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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*******************************************************************************
  * Filename:  target_core_transport.c
  *
  * This file contains the Generic Target Engine Core.
  *
  * (c) Copyright 2002-2013 Datera, Inc.
  *
  * Nicholas A. Bellinger <nab@kernel.org>
  *
  ******************************************************************************/
 
 #include <linux/net.h>
 #include <linux/delay.h>
 #include <linux/string.h>
 #include <linux/timer.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/kthread.h>
 #include <linux/in.h>
 #include <linux/cdrom.h>
 #include <linux/module.h>
 #include <linux/ratelimit.h>
 #include <linux/vmalloc.h>
 #include <asm/unaligned.h>
 #include <net/sock.h>
 #include <net/tcp.h>
 #include <scsi/scsi_proto.h>
 #include <scsi/scsi_common.h>
 
 #include <target/target_core_base.h>
 #include <target/target_core_backend.h>
 #include <target/target_core_fabric.h>
 
 #include "target_core_internal.h"
 #include "target_core_alua.h"
 #include "target_core_pr.h"
 #include "target_core_ua.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/target.h>
 
 static struct workqueue_struct *target_completion_wq;
 static struct workqueue_struct *target_submission_wq;
 static struct kmem_cache *se_sess_cache;
 struct kmem_cache *se_ua_cache;
 struct kmem_cache *t10_pr_reg_cache;
 struct kmem_cache *t10_alua_lu_gp_cache;
 struct kmem_cache *t10_alua_lu_gp_mem_cache;
 struct kmem_cache *t10_alua_tg_pt_gp_cache;
 struct kmem_cache *t10_alua_lba_map_cache;
 struct kmem_cache *t10_alua_lba_map_mem_cache;
 
 static void transport_complete_task_attr(struct se_cmd *cmd);
 static void translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason);
 static void transport_handle_queue_full(struct se_cmd *cmd,
         struct se_device *dev, int err, bool write_pending);
 static void target_complete_ok_work(struct work_struct *work);
 
 int init_se_kmem_caches(void)
 {
     se_sess_cache = kmem_cache_create("se_sess_cache",
             sizeof(struct se_session), __alignof__(struct se_session),
             0, NULL);
     if (!se_sess_cache) {
         pr_err("kmem_cache_create() for struct se_session"
                 " failed\n");
         goto out;
     }
     se_ua_cache = kmem_cache_create("se_ua_cache",
             sizeof(struct se_ua), __alignof__(struct se_ua),
             0, NULL);
     if (!se_ua_cache) {
         pr_err("kmem_cache_create() for struct se_ua failed\n");
         goto out_free_sess_cache;
     }
     t10_pr_reg_cache = kmem_cache_create("t10_pr_reg_cache",
             sizeof(struct t10_pr_registration),
             __alignof__(struct t10_pr_registration), 0, NULL);
     if (!t10_pr_reg_cache) {
         pr_err("kmem_cache_create() for struct t10_pr_registration"
                 " failed\n");
         goto out_free_ua_cache;
     }
     t10_alua_lu_gp_cache = kmem_cache_create("t10_alua_lu_gp_cache",
             sizeof(struct t10_alua_lu_gp), __alignof__(struct t10_alua_lu_gp),
             0, NULL);
     if (!t10_alua_lu_gp_cache) {
         pr_err("kmem_cache_create() for t10_alua_lu_gp_cache"
                 " failed\n");
         goto out_free_pr_reg_cache;
     }
     t10_alua_lu_gp_mem_cache = kmem_cache_create("t10_alua_lu_gp_mem_cache",
             sizeof(struct t10_alua_lu_gp_member),
             __alignof__(struct t10_alua_lu_gp_member), 0, NULL);
     if (!t10_alua_lu_gp_mem_cache) {
         pr_err("kmem_cache_create() for t10_alua_lu_gp_mem_"
                 "cache failed\n");
         goto out_free_lu_gp_cache;
     }
     t10_alua_tg_pt_gp_cache = kmem_cache_create("t10_alua_tg_pt_gp_cache",
             sizeof(struct t10_alua_tg_pt_gp),
             __alignof__(struct t10_alua_tg_pt_gp), 0, NULL);
     if (!t10_alua_tg_pt_gp_cache) {
         pr_err("kmem_cache_create() for t10_alua_tg_pt_gp_"
                 "cache failed\n");
         goto out_free_lu_gp_mem_cache;
     }
     t10_alua_lba_map_cache = kmem_cache_create(
             "t10_alua_lba_map_cache",
             sizeof(struct t10_alua_lba_map),
             __alignof__(struct t10_alua_lba_map), 0, NULL);
     if (!t10_alua_lba_map_cache) {
         pr_err("kmem_cache_create() for t10_alua_lba_map_"
                 "cache failed\n");
         goto out_free_tg_pt_gp_cache;
     }
     t10_alua_lba_map_mem_cache = kmem_cache_create(
             "t10_alua_lba_map_mem_cache",
             sizeof(struct t10_alua_lba_map_member),
             __alignof__(struct t10_alua_lba_map_member), 0, NULL);
     if (!t10_alua_lba_map_mem_cache) {
         pr_err("kmem_cache_create() for t10_alua_lba_map_mem_"
                 "cache failed\n");
         goto out_free_lba_map_cache;
     }
 
     target_completion_wq = alloc_workqueue("target_completion",
                            WQ_MEM_RECLAIM, 0);
     if (!target_completion_wq)
         goto out_free_lba_map_mem_cache;
 
     target_submission_wq = alloc_workqueue("target_submission",
                            WQ_MEM_RECLAIM, 0);
     if (!target_submission_wq)
         goto out_free_completion_wq;
 
     return 0;
 
 out_free_completion_wq:
     destroy_workqueue(target_completion_wq);
 out_free_lba_map_mem_cache:
     kmem_cache_destroy(t10_alua_lba_map_mem_cache);
 out_free_lba_map_cache:
     kmem_cache_destroy(t10_alua_lba_map_cache);
 out_free_tg_pt_gp_cache:
     kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
 out_free_lu_gp_mem_cache:
     kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
 out_free_lu_gp_cache:
     kmem_cache_destroy(t10_alua_lu_gp_cache);
 out_free_pr_reg_cache:
     kmem_cache_destroy(t10_pr_reg_cache);
 out_free_ua_cache:
     kmem_cache_destroy(se_ua_cache);
 out_free_sess_cache:
     kmem_cache_destroy(se_sess_cache);
 out:
     return -ENOMEM;
 }
 
 void release_se_kmem_caches(void)
 {
     destroy_workqueue(target_submission_wq);
     destroy_workqueue(target_completion_wq);
     kmem_cache_destroy(se_sess_cache);
     kmem_cache_destroy(se_ua_cache);
     kmem_cache_destroy(t10_pr_reg_cache);
     kmem_cache_destroy(t10_alua_lu_gp_cache);
     kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
     kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
     kmem_cache_destroy(t10_alua_lba_map_cache);
     kmem_cache_destroy(t10_alua_lba_map_mem_cache);
 }
 
 /* This code ensures unique mib indexes are handed out. */
 static DEFINE_SPINLOCK(scsi_mib_index_lock);
 static u32 scsi_mib_index[SCSI_INDEX_TYPE_MAX];
 
 /*
  * Allocate a new row index for the entry type specified
  */
 u32 scsi_get_new_index(scsi_index_t type)
 {
     u32 new_index;
 
