attrib_use_srq_store(struct config_item *item,
                          const char *page, size_t count)
 {
     struct se_portal_group *se_tpg = attrib_to_tpg(item);
     struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
     struct srpt_device *sdev = sport->sdev;
     unsigned long val;
     bool enabled;
     int ret;
 
     ret = kstrtoul(page, 0, &val);
     if (ret < 0)
         return ret;
     if (val != !!val)
         return -EINVAL;
 
     ret = mutex_lock_interruptible(&sdev->sdev_mutex);
     if (ret < 0)
         return ret;
     ret = mutex_lock_interruptible(&sport->mutex);
     if (ret < 0)
         goto unlock_sdev;
     enabled = sport->enabled;
     /* Log out all initiator systems before changing 'use_srq'. */
     srpt_set_enabled(sport, false);
     sport->port_attrib.use_srq = val;
     srpt_use_srq(sdev, sport->port_attrib.use_srq);
     srpt_set_enabled(sport, enabled);
     ret = count;
     mutex_unlock(&sport->mutex);
 unlock_sdev:
     mutex_unlock(&sdev->sdev_mutex);
 
     return ret;
 }
 
 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_max_rdma_size);
 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_max_rsp_size);
 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_sq_size);
 CONFIGFS_ATTR(srpt_tpg_attrib_,  use_srq);
 
 static struct configfs_attribute *srpt_tpg_attrib_attrs[] = {
     &srpt_tpg_attrib_attr_srp_max_rdma_size,
     &srpt_tpg_attrib_attr_srp_max_rsp_size,
     &srpt_tpg_attrib_attr_srp_sq_size,
     &srpt_tpg_attrib_attr_use_srq,
     NULL,
 };
 
 static struct rdma_cm_id *srpt_create_rdma_id(struct sockaddr *listen_addr)
 {
     struct rdma_cm_id *rdma_cm_id;
     int ret;
 
     rdma_cm_id = rdma_create_id(&init_net, srpt_rdma_cm_handler,
                     NULL, RDMA_PS_TCP, IB_QPT_RC);
     if (IS_ERR(rdma_cm_id)) {
         pr_err("RDMA/CM ID creation failed: %ld\n",
                PTR_ERR(rdma_cm_id));
         goto out;
     }
 
     ret = rdma_bind_addr(rdma_cm_id, listen_addr);
     if (ret) {
         char addr_str[64];
 
         snprintf(addr_str, sizeof(addr_str), "%pISp", listen_addr);
         pr_err("Binding RDMA/CM ID to address %s failed: %d\n",
                addr_str, ret);
         rdma_destroy_id(rdma_cm_id);
         rdma_cm_id = ERR_PTR(ret);
         goto out;
     }
 
     ret = rdma_listen(rdma_cm_id, 128);
     if (ret) {
         pr_err("rdma_listen() failed: %d\n", ret);
         rdma_destroy_id(rdma_cm_id);
         rdma_cm_id = ERR_PTR(ret);
     }
 
 out:
     return rdma_cm_id;
 }
 
 static ssize_t srpt_rdma_cm_port_show(struct config_item *item, char *page)
 {
     return sysfs_emit(page, "%d\n", rdma_cm_port);
 }
 
 static ssize_t srpt_rdma_cm_port_store(struct config_item *item,
                        const char *page, size_t count)
 {
     struct sockaddr_in  addr4 = { .sin_family  = AF_INET  };
     struct sockaddr_in6 addr6 = { .sin6_family = AF_INET6 };
     struct rdma_cm_id *new_id = NULL;
     u16 val;
     int ret;
 
     ret = kstrtou16(page, 0, &val);
     if (ret < 0)
         return ret;
     ret = count;
     if (rdma_cm_port == val)
         goto out;
 
     if (val) {
         addr6.sin6_port = cpu_to_be16(val);
         new_id = srpt_create_rdma_id((struct sockaddr *)&addr6);
         if (IS_ERR(new_id)) {
             addr4.sin_port = cpu_to_be16(val);
             new_id = srpt_create_rdma_id((struct sockaddr *)&addr4);
             if (IS_ERR(new_id)) {
                 ret = PTR_ERR(new_id);
                 goto out;
             }
         }
     }
 
     mutex_lock(&rdma_cm_mutex);
     rdma_cm_port = val;
     swap(rdma_cm_id, new_id);
     mutex_unlock(&rdma_cm_mutex);
 
     if (new_id)
         rdma_destroy_id(new_id);
     ret = count;
 out:
     return ret;
 }
 