     BUG_ON((type < 0) || (type >= SCSI_INDEX_TYPE_MAX));
 
     spin_lock(&scsi_mib_index_lock);
     new_index = ++scsi_mib_index[type];
     spin_unlock(&scsi_mib_index_lock);
 
     return new_index;
 }
 
 void transport_subsystem_check_init(void)
 {
     int ret;
     static int sub_api_initialized;
 
     if (sub_api_initialized)
         return;
 
     ret = IS_ENABLED(CONFIG_TCM_IBLOCK) && request_module("target_core_iblock");
     if (ret != 0)
         pr_err("Unable to load target_core_iblock\n");
 
     ret = IS_ENABLED(CONFIG_TCM_FILEIO) && request_module("target_core_file");
     if (ret != 0)
         pr_err("Unable to load target_core_file\n");
 
     ret = IS_ENABLED(CONFIG_TCM_PSCSI) && request_module("target_core_pscsi");
     if (ret != 0)
         pr_err("Unable to load target_core_pscsi\n");
 
     ret = IS_ENABLED(CONFIG_TCM_USER2) && request_module("target_core_user");
     if (ret != 0)
         pr_err("Unable to load target_core_user\n");
 
     sub_api_initialized = 1;
 }
 
 static void target_release_sess_cmd_refcnt(struct percpu_ref *ref)
 {
     struct se_session *sess = container_of(ref, typeof(*sess), cmd_count);
 
     wake_up(&sess->cmd_count_wq);
 }
 
 /**
  * transport_init_session - initialize a session object
  * @se_sess: Session object pointer.
  *
  * The caller must have zero-initialized @se_sess before calling this function.
  */
 int transport_init_session(struct se_session *se_sess)
 {
     INIT_LIST_HEAD(&se_sess->sess_list);
     INIT_LIST_HEAD(&se_sess->sess_acl_list);
     spin_lock_init(&se_sess->sess_cmd_lock);
     init_waitqueue_head(&se_sess->cmd_count_wq);
     init_completion(&se_sess->stop_done);
     atomic_set(&se_sess->stopped, 0);
     return percpu_ref_init(&se_sess->cmd_count,
                    target_release_sess_cmd_refcnt, 0, GFP_KERNEL);
 }
 EXPORT_SYMBOL(transport_init_session);
 
 void transport_uninit_session(struct se_session *se_sess)
 {
     /*
      * Drivers like iscsi and loop do not call target_stop_session
      * during session shutdown so we have to drop the ref taken at init
      * time here.
      */
     if (!atomic_read(&se_sess->stopped))
         percpu_ref_put(&se_sess->cmd_count);
 
     percpu_ref_exit(&se_sess->cmd_count);
 }
 
 /**
  * transport_alloc_session - allocate a session object and initialize it
  * @sup_prot_ops: bitmask that defines which T10-PI modes are supported.
  */
 struct se_session *transport_alloc_session(enum target_prot_op sup_prot_ops)
 {
     struct se_session *se_sess;
     int ret;
 
     se_sess = kmem_cache_zalloc(se_sess_cache, GFP_KERNEL);
     if (!se_sess) {
         pr_err("Unable to allocate struct se_session from"
                 " se_sess_cache\n");
         return ERR_PTR(-ENOMEM);
     }
     ret = transport_init_session(se_sess);
     if (ret < 0) {
         kmem_cache_free(se_sess_cache, se_sess);
         return ERR_PTR(ret);
     }
     se_sess->sup_prot_ops = sup_prot_ops;
 
     return se_sess;
 }
 EXPORT_SYMBOL(transport_alloc_session);
 
 /**
  * transport_alloc_session_tags - allocate target driver private data
  * @se_sess:  Session pointer.
  * @tag_num:  Maximum number of in-flight commands between initiator and target.
  * @tag_size: Size in bytes of the private data a target driver associates with
  *        each command.
  */
 int transport_alloc_session_tags(struct se_session *se_sess,
                      unsigned int tag_num, unsigned int tag_size)
 {
     int rc;
 
     se_sess->sess_cmd_map = kvcalloc(tag_size, tag_num,
                      GFP_KERNEL | __GFP_RETRY_MAYFAIL);
     if (!se_sess->sess_cmd_map) {
         pr_err("Unable to allocate se_sess->sess_cmd_map\n");
         return -ENOMEM;
     }
 
     rc = sbitmap_queue_init_node(&se_sess->sess_tag_pool, tag_num, -1,
             false, GFP_KERNEL, NUMA_NO_NODE);
     if (rc < 0) {
         pr_err("Unable to init se_sess->sess_tag_pool,"
             " tag_num: %u\n", tag_num);
         kvfree(se_sess->sess_cmd_map);
         se_sess->sess_cmd_map = NULL;
         return -ENOMEM;
     }
 
     return 0;
 }
 EXPORT_SYMBOL(transport_alloc_session_tags);
 
 /**
  * transport_init_session_tags - allocate a session and target driver private data
  * @tag_num:  Maximum number of in-flight commands between initiator and target.
  * @tag_size: Size in bytes of the private data a target driver associates with
  *        each command.
  * @sup_prot_ops: bitmask that defines which T10-PI modes are supported.
  */
 static struct se_session *
 transport_init_session_tags(unsigned int tag_num, unsigned int tag_size,
                 enum target_prot_op sup_prot_ops)
 {
     struct se_session *se_sess;
     int rc;
 
     if (tag_num != 0 && !tag_size) {
         pr_err("init_session_tags called with percpu-ida tag_num:"
                " %u, but zero tag_size\n", tag_num);
         return ERR_PTR(-EINVAL);
     }
     if (!tag_num && tag_size) {
         pr_err("init_session_tags called with percpu-ida tag_size:"
                " %u, but zero tag_num\n", tag_size);
         return ERR_PTR(-EINVAL);
     }
 
     se_sess = transport_alloc_session(sup_prot_ops);
     if (IS_ERR(se_sess))
         return se_sess;
 
     rc = transport_alloc_session_tags(se_sess, tag_num, tag_size);
     if (rc < 0) {
         transport_free_session(se_sess);
         return ERR_PTR(-ENOMEM);
     }
 
     return se_sess;
 }
 
 /*
  * Called with spin_lock_irqsave(&struct se_portal_group->session_lock called.
  */
 void __transport_register_session(
     struct se_portal_group *se_tpg,
     struct se_node_acl *se_nacl,
     struct se_session *se_sess,
     void *fabric_sess_ptr)
 {
     const struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
     unsigned char buf[PR_REG_ISID_LEN];
     unsigned long flags;
 
     se_sess->se_tpg = se_tpg;
     se_sess->fabric_sess_ptr = fabric_sess_ptr;
     /*
      * Used by struct se_node_acl's under ConfigFS to locate active se_session-t
      *
      * Only set for struct se_session's that will actually be moving I/O.
      * eg: *NOT* discovery sessions.
      */
     if (se_nacl) {
         /*
          *
          * Determine if fabric allows for T10-PI feature bits exposed to
          * initiators for device backends with !dev->dev_attrib.pi_prot_type.
          *
          * If so, then always save prot_type on a per se_node_acl node
          * basis and re-instate the previous sess_prot_type to avoid
          * disabling PI from below any previously initiator side
          * registered LUNs.
          */
         if (se_nacl->saved_prot_type)
             se_sess->sess_prot_type = se_nacl->saved_prot_type;
         else if (tfo->tpg_check_prot_fabric_only)
             se_sess->sess_prot_type = se_nacl->saved_prot_type =
                     tfo->tpg_check_prot_fabric_only(se_tpg);
         /*
          * If the fabric module supports an ISID based TransportID,
          * save this value in binary from the fabric I_T Nexus now.
          */
         if (se_tpg->se_tpg_tfo->sess_get_initiator_sid != NULL) {
             memset(&buf[0], 0, PR_REG_ISID_LEN);
             se_tpg->se_tpg_tfo->sess_get_initiator_sid(se_sess,
                     &buf[0], PR_REG_ISID_LEN);
             se_sess->sess_bin_isid = get_unaligned_be64(&buf[0]);
         }
 
         spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
         /*
          * The se_nacl->nacl_sess pointer will be set to the
          * last active I_T Nexus for each struct se_node_acl.
          */
         se_nacl->nacl_sess = se_sess;
 
         list_add_tail(&se_sess->sess_acl_list,
                   &se_nacl->acl_sess_list);
         spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
     }
     list_add_tail(&se_sess->sess_list, &se_tpg->tpg_sess_list);
 
     pr_debug("TARGET_CORE[%s]: Registered fabric_sess_ptr: %p\n",
         se_tpg->se_tpg_tfo->fabric_name, se_sess->fabric_sess_ptr);
 }
 EXPORT_SYMBOL(__transport_register_session);
 
 void transport_register_session(
     struct se_portal_group *se_tpg,
     struct se_node_acl *se_nacl,
     struct se_session *se_sess,
     void *fabric_sess_ptr)
 {
     unsigned long flags;
 
     spin_lock_irqsave(&se_tpg->session_lock, flags);
     __transport_register_session(se_tpg, se_nacl, se_sess, fabric_sess_ptr);
     spin_unlock_irqrestore(&se_tpg->session_lock, flags);
 }
 EXPORT_SYMBOL(transport_register_session);
 
 struct se_session *
 target_setup_session(struct se_portal_group *tpg,
              unsigned int tag_num, unsigned int tag_size,
              enum target_prot_op prot_op,
              const char *initiatorname, void *private,
              int (*callback)(struct se_portal_group *,
                      struct se_session *, void *))
 {
     struct se_session *sess;
 
     /*
      * If the fabric driver is using percpu-ida based pre allocation
      * of I/O descriptor tags, go ahead and perform that setup now..
      */
     if (tag_num != 0)
         sess = transport_init_session_tags(tag_num, tag_size, prot_op);
     else
         sess = transport_alloc_session(prot_op);
 
     if (IS_ERR(sess))
         return sess;
 
     sess->se_node_acl = core_tpg_check_initiator_node_acl(tpg,
                     (unsigned char *)initiatorname);
     if (!sess->se_node_acl) {
         transport_free_session(sess);
         return ERR_PTR(-EACCES);
     }
     /*
      * Go ahead and perform any remaining fabric setup that is
      * required before transport_register_session().
      */
     if (callback != NULL) {
         int rc = callback(tpg, sess, private);
         if (rc) {
             transport_free_session(sess);
             return ERR_PTR(rc);
         }
     }
 
     transport_register_session(tpg, sess->se_node_acl, sess, private);
     return sess;
 }
 EXPORT_SYMBOL(target_setup_session);
 
 ssize_t target_show_dynamic_sessions(struct se_portal_group *se_tpg, char *page)
 {
     struct se_session *se_sess;
     ssize_t len = 0;
 
     spin_lock_bh(&se_tpg->session_lock);
     list_for_each_entry(se_sess, &se_tpg->tpg_sess_list, sess_list) {
         if (!se_sess->se_node_acl)
             continue;
         if (!se_sess->se_node_acl->dynamic_node_acl)
             continue;
         if (strlen(se_sess->se_node_acl->initiatorname) + 1 + len > PAGE_SIZE)
             break;
 
         len += snprintf(page + len, PAGE_SIZE - len, "%s\n",
                 se_sess->se_node_acl->initiatorname);
         len += 1; /* Include NULL terminator */
     }
     spin_unlock_bh(&se_tpg->session_lock);
 
     return len;
 }
 EXPORT_SYMBOL(target_show_dynamic_sessions);
 
 static void target_complete_nacl(struct kref *kref)
 {
     struct se_node_acl *nacl = container_of(kref,
                 struct se_node_acl, acl_kref);
     struct se_portal_group *se_tpg = nacl->se_tpg;
 
     if (!nacl->dynamic_stop) {
         complete(&nacl->acl_free_comp);
         return;
     }
 
     mutex_lock(&se_tpg->acl_node_mutex);
     list_del_init(&nacl->acl_list);
     mutex_unlock(&se_tpg->acl_node_mutex);
 
     core_tpg_wait_for_nacl_pr_ref(nacl);
     core_free_device_list_for_node(nacl, se_tpg);
     kfree(nacl);
 }
 
 void target_put_nacl(struct se_node_acl *nacl)
 {
     kref_put(&nacl->acl_kref, target_complete_nacl);
 }
 EXPORT_SYMBOL(target_put_nacl);
 
 void transport_deregister_session_configfs(struct se_session *se_sess)
 {
     struct se_node_acl *se_nacl;
     unsigned long flags;
     /*
      * Used by struct se_node_acl's under ConfigFS to locate active struct se_session
      */
     se_nacl = se_sess->se_node_acl;
     if (se_nacl) {
         spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
         if (!list_empty(&se_sess->sess_acl_list))
             list_del_init(&se_sess->sess_acl_list);
         /*
          * If the session list is empty, then clear the pointer.
          * Otherwise, set the struct se_session pointer from the tail
          * element of the per struct se_node_acl active session list.
          */
         if (list_empty(&se_nacl->acl_sess_list))
             se_nacl->nacl_sess = NULL;
         else {
             se_nacl->nacl_sess = container_of(
                     se_nacl->acl_sess_list.prev,
                     struct se_session, sess_acl_list);
         }
         spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
     }
 }
 EXPORT_SYMBOL(transport_deregister_session_configfs);
 
 void transport_free_session(struct se_session *se_sess)
 {
     struct se_node_acl *se_nacl = se_sess->se_node_acl;
 
     /*
      * Drop the se_node_acl->nacl_kref obtained from within
      * core_tpg_get_initiator_node_acl().
      */
     if (se_nacl) {
         struct se_portal_group *se_tpg = se_nacl->se_tpg;
         const struct target_core_fabric_ops *se_tfo = se_tpg->se_tpg_tfo;
         unsigned long flags;
 
         se_sess->se_node_acl = NULL;
 
         /*
          * Also determine if we need to drop the extra ->cmd_kref if
          * it had been previously dynamically generated, and
          * the endpoint is not caching dynamic ACLs.
          */
         mutex_lock(&se_tpg->acl_node_mutex);
         if (se_nacl->dynamic_node_acl &&
             !se_tfo->tpg_check_demo_mode_cache(se_tpg)) {
             spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
             if (list_empty(&se_nacl->acl_sess_list))
                 se_nacl->dynamic_stop = true;
             spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
 
             if (se_nacl->dynamic_stop)
                 list_del_init(&se_nacl->acl_list);
         }
         mutex_unlock(&se_tpg->acl_node_mutex);
 
         if (se_nacl->dynamic_stop)
             target_put_nacl(se_nacl);
 
         target_put_nacl(se_nacl);
     }
     if (se_sess->sess_cmd_map) {
         sbitmap_queue_free(&se_sess->sess_tag_pool);
         kvfree(se_sess->sess_cmd_map);
     }
     transport_uninit_session(se_sess);
     kmem_cache_free(se_sess_cache, se_sess);
 }
 EXPORT_SYMBOL(transport_free_session);
 
 static int target_release_res(struct se_device *dev, void *data)
 {
     struct se_session *sess = data;
 
     if (dev->reservation_holder == sess)
         target_release_reservation(dev);
     return 0;
 }
 
 void transport_deregister_session(struct se_session *se_sess)
 {
     struct se_portal_group *se_tpg = se_sess->se_tpg;
     unsigned long flags;
 
     if (!se_tpg) {
         transport_free_session(se_sess);
         return;
     }
 
     spin_lock_irqsave(&se_tpg->session_lock, flags);
     list_del(&se_sess->sess_list);
     se_sess->se_tpg = NULL;
     se_sess->fabric_sess_ptr = NULL;
     spin_unlock_irqrestore(&se_tpg->session_lock, flags);
 
     /*
      * Since the session is being removed, release SPC-2
      * reservations held by the session that is disappearing.
      */
     target_for_each_device(target_release_res, se_sess);
 
     pr_debug("TARGET_CORE[%s]: Deregistered fabric_sess\n",
         se_tpg->se_tpg_tfo->fabric_name);
     /*
      * If last kref is dropping now for an explicit NodeACL, awake sleeping
      * ->acl_free_comp caller to wakeup configfs se_node_acl->acl_group
      * removal context from within transport_free_session() code.
      *
      * For dynamic ACL, target_put_nacl() uses target_complete_nacl()
      * to release all remaining generate_node_acl=1 created ACL resources.
      */
 
     transport_free_session(se_sess);
 }
 EXPORT_SYMBOL(transport_deregister_session);
 
 void target_remove_session(struct se_session *se_sess)
 {
     transport_deregister_session_configfs(se_sess);
     transport_deregister_session(se_sess);
 }
 EXPORT_SYMBOL(target_remove_session);
 
 static void target_remove_from_state_list(struct se_cmd *cmd)
 {
     struct se_device *dev = cmd->se_dev;
     unsigned long flags;
 
     if (!dev)
         return;
 
     spin_lock_irqsave(&dev->queues[cmd->cpuid].lock, flags);
     if (cmd->state_active) {
         list_del(&cmd->state_list);
         cmd->state_active = false;
     }
     spin_unlock_irqrestore(&dev->queues[cmd->cpuid].lock, flags);
 }
 
 static void target_remove_from_tmr_list(struct se_cmd *cmd)
 {
     struct se_device *dev = NULL;
     unsigned long flags;
 
     if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
         dev = cmd->se_tmr_req->tmr_dev;
 
     if (dev) {
         spin_lock_irqsave(&dev->se_tmr_lock, flags);
         if (cmd->se_tmr_req->tmr_dev)
             list_del_init(&cmd->se_tmr_req->tmr_list);
         spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
     }
 }
 /*
  * This function is called by the target core after the target core has
  * finished processing a SCSI command or SCSI TMF. Both the regular command
  * processing code and the code for aborting commands can call this
  * function. CMD_T_STOP is set if and only if another thread is waiting
  * inside transport_wait_for_tasks() for t_transport_stop_comp.
  */
 static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
 {
     unsigned long flags;
 
     spin_lock_irqsave(&cmd->t_state_lock, flags);
     /*
      * Determine if frontend context caller is requesting the stopping of
      * this command for frontend exceptions.
      */
     if (cmd->transport_state & CMD_T_STOP) {
         pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
             __func__, __LINE__, cmd->tag);
 