 CONFIGFS_ATTR(srpt_, rdma_cm_port);
 
 static struct configfs_attribute *srpt_da_attrs[] = {
     &srpt_attr_rdma_cm_port,
     NULL,
 };
 
 static int srpt_enable_tpg(struct se_portal_group *se_tpg, bool enable)
 {
     struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
 
     mutex_lock(&sport->mutex);
     srpt_set_enabled(sport, enable);
     mutex_unlock(&sport->mutex);
 
     return 0;
 }
 
 /**
  * srpt_make_tpg - configfs callback invoked for mkdir /sys/kernel/config/target/$driver/$port/$tpg
  * @wwn: Corresponds to $driver/$port.
  * @name: $tpg.
  */
 static struct se_portal_group *srpt_make_tpg(struct se_wwn *wwn,
                          const char *name)
 {
     struct srpt_port_id *sport_id = srpt_wwn_to_sport_id(wwn);
     struct srpt_tpg *stpg;
     int res = -ENOMEM;
 
     stpg = kzalloc(sizeof(*stpg), GFP_KERNEL);
     if (!stpg)
         return ERR_PTR(res);
     stpg->sport_id = sport_id;
     res = core_tpg_register(wwn, &stpg->tpg, SCSI_PROTOCOL_SRP);
     if (res) {
         kfree(stpg);
         return ERR_PTR(res);
     }
 
     mutex_lock(&sport_id->mutex);
     list_add_tail(&stpg->entry, &sport_id->tpg_list);
     mutex_unlock(&sport_id->mutex);
 
     return &stpg->tpg;
 }
 
 /**
  * srpt_drop_tpg - configfs callback invoked for rmdir /sys/kernel/config/target/$driver/$port/$tpg
  * @tpg: Target portal group to deregister.
  */
 static void srpt_drop_tpg(struct se_portal_group *tpg)
 {
     struct srpt_tpg *stpg = container_of(tpg, typeof(*stpg), tpg);
     struct srpt_port_id *sport_id = stpg->sport_id;
     struct srpt_port *sport = srpt_tpg_to_sport(tpg);
 
     mutex_lock(&sport_id->mutex);
     list_del(&stpg->entry);
     mutex_unlock(&sport_id->mutex);
 
     sport->enabled = false;
     core_tpg_deregister(tpg);
     kfree(stpg);
 }
 
 /**
  * srpt_make_tport - configfs callback invoked for mkdir /sys/kernel/config/target/$driver/$port
  * @tf: Not used.
  * @group: Not used.
  * @name: $port.
  */
 static struct se_wwn *srpt_make_tport(struct target_fabric_configfs *tf,
                       struct config_group *group,
                       const char *name)
 {
     struct port_and_port_id papi = srpt_lookup_port(name);
     struct srpt_port *sport = papi.sport;
     struct srpt_port_id *port_id;
 
     if (!papi.port_id)
         return ERR_PTR(-EINVAL);
     if (*papi.port_id) {
         /* Attempt to create a directory that already exists. */
         WARN_ON_ONCE(true);
         return &(*papi.port_id)->wwn;
     }
     port_id = kzalloc(sizeof(*port_id), GFP_KERNEL);
     if (!port_id) {
         srpt_sdev_put(sport->sdev);
         return ERR_PTR(-ENOMEM);
     }
     mutex_init(&port_id->mutex);
     INIT_LIST_HEAD(&port_id->tpg_list);
     port_id->wwn.priv = sport;
     memcpy(port_id->name, port_id == sport->guid_id ? sport->guid_name :
            sport->gid_name, ARRAY_SIZE(port_id->name));
 
     *papi.port_id = port_id;
 
     return &port_id->wwn;
 }
 
 /**
  * srpt_drop_tport - configfs callback invoked for rmdir /sys/kernel/config/target/$driver/$port
  * @wwn: $port.
  */
 static void srpt_drop_tport(struct se_wwn *wwn)
 {
     struct srpt_port_id *port_id = container_of(wwn, typeof(*port_id), wwn);
     struct srpt_port *sport = wwn->priv;
 
     if (sport->guid_id == port_id)
         sport->guid_id = NULL;
     else if (sport->gid_id == port_id)
         sport->gid_id = NULL;
     else
         WARN_ON_ONCE(true);
 
     srpt_sdev_put(sport->sdev);
     kfree(port_id);
 }
 
 static ssize_t srpt_wwn_version_show(struct config_item *item, char *buf)
 {
     return sysfs_emit(buf, "\n");
 }
 