         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 
         complete_all(&cmd->t_transport_stop_comp);
         return 1;
     }
     cmd->transport_state &= ~CMD_T_ACTIVE;
     spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 
     /*
      * Some fabric modules like tcm_loop can release their internally
      * allocated I/O reference and struct se_cmd now.
      *
      * Fabric modules are expected to return '1' here if the se_cmd being
      * passed is released at this point, or zero if not being released.
      */
     return cmd->se_tfo->check_stop_free(cmd);
 }
 
 static void transport_lun_remove_cmd(struct se_cmd *cmd)
 {
     struct se_lun *lun = cmd->se_lun;
 
     if (!lun)
         return;
 
     target_remove_from_state_list(cmd);
     target_remove_from_tmr_list(cmd);
 
     if (cmpxchg(&cmd->lun_ref_active, true, false))
         percpu_ref_put(&lun->lun_ref);
 
     /*
      * Clear struct se_cmd->se_lun before the handoff to FE.
      */
     cmd->se_lun = NULL;
 }
 
 static void target_complete_failure_work(struct work_struct *work)
 {
     struct se_cmd *cmd = container_of(work, struct se_cmd, work);
 
     transport_generic_request_failure(cmd, cmd->sense_reason);
 }
 
 /*
  * Used when asking transport to copy Sense Data from the underlying
  * Linux/SCSI struct scsi_cmnd
  */
 static unsigned char *transport_get_sense_buffer(struct se_cmd *cmd)
 {
     struct se_device *dev = cmd->se_dev;
 
     WARN_ON(!cmd->se_lun);
 
     if (!dev)
         return NULL;
 
     if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION)
         return NULL;
 
     cmd->scsi_sense_length = TRANSPORT_SENSE_BUFFER;
 
     pr_debug("HBA_[%u]_PLUG[%s]: Requesting sense for SAM STATUS: 0x%02x\n",
         dev->se_hba->hba_id, dev->transport->name, cmd->scsi_status);
     return cmd->sense_buffer;
 }
 
 void transport_copy_sense_to_cmd(struct se_cmd *cmd, unsigned char *sense)
 {
     unsigned char *cmd_sense_buf;
     unsigned long flags;
 
     spin_lock_irqsave(&cmd->t_state_lock, flags);
     cmd_sense_buf = transport_get_sense_buffer(cmd);
     if (!cmd_sense_buf) {
         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
         return;
     }
 
     cmd->se_cmd_flags |= SCF_TRANSPORT_TASK_SENSE;
     memcpy(cmd_sense_buf, sense, cmd->scsi_sense_length);
     spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 }
 EXPORT_SYMBOL(transport_copy_sense_to_cmd);
 
 static void target_handle_abort(struct se_cmd *cmd)
 {
     bool tas = cmd->transport_state & CMD_T_TAS;
     bool ack_kref = cmd->se_cmd_flags & SCF_ACK_KREF;
     int ret;
 
     pr_debug("tag %#llx: send_abort_response = %d\n", cmd->tag, tas);
 
     if (tas) {
         if (!(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
             cmd->scsi_status = SAM_STAT_TASK_ABORTED;
             pr_debug("Setting SAM_STAT_TASK_ABORTED status for CDB: 0x%02x, ITT: 0x%08llx\n",
                  cmd->t_task_cdb[0], cmd->tag);
             trace_target_cmd_complete(cmd);
             ret = cmd->se_tfo->queue_status(cmd);
             if (ret) {
                 transport_handle_queue_full(cmd, cmd->se_dev,
                                 ret, false);
                 return;
             }
         } else {
             cmd->se_tmr_req->response = TMR_FUNCTION_REJECTED;
             cmd->se_tfo->queue_tm_rsp(cmd);
         }
     } else {
         /*
          * Allow the fabric driver to unmap any resources before
          * releasing the descriptor via TFO->release_cmd().
          */
         cmd->se_tfo->aborted_task(cmd);
         if (ack_kref)
             WARN_ON_ONCE(target_put_sess_cmd(cmd) != 0);
         /*
          * To do: establish a unit attention condition on the I_T
          * nexus associated with cmd. See also the paragraph "Aborting
          * commands" in SAM.
          */
     }
 
     WARN_ON_ONCE(kref_read(&cmd->cmd_kref) == 0);
 
     transport_lun_remove_cmd(cmd);
 
     transport_cmd_check_stop_to_fabric(cmd);
 }
 
 static void target_abort_work(struct work_struct *work)
 {
     struct se_cmd *cmd = container_of(work, struct se_cmd, work);
 
     target_handle_abort(cmd);
 }
 
 static bool target_cmd_interrupted(struct se_cmd *cmd)
 {
     int post_ret;
 
     if (cmd->transport_state & CMD_T_ABORTED) {
         if (cmd->transport_complete_callback)
             cmd->transport_complete_callback(cmd, false, &post_ret);
         INIT_WORK(&cmd->work, target_abort_work);
         queue_work(target_completion_wq, &cmd->work);
         return true;
     } else if (cmd->transport_state & CMD_T_STOP) {
         if (cmd->transport_complete_callback)
             cmd->transport_complete_callback(cmd, false, &post_ret);
         complete_all(&cmd->t_transport_stop_comp);
         return true;
     }
 
     return false;
 }
 
 /* May be called from interrupt context so must not sleep. */
 void target_complete_cmd_with_sense(struct se_cmd *cmd, u8 scsi_status,
                     sense_reason_t sense_reason)
 {
     struct se_wwn *wwn = cmd->se_sess->se_tpg->se_tpg_wwn;
     int success, cpu;
     unsigned long flags;
 
     if (target_cmd_interrupted(cmd))
         return;
 
     cmd->scsi_status = scsi_status;
     cmd->sense_reason = sense_reason;
 
     spin_lock_irqsave(&cmd->t_state_lock, flags);
     switch (cmd->scsi_status) {
     case SAM_STAT_CHECK_CONDITION:
         if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
             success = 1;
         else
             success = 0;
         break;
     default:
         success = 1;
         break;
     }
 
     cmd->t_state = TRANSPORT_COMPLETE;
     cmd->transport_state |= (CMD_T_COMPLETE | CMD_T_ACTIVE);
     spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 
     INIT_WORK(&cmd->work, success ? target_complete_ok_work :
           target_complete_failure_work);
 
     if (!wwn || wwn->cmd_compl_affinity == SE_COMPL_AFFINITY_CPUID)
         cpu = cmd->cpuid;
     else
         cpu = wwn->cmd_compl_affinity;
 
     queue_work_on(cpu, target_completion_wq, &cmd->work);
 }
 EXPORT_SYMBOL(target_complete_cmd_with_sense);
 
 void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
 {
     target_complete_cmd_with_sense(cmd, scsi_status, scsi_status ?
                   TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE :
                   TCM_NO_SENSE);
 }
 EXPORT_SYMBOL(target_complete_cmd);
 
 void target_set_cmd_data_length(struct se_cmd *cmd, int length)
 {
     if (length < cmd->data_length) {
         if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
             cmd->residual_count += cmd->data_length - length;
         } else {
             cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
             cmd->residual_count = cmd->data_length - length;
         }
 
         cmd->data_length = length;
     }
 }
 EXPORT_SYMBOL(target_set_cmd_data_length);
 
 void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length)
 {
     if (scsi_status == SAM_STAT_GOOD ||
         cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL) {
         target_set_cmd_data_length(cmd, length);
     }
 
     target_complete_cmd(cmd, scsi_status);
 }
 EXPORT_SYMBOL(target_complete_cmd_with_length);
 
 static void target_add_to_state_list(struct se_cmd *cmd)
 {
     struct se_device *dev = cmd->se_dev;
     unsigned long flags;
 
     spin_lock_irqsave(&dev->queues[cmd->cpuid].lock, flags);
     if (!cmd->state_active) {
         list_add_tail(&cmd->state_list,
                   &dev->queues[cmd->cpuid].state_list);
         cmd->state_active = true;
     }
     spin_unlock_irqrestore(&dev->queues[cmd->cpuid].lock, flags);
 }
 
 /*
  * Handle QUEUE_FULL / -EAGAIN and -ENOMEM status
  */
 static void transport_write_pending_qf(struct se_cmd *cmd);
 static void transport_complete_qf(struct se_cmd *cmd);
 
 void target_qf_do_work(struct work_struct *work)
 {
     struct se_device *dev = container_of(work, struct se_device,
                     qf_work_queue);
     LIST_HEAD(qf_cmd_list);
     struct se_cmd *cmd, *cmd_tmp;
 
     spin_lock_irq(&dev->qf_cmd_lock);
     list_splice_init(&dev->qf_cmd_list, &qf_cmd_list);
     spin_unlock_irq(&dev->qf_cmd_lock);
 
     list_for_each_entry_safe(cmd, cmd_tmp, &qf_cmd_list, se_qf_node) {
         list_del(&cmd->se_qf_node);
         atomic_dec_mb(&dev->dev_qf_count);
 
         pr_debug("Processing %s cmd: %p QUEUE_FULL in work queue"
             " context: %s\n", cmd->se_tfo->fabric_name, cmd,
             (cmd->t_state == TRANSPORT_COMPLETE_QF_OK) ? "COMPLETE_OK" :
             (cmd->t_state == TRANSPORT_COMPLETE_QF_WP) ? "WRITE_PENDING"
             : "UNKNOWN");
 
         if (cmd->t_state == TRANSPORT_COMPLETE_QF_WP)
             transport_write_pending_qf(cmd);
         else if (cmd->t_state == TRANSPORT_COMPLETE_QF_OK ||
              cmd->t_state == TRANSPORT_COMPLETE_QF_ERR)
             transport_complete_qf(cmd);
     }
 }
 
 unsigned char *transport_dump_cmd_direction(struct se_cmd *cmd)
 {
     switch (cmd->data_direction) {
     case DMA_NONE:
         return "NONE";
     case DMA_FROM_DEVICE:
         return "READ";
     case DMA_TO_DEVICE:
         return "WRITE";
     case DMA_BIDIRECTIONAL:
         return "BIDI";
     default:
         break;
     }
 
     return "UNKNOWN";
 }
 
 void transport_dump_dev_state(
     struct se_device *dev,
     char *b,
     int *bl)
 {
     *bl += sprintf(b + *bl, "Status: ");
     if (dev->export_count)
         *bl += sprintf(b + *bl, "ACTIVATED");
     else
         *bl += sprintf(b + *bl, "DEACTIVATED");
 
     *bl += sprintf(b + *bl, "  Max Queue Depth: %d", dev->queue_depth);
     *bl += sprintf(b + *bl, "  SectorSize: %u  HwMaxSectors: %u\n",
         dev->dev_attrib.block_size,
         dev->dev_attrib.hw_max_sectors);
     *bl += sprintf(b + *bl, "        ");
 }
 
 void transport_dump_vpd_proto_id(
     struct t10_vpd *vpd,
     unsigned char *p_buf,
     int p_buf_len)
 {
     unsigned char buf[VPD_TMP_BUF_SIZE];
     int len;
 
     memset(buf, 0, VPD_TMP_BUF_SIZE);
     len = sprintf(buf, "T10 VPD Protocol Identifier: ");
 
     switch (vpd->protocol_identifier) {
     case 0x00:
         sprintf(buf+len, "Fibre Channel\n");
         break;
     case 0x10:
         sprintf(buf+len, "Parallel SCSI\n");
         break;
     case 0x20:
         sprintf(buf+len, "SSA\n");
         break;
     case 0x30:
         sprintf(buf+len, "IEEE 1394\n");
         break;
     case 0x40:
         sprintf(buf+len, "SCSI Remote Direct Memory Access"
                 " Protocol\n");
         break;
     case 0x50:
         sprintf(buf+len, "Internet SCSI (iSCSI)\n");
         break;
     case 0x60:
         sprintf(buf+len, "SAS Serial SCSI Protocol\n");
         break;
     case 0x70:
         sprintf(buf+len, "Automation/Drive Interface Transport"
                 " Protocol\n");
         break;
     case 0x80:
         sprintf(buf+len, "AT Attachment Interface ATA/ATAPI\n");
         break;
     default:
         sprintf(buf+len, "Unknown 0x%02x\n",
                 vpd->protocol_identifier);
         break;
     }
 
     if (p_buf)
         strncpy(p_buf, buf, p_buf_len);
     else
         pr_debug("%s", buf);
 }
 
 void
 transport_set_vpd_proto_id(struct t10_vpd *vpd, unsigned char *page_83)
 {
     /*
      * Check if the Protocol Identifier Valid (PIV) bit is set..
      *
      * from spc3r23.pdf section 7.5.1
      */
      if (page_83[1] & 0x80) {
         vpd->protocol_identifier = (page_83[0] & 0xf0);
         vpd->protocol_identifier_set = 1;
         transport_dump_vpd_proto_id(vpd, NULL, 0);
     }
 }
 EXPORT_SYMBOL(transport_set_vpd_proto_id);
 
 int transport_dump_vpd_assoc(
     struct t10_vpd *vpd,
     unsigned char *p_buf,
     int p_buf_len)
 {
     unsigned char buf[VPD_TMP_BUF_SIZE];
     int ret = 0;
     int len;
 
     memset(buf, 0, VPD_TMP_BUF_SIZE);
     len = sprintf(buf, "T10 VPD Identifier Association: ");
 
     switch (vpd->association) {
     case 0x00:
         sprintf(buf+len, "addressed logical unit\n");
         break;
     case 0x10:
         sprintf(buf+len, "target port\n");
         break;
     case 0x20:
         sprintf(buf+len, "SCSI target device\n");
         break;
     default:
         sprintf(buf+len, "Unknown 0x%02x\n", vpd->association);
         ret = -EINVAL;
         break;
     }
 
     if (p_buf)
         strncpy(p_buf, buf, p_buf_len);
     else
         pr_debug("%s", buf);
 
     return ret;
 }
 
 int transport_set_vpd_assoc(struct t10_vpd *vpd, unsigned char *page_83)
 {
     /*
      * The VPD identification association..
      *
      * from spc3r23.pdf Section 7.6.3.1 Table 297
      */
     vpd->association = (page_83[1] & 0x30);
     return transport_dump_vpd_assoc(vpd, NULL, 0);
 }
 EXPORT_SYMBOL(transport_set_vpd_assoc);
 
 int transport_dump_vpd_ident_type(
     struct t10_vpd *vpd,
     unsigned char *p_buf,
     int p_buf_len)
 {
     unsigned char buf[VPD_TMP_BUF_SIZE];
     int ret = 0;
     int len;
 
     memset(buf, 0, VPD_TMP_BUF_SIZE);
     len = sprintf(buf, "T10 VPD Identifier Type: ");
 
     switch (vpd->device_identifier_type) {
     case 0x00:
         sprintf(buf+len, "Vendor specific\n");
         break;
     case 0x01:
         sprintf(buf+len, "T10 Vendor ID based\n");
         break;
     case 0x02:
         sprintf(buf+len, "EUI-64 based\n");
         break;
     case 0x03:
         sprintf(buf+len, "NAA\n");
         break;
     case 0x04:
         sprintf(buf+len, "Relative target port identifier\n");
         break;
     case 0x08:
         sprintf(buf+len, "SCSI name string\n");
         break;
     default:
         sprintf(buf+len, "Unsupported: 0x%02x\n",
                 vpd->device_identifier_type);
         ret = -EINVAL;
         break;
     }
 
     if (p_buf) {
         if (p_buf_len < strlen(buf)+1)
             return -EINVAL;
         strncpy(p_buf, buf, p_buf_len);
     } else {
         pr_debug("%s", buf);
     }
 
     return ret;
 }
 
 int transport_set_vpd_ident_type(struct t10_vpd *vpd, unsigned char *page_83)
 {
     /*
      * The VPD identifier type..
      *
      * from spc3r23.pdf Section 7.6.3.1 Table 298
      */
     vpd->device_identifier_type = (page_83[1] & 0x0f);
     return transport_dump_vpd_ident_type(vpd, NULL, 0);
 }
 EXPORT_SYMBOL(transport_set_vpd_ident_type);
 
 int transport_dump_vpd_ident(
     struct t10_vpd *vpd,
     unsigned char *p_buf,
     int p_buf_len)
 {
     unsigned char buf[VPD_TMP_BUF_SIZE];
     int ret = 0;
 
     memset(buf, 0, VPD_TMP_BUF_SIZE);
 
     switch (vpd->device_identifier_code_set) {
     case 0x01: /* Binary */
         snprintf(buf, sizeof(buf),
             "T10 VPD Binary Device Identifier: %s\n",
             &vpd->device_identifier[0]);
         break;
     case 0x02: /* ASCII */
         snprintf(buf, sizeof(buf),
             "T10 VPD ASCII Device Identifier: %s\n",
             &vpd->device_identifier[0]);
         break;
     case 0x03: /* UTF-8 */
         snprintf(buf, sizeof(buf),
             "T10 VPD UTF-8 Device Identifier: %s\n",
             &vpd->device_identifier[0]);
         break;
     default:
         sprintf(buf, "T10 VPD Device Identifier encoding unsupported:"
             " 0x%02x", vpd->device_identifier_code_set);
         ret = -EINVAL;
         break;
     }
 
     if (p_buf)
         strncpy(p_buf, buf, p_buf_len);
     else
         pr_debug("%s", buf);
 
     return ret;
 }
 
 int
 transport_set_vpd_ident(struct t10_vpd *vpd, unsigned char *page_83)
 {
     static const char hex_str[] = "0123456789abcdef";
     int j = 0, i = 4; /* offset to start of the identifier */
 