 CONFIGFS_ATTR_RO(srpt_wwn_, version);
 
 static struct configfs_attribute *srpt_wwn_attrs[] = {
     &srpt_wwn_attr_version,
     NULL,
 };
 
 static const struct target_core_fabric_ops srpt_template = {
     .module             = THIS_MODULE,
     .fabric_name            = "srpt",
     .tpg_get_wwn            = srpt_get_fabric_wwn,
     .tpg_get_tag            = srpt_get_tag,
     .tpg_check_demo_mode        = srpt_check_false,
     .tpg_check_demo_mode_cache  = srpt_check_true,
     .tpg_check_demo_mode_write_protect = srpt_check_true,
     .tpg_check_prod_mode_write_protect = srpt_check_false,
     .tpg_get_inst_index     = srpt_tpg_get_inst_index,
     .release_cmd            = srpt_release_cmd,
     .check_stop_free        = srpt_check_stop_free,
     .close_session          = srpt_close_session,
     .sess_get_index         = srpt_sess_get_index,
     .sess_get_initiator_sid     = NULL,
     .write_pending          = srpt_write_pending,
     .set_default_node_attributes    = srpt_set_default_node_attrs,
     .get_cmd_state          = srpt_get_tcm_cmd_state,
     .queue_data_in          = srpt_queue_data_in,
     .queue_status           = srpt_queue_status,
     .queue_tm_rsp           = srpt_queue_tm_rsp,
     .aborted_task           = srpt_aborted_task,
     /*
      * Setup function pointers for generic logic in
      * target_core_fabric_configfs.c
      */
     .fabric_make_wwn        = srpt_make_tport,
     .fabric_drop_wwn        = srpt_drop_tport,
     .fabric_make_tpg        = srpt_make_tpg,
     .fabric_enable_tpg      = srpt_enable_tpg,
     .fabric_drop_tpg        = srpt_drop_tpg,
     .fabric_init_nodeacl        = srpt_init_nodeacl,
 
     .tfc_discovery_attrs        = srpt_da_attrs,
     .tfc_wwn_attrs          = srpt_wwn_attrs,
     .tfc_tpg_attrib_attrs       = srpt_tpg_attrib_attrs,
 };
 
 /**
  * srpt_init_module - kernel module initialization
  *
  * Note: Since ib_register_client() registers callback functions, and since at
  * least one of these callback functions (srpt_add_one()) calls target core
  * functions, this driver must be registered with the target core before
  * ib_register_client() is called.
  */
 static int __init srpt_init_module(void)
 {
     int ret;
 
     ret = -EINVAL;
     if (srp_max_req_size < MIN_MAX_REQ_SIZE) {
         pr_err("invalid value %d for kernel module parameter srp_max_req_size -- must be at least %d.\n",
                srp_max_req_size, MIN_MAX_REQ_SIZE);
         goto out;
     }
 
     if (srpt_srq_size < MIN_SRPT_SRQ_SIZE
         || srpt_srq_size > MAX_SRPT_SRQ_SIZE) {
         pr_err("invalid value %d for kernel module parameter srpt_srq_size -- must be in the range [%d..%d].\n",
                srpt_srq_size, MIN_SRPT_SRQ_SIZE, MAX_SRPT_SRQ_SIZE);
         goto out;
     }
 
     ret = target_register_template(&srpt_template);
     if (ret)
         goto out;
 
     ret = ib_register_client(&srpt_client);
     if (ret) {
         pr_err("couldn't register IB client\n");
         goto out_unregister_target;
     }
 
     return 0;
 
 out_unregister_target:
     target_unregister_template(&srpt_template);
 out:
     return ret;
 }
 
 static void __exit srpt_cleanup_module(void)
 {
     if (rdma_cm_id)
         rdma_destroy_id(rdma_cm_id);
     ib_unregister_client(&srpt_client);
     target_unregister_template(&srpt_template);
 }
 
 module_init(srpt_init_module);
 module_exit(srpt_cleanup_module);