     /*
      * The VPD Code Set (encoding)
      *
      * from spc3r23.pdf Section 7.6.3.1 Table 296
      */
     vpd->device_identifier_code_set = (page_83[0] & 0x0f);
     switch (vpd->device_identifier_code_set) {
     case 0x01: /* Binary */
         vpd->device_identifier[j++] =
                 hex_str[vpd->device_identifier_type];
         while (i < (4 + page_83[3])) {
             vpd->device_identifier[j++] =
                 hex_str[(page_83[i] & 0xf0) >> 4];
             vpd->device_identifier[j++] =
                 hex_str[page_83[i] & 0x0f];
             i++;
         }
         break;
     case 0x02: /* ASCII */
     case 0x03: /* UTF-8 */
         while (i < (4 + page_83[3]))
             vpd->device_identifier[j++] = page_83[i++];
         break;
     default:
         break;
     }
 
     return transport_dump_vpd_ident(vpd, NULL, 0);
 }
 EXPORT_SYMBOL(transport_set_vpd_ident);
 
 static sense_reason_t
 target_check_max_data_sg_nents(struct se_cmd *cmd, struct se_device *dev,
                    unsigned int size)
 {
     u32 mtl;
 
     if (!cmd->se_tfo->max_data_sg_nents)
         return TCM_NO_SENSE;
     /*
      * Check if fabric enforced maximum SGL entries per I/O descriptor
      * exceeds se_cmd->data_length.  If true, set SCF_UNDERFLOW_BIT +
      * residual_count and reduce original cmd->data_length to maximum
      * length based on single PAGE_SIZE entry scatter-lists.
      */
     mtl = (cmd->se_tfo->max_data_sg_nents * PAGE_SIZE);
     if (cmd->data_length > mtl) {
         /*
          * If an existing CDB overflow is present, calculate new residual
          * based on CDB size minus fabric maximum transfer length.
          *
          * If an existing CDB underflow is present, calculate new residual
          * based on original cmd->data_length minus fabric maximum transfer
          * length.
          *
          * Otherwise, set the underflow residual based on cmd->data_length
          * minus fabric maximum transfer length.
          */
         if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
             cmd->residual_count = (size - mtl);
         } else if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
             u32 orig_dl = size + cmd->residual_count;
             cmd->residual_count = (orig_dl - mtl);
         } else {
             cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
             cmd->residual_count = (cmd->data_length - mtl);
         }
         cmd->data_length = mtl;
         /*
          * Reset sbc_check_prot() calculated protection payload
          * length based upon the new smaller MTL.
          */
         if (cmd->prot_length) {
             u32 sectors = (mtl / dev->dev_attrib.block_size);
             cmd->prot_length = dev->prot_length * sectors;
         }
     }
     return TCM_NO_SENSE;
 }
 
 /**
  * target_cmd_size_check - Check whether there will be a residual.
  * @cmd: SCSI command.
  * @size: Data buffer size derived from CDB. The data buffer size provided by
  *   the SCSI transport driver is available in @cmd->data_length.
  *
  * Compare the data buffer size from the CDB with the data buffer limit from the transport
  * header. Set @cmd->residual_count and SCF_OVERFLOW_BIT or SCF_UNDERFLOW_BIT if necessary.
  *
  * Note: target drivers set @cmd->data_length by calling __target_init_cmd().
  *
  * Return: TCM_NO_SENSE
  */
 sense_reason_t
 target_cmd_size_check(struct se_cmd *cmd, unsigned int size)
 {
     struct se_device *dev = cmd->se_dev;
 
     if (cmd->unknown_data_length) {
         cmd->data_length = size;
     } else if (size != cmd->data_length) {
         pr_warn_ratelimited("TARGET_CORE[%s]: Expected Transfer Length:"
             " %u does not match SCSI CDB Length: %u for SAM Opcode:"
             " 0x%02x\n", cmd->se_tfo->fabric_name,
                 cmd->data_length, size, cmd->t_task_cdb[0]);
         /*
          * For READ command for the overflow case keep the existing
          * fabric provided ->data_length. Otherwise for the underflow
          * case, reset ->data_length to the smaller SCSI expected data
          * transfer length.
          */
         if (size > cmd->data_length) {
             cmd->se_cmd_flags |= SCF_OVERFLOW_BIT;
             cmd->residual_count = (size - cmd->data_length);
         } else {
             cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
             cmd->residual_count = (cmd->data_length - size);
             /*
              * Do not truncate ->data_length for WRITE command to
              * dump all payload
              */
             if (cmd->data_direction == DMA_FROM_DEVICE) {
                 cmd->data_length = size;
             }
         }
 
         if (cmd->data_direction == DMA_TO_DEVICE) {
             if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
                 pr_err_ratelimited("Rejecting underflow/overflow"
                            " for WRITE data CDB\n");
                 return TCM_INVALID_FIELD_IN_COMMAND_IU;
             }
             /*
              * Some fabric drivers like iscsi-target still expect to
              * always reject overflow writes.  Reject this case until
              * full fabric driver level support for overflow writes
              * is introduced tree-wide.
              */
             if (size > cmd->data_length) {
                 pr_err_ratelimited("Rejecting overflow for"
                            " WRITE control CDB\n");
                 return TCM_INVALID_CDB_FIELD;
             }
         }
     }
 
     return target_check_max_data_sg_nents(cmd, dev, size);
 
 }
 
 /*
  * Used by fabric modules containing a local struct se_cmd within their
  * fabric dependent per I/O descriptor.
  *
  * Preserves the value of @cmd->tag.
  */
 void __target_init_cmd(
     struct se_cmd *cmd,
     const struct target_core_fabric_ops *tfo,
     struct se_session *se_sess,
     u32 data_length,
     int data_direction,
     int task_attr,
     unsigned char *sense_buffer, u64 unpacked_lun)
 {
     INIT_LIST_HEAD(&cmd->se_delayed_node);
     INIT_LIST_HEAD(&cmd->se_qf_node);
     INIT_LIST_HEAD(&cmd->state_list);
     init_completion(&cmd->t_transport_stop_comp);
     cmd->free_compl = NULL;
     cmd->abrt_compl = NULL;
     spin_lock_init(&cmd->t_state_lock);
     INIT_WORK(&cmd->work, NULL);
     kref_init(&cmd->cmd_kref);
 
     cmd->t_task_cdb = &cmd->__t_task_cdb[0];
     cmd->se_tfo = tfo;
     cmd->se_sess = se_sess;
     cmd->data_length = data_length;
     cmd->data_direction = data_direction;
     cmd->sam_task_attr = task_attr;
     cmd->sense_buffer = sense_buffer;
     cmd->orig_fe_lun = unpacked_lun;
 
     if (!(cmd->se_cmd_flags & SCF_USE_CPUID))
         cmd->cpuid = raw_smp_processor_id();
 
     cmd->state_active = false;
 }
 EXPORT_SYMBOL(__target_init_cmd);
 
 static sense_reason_t
 transport_check_alloc_task_attr(struct se_cmd *cmd)
 {
     struct se_device *dev = cmd->se_dev;
 
     /*
      * Check if SAM Task Attribute emulation is enabled for this
      * struct se_device storage object
      */
     if (dev->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
         return 0;
 
     if (cmd->sam_task_attr == TCM_ACA_TAG) {
         pr_debug("SAM Task Attribute ACA"
             " emulation is not supported\n");
         return TCM_INVALID_CDB_FIELD;
     }
 
     return 0;
 }
 
 sense_reason_t
 target_cmd_init_cdb(struct se_cmd *cmd, unsigned char *cdb, gfp_t gfp)
 {
     sense_reason_t ret;
 
     /*
      * Ensure that the received CDB is less than the max (252 + 8) bytes
      * for VARIABLE_LENGTH_CMD
      */
     if (scsi_command_size(cdb) > SCSI_MAX_VARLEN_CDB_SIZE) {
         pr_err("Received SCSI CDB with command_size: %d that"
             " exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
             scsi_command_size(cdb), SCSI_MAX_VARLEN_CDB_SIZE);
         ret = TCM_INVALID_CDB_FIELD;
         goto err;
     }
     /*
      * If the received CDB is larger than TCM_MAX_COMMAND_SIZE,
      * allocate the additional extended CDB buffer now..  Otherwise
      * setup the pointer from __t_task_cdb to t_task_cdb.
      */
     if (scsi_command_size(cdb) > sizeof(cmd->__t_task_cdb)) {
         cmd->t_task_cdb = kzalloc(scsi_command_size(cdb), gfp);
         if (!cmd->t_task_cdb) {
             pr_err("Unable to allocate cmd->t_task_cdb"
                 " %u > sizeof(cmd->__t_task_cdb): %lu ops\n",
                 scsi_command_size(cdb),
                 (unsigned long)sizeof(cmd->__t_task_cdb));
             ret = TCM_OUT_OF_RESOURCES;
             goto err;
         }
     }
     /*
      * Copy the original CDB into cmd->
      */
     memcpy(cmd->t_task_cdb, cdb, scsi_command_size(cdb));
 
     trace_target_sequencer_start(cmd);
     return 0;
 
 err:
     /*
      * Copy the CDB here to allow trace_target_cmd_complete() to
      * print the cdb to the trace buffers.
      */
     memcpy(cmd->t_task_cdb, cdb, min(scsi_command_size(cdb),
                      (unsigned int)TCM_MAX_COMMAND_SIZE));
     return ret;
 }
 EXPORT_SYMBOL(target_cmd_init_cdb);
 
 sense_reason_t
 target_cmd_parse_cdb(struct se_cmd *cmd)
 {
     struct se_device *dev = cmd->se_dev;
     sense_reason_t ret;
 
     ret = dev->transport->parse_cdb(cmd);
     if (ret == TCM_UNSUPPORTED_SCSI_OPCODE)
         pr_debug_ratelimited("%s/%s: Unsupported SCSI Opcode 0x%02x, sending CHECK_CONDITION.\n",
                      cmd->se_tfo->fabric_name,
                      cmd->se_sess->se_node_acl->initiatorname,
                      cmd->t_task_cdb[0]);
     if (ret)
         return ret;
 
     ret = transport_check_alloc_task_attr(cmd);
     if (ret)
         return ret;
 
     cmd->se_cmd_flags |= SCF_SUPPORTED_SAM_OPCODE;
     atomic_long_inc(&cmd->se_lun->lun_stats.cmd_pdus);
     return 0;
 }
 EXPORT_SYMBOL(target_cmd_parse_cdb);
 
 /*
  * Used by fabric module frontends to queue tasks directly.
  * May only be used from process context.
  */
 int transport_handle_cdb_direct(
     struct se_cmd *cmd)
 {
     sense_reason_t ret;
 
     might_sleep();
 
     if (!cmd->se_lun) {
         dump_stack();
         pr_err("cmd->se_lun is NULL\n");
         return -EINVAL;
     }
 
     /*
      * Set TRANSPORT_NEW_CMD state and CMD_T_ACTIVE to ensure that
      * outstanding descriptors are handled correctly during shutdown via
      * transport_wait_for_tasks()
      *
      * Also, we don't take cmd->t_state_lock here as we only expect
      * this to be called for initial descriptor submission.
      */
     cmd->t_state = TRANSPORT_NEW_CMD;
     cmd->transport_state |= CMD_T_ACTIVE;
 
     /*
      * transport_generic_new_cmd() is already handling QUEUE_FULL,
      * so follow TRANSPORT_NEW_CMD processing thread context usage
      * and call transport_generic_request_failure() if necessary..
      */
     ret = transport_generic_new_cmd(cmd);
     if (ret)
         transport_generic_request_failure(cmd, ret);
     return 0;
 }
 EXPORT_SYMBOL(transport_handle_cdb_direct);
 
 sense_reason_t
 transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
         u32 sgl_count, struct scatterlist *sgl_bidi, u32 sgl_bidi_count)
 {
     if (!sgl || !sgl_count)
         return 0;
 
     /*
      * Reject SCSI data overflow with map_mem_to_cmd() as incoming
      * scatterlists already have been set to follow what the fabric
      * passes for the original expected data transfer length.
      */
     if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
         pr_warn("Rejecting SCSI DATA overflow for fabric using"
             " SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC\n");
         return TCM_INVALID_CDB_FIELD;
     }
 
     cmd->t_data_sg = sgl;
     cmd->t_data_nents = sgl_count;
     cmd->t_bidi_data_sg = sgl_bidi;
     cmd->t_bidi_data_nents = sgl_bidi_count;
 
     cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
     return 0;
 }
 
 /**
  * target_init_cmd - initialize se_cmd
  * @se_cmd: command descriptor to init
  * @se_sess: associated se_sess for endpoint
  * @sense: pointer to SCSI sense buffer
  * @unpacked_lun: unpacked LUN to reference for struct se_lun
  * @data_length: fabric expected data transfer length
  * @task_attr: SAM task attribute
  * @data_dir: DMA data direction
  * @flags: flags for command submission from target_sc_flags_tables
  *
  * Task tags are supported if the caller has set @se_cmd->tag.
  *
  * Returns:
  *  - less than zero to signal active I/O shutdown failure.
  *  - zero on success.
  *
  * If the fabric driver calls target_stop_session, then it must check the
  * return code and handle failures. This will never fail for other drivers,
  * and the return code can be ignored.
  */
 int target_init_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
             unsigned char *sense, u64 unpacked_lun,
             u32 data_length, int task_attr, int data_dir, int flags)
 {
     struct se_portal_group *se_tpg;
 
     se_tpg = se_sess->se_tpg;
     BUG_ON(!se_tpg);
     BUG_ON(se_cmd->se_tfo || se_cmd->se_sess);
 
     if (flags & TARGET_SCF_USE_CPUID)
         se_cmd->se_cmd_flags |= SCF_USE_CPUID;
     /*
      * Signal bidirectional data payloads to target-core
      */
     if (flags & TARGET_SCF_BIDI_OP)
         se_cmd->se_cmd_flags |= SCF_BIDI;
 
     if (flags & TARGET_SCF_UNKNOWN_SIZE)
         se_cmd->unknown_data_length = 1;
     /*
      * Initialize se_cmd for target operation.  From this point
      * exceptions are handled by sending exception status via
      * target_core_fabric_ops->queue_status() callback
      */
     __target_init_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess, data_length,
               data_dir, task_attr, sense, unpacked_lun);
 
     /*
      * Obtain struct se_cmd->cmd_kref reference. A second kref_get here is
      * necessary for fabrics using TARGET_SCF_ACK_KREF that expect a second
      * kref_put() to happen during fabric packet acknowledgement.
      */
     return target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
 }
 EXPORT_SYMBOL_GPL(target_init_cmd);
 
 /**
  * target_submit_prep - prepare cmd for submission
  * @se_cmd: command descriptor to prep
  * @cdb: pointer to SCSI CDB
  * @sgl: struct scatterlist memory for unidirectional mapping
  * @sgl_count: scatterlist count for unidirectional mapping
  * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping
  * @sgl_bidi_count: scatterlist count for bidirectional READ mapping
  * @sgl_prot: struct scatterlist memory protection information
  * @sgl_prot_count: scatterlist count for protection information
  * @gfp: gfp allocation type
  *
  * Returns:
  *  - less than zero to signal failure.
  *  - zero on success.
  *
  * If failure is returned, lio will the callers queue_status to complete
  * the cmd.
  */
 int target_submit_prep(struct se_cmd *se_cmd, unsigned char *cdb,
                struct scatterlist *sgl, u32 sgl_count,
                struct scatterlist *sgl_bidi, u32 sgl_bidi_count,
                struct scatterlist *sgl_prot, u32 sgl_prot_count,
                gfp_t gfp)
 {
     sense_reason_t rc;
 
     rc = target_cmd_init_cdb(se_cmd, cdb, gfp);
     if (rc)
         goto send_cc_direct;
 
     /*
      * Locate se_lun pointer and attach it to struct se_cmd
      */
     rc = transport_lookup_cmd_lun(se_cmd);
     if (rc)
         goto send_cc_direct;
 
     rc = target_cmd_parse_cdb(se_cmd);
     if (rc != 0)
         goto generic_fail;
 
     /*
      * Save pointers for SGLs containing protection information,
      * if present.
      */
     if (sgl_prot_count) {
         se_cmd->t_prot_sg = sgl_prot;
         se_cmd->t_prot_nents = sgl_prot_count;
         se_cmd->se_cmd_flags |= SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC;
     }
 
     /*
      * When a non zero sgl_count has been passed perform SGL passthrough
      * mapping for pre-allocated fabric memory instead of having target
      * core perform an internal SGL allocation..
      */
     if (sgl_count != 0) {
         BUG_ON(!sgl);
 
         rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count,
                 sgl_bidi, sgl_bidi_count);
         if (rc != 0)
             goto generic_fail;
     }
 
     return 0;
 
 send_cc_direct:
     transport_send_check_condition_and_sense(se_cmd, rc, 0);
     target_put_sess_cmd(se_cmd);
     return -EIO;
 
 generic_fail:
     transport_generic_request_failure(se_cmd, rc);
     return -EIO;
 }
 EXPORT_SYMBOL_GPL(target_submit_prep);
 
 /**
  * target_submit - perform final initialization and submit cmd to LIO core
  * @se_cmd: command descriptor to submit
  *
  * target_submit_prep must have been called on the cmd, and this must be
  * called from process context.
  */
 void target_submit(struct se_cmd *se_cmd)
 {
     struct scatterlist *sgl = se_cmd->t_data_sg;
     unsigned char *buf = NULL;
 
     might_sleep();
 
     if (se_cmd->t_data_nents != 0) {
         BUG_ON(!sgl);
         /*
          * A work-around for tcm_loop as some userspace code via
          * scsi-generic do not memset their associated read buffers,
          * so go ahead and do that here for type non-data CDBs.  Also
          * note that this is currently guaranteed to be a single SGL
          * for this case by target core in target_setup_cmd_from_cdb()
          * -> transport_generic_cmd_sequencer().
          */
         if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
              se_cmd->data_direction == DMA_FROM_DEVICE) {
             if (sgl)
                 buf = kmap(sg_page(sgl)) + sgl->offset;
 
             if (buf) {
                 memset(buf, 0, sgl->length);
                 kunmap(sg_page(sgl));
             }
         }
 
     }
 
     /*
      * Check if we need to delay processing because of ALUA
      * Active/NonOptimized primary access state..
      */
     core_alua_check_nonop_delay(se_cmd);
 
     transport_handle_cdb_direct(se_cmd);
 }
 EXPORT_SYMBOL_GPL(target_submit);
 
 /**
  * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd
  *
  * @se_cmd: command descriptor to submit
  * @se_sess: associated se_sess for endpoint
  * @cdb: pointer to SCSI CDB
  * @sense: pointer to SCSI sense buffer
  * @unpacked_lun: unpacked LUN to reference for struct se_lun
  * @data_length: fabric expected data transfer length
  * @task_attr: SAM task attribute
  * @data_dir: DMA data direction
  * @flags: flags for command submission from target_sc_flags_tables
  *
  * Task tags are supported if the caller has set @se_cmd->tag.
  *
  * This may only be called from process context, and also currently
  * assumes internal allocation of fabric payload buffer by target-core.
  *
  * It also assumes interal target core SGL memory allocation.
  *
  * This function must only be used by drivers that do their own
  * sync during shutdown and does not use target_stop_session. If there
  * is a failure this function will call into the fabric driver's
  * queue_status with a CHECK_CONDITION.
  */
 void target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
         unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
         u32 data_length, int task_attr, int data_dir, int flags)
 {
     int rc;
 
     rc = target_init_cmd(se_cmd, se_sess, sense, unpacked_lun, data_length,
                  task_attr, data_dir, flags);
     WARN(rc, "Invalid target_submit_cmd use. Driver must not use target_stop_session or call target_init_cmd directly.\n");
     if (rc)
         return;
 
     if (target_submit_prep(se_cmd, cdb, NULL, 0, NULL, 0, NULL, 0,
                    GFP_KERNEL))
         return;
 
     target_submit(se_cmd);
 }
 EXPORT_SYMBOL(target_submit_cmd);
 
 
 static struct se_dev_plug *target_plug_device(struct se_device *se_dev)
 {
     struct se_dev_plug *se_plug;
 
     if (!se_dev->transport->plug_device)
         return NULL;
 
     se_plug = se_dev->transport->plug_device(se_dev);
     if (!se_plug)
         return NULL;
 
     se_plug->se_dev = se_dev;
     /*
      * We have a ref to the lun at this point, but the cmds could
      * complete before we unplug, so grab a ref to the se_device so we
      * can call back into the backend.
      */
     config_group_get(&se_dev->dev_group);
     return se_plug;
 }
 
 static void target_unplug_device(struct se_dev_plug *se_plug)
 {
     struct se_device *se_dev = se_plug->se_dev;
 
     se_dev->transport->unplug_device(se_plug);
     config_group_put(&se_dev->dev_group);
 }
 
 void target_queued_submit_work(struct work_struct *work)
 {
     struct se_cmd_queue *sq = container_of(work, struct se_cmd_queue, work);
     struct se_cmd *se_cmd, *next_cmd;
     struct se_dev_plug *se_plug = NULL;
     struct se_device *se_dev = NULL;
     struct llist_node *cmd_list;
 
     cmd_list = llist_del_all(&sq->cmd_list);
     if (!cmd_list)
         /* Previous call took what we were queued to submit */
         return;
 
     cmd_list = llist_reverse_order(cmd_list);
     llist_for_each_entry_safe(se_cmd, next_cmd, cmd_list, se_cmd_list) {
         if (!se_dev) {
             se_dev = se_cmd->se_dev;
             se_plug = target_plug_device(se_dev);
         }
 
         target_submit(se_cmd);
     }
 
     if (se_plug)
         target_unplug_device(se_plug);
 }
 
 /**
  * target_queue_submission - queue the cmd to run on the LIO workqueue
  * @se_cmd: command descriptor to submit
  */
 void target_queue_submission(struct se_cmd *se_cmd)
 {
     struct se_device *se_dev = se_cmd->se_dev;
     int cpu = se_cmd->cpuid;
     struct se_cmd_queue *sq;
 
     sq = &se_dev->queues[cpu].sq;
     llist_add(&se_cmd->se_cmd_list, &sq->cmd_list);
     queue_work_on(cpu, target_submission_wq, &sq->work);
 }
 EXPORT_SYMBOL_GPL(target_queue_submission);
 
 static void target_complete_tmr_failure(struct work_struct *work)
 {
     struct se_cmd *se_cmd = container_of(work, struct se_cmd, work);
 
     se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
     se_cmd->se_tfo->queue_tm_rsp(se_cmd);
 
     transport_lun_remove_cmd(se_cmd);
     transport_cmd_check_stop_to_fabric(se_cmd);
 }
 
 /**
  * target_submit_tmr - lookup unpacked lun and submit uninitialized se_cmd
  *                     for TMR CDBs
  *
  * @se_cmd: command descriptor to submit
  * @se_sess: associated se_sess for endpoint
  * @sense: pointer to SCSI sense buffer
  * @unpacked_lun: unpacked LUN to reference for struct se_lun
  * @fabric_tmr_ptr: fabric context for TMR req
  * @tm_type: Type of TM request
  * @gfp: gfp type for caller
  * @tag: referenced task tag for TMR_ABORT_TASK
  * @flags: submit cmd flags
  *
  * Callable from all contexts.
  **/
 
 int target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,
         unsigned char *sense, u64 unpacked_lun,
         void *fabric_tmr_ptr, unsigned char tm_type,
         gfp_t gfp, u64 tag, int flags)
 {
     struct se_portal_group *se_tpg;
     int ret;
 
     se_tpg = se_sess->se_tpg;
     BUG_ON(!se_tpg);
 
     __target_init_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
               0, DMA_NONE, TCM_SIMPLE_TAG, sense, unpacked_lun);
     /*
      * FIXME: Currently expect caller to handle se_cmd->se_tmr_req
      * allocation failure.
      */
     ret = core_tmr_alloc_req(se_cmd, fabric_tmr_ptr, tm_type, gfp);
     if (ret < 0)
         return -ENOMEM;
 
     if (tm_type == TMR_ABORT_TASK)
         se_cmd->se_tmr_req->ref_task_tag = tag;
 
     /* See target_submit_cmd for commentary */
     ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
     if (ret) {
         core_tmr_release_req(se_cmd->se_tmr_req);
         return ret;
     }
 
     ret = transport_lookup_tmr_lun(se_cmd);
     if (ret)
         goto failure;
 
     transport_generic_handle_tmr(se_cmd);
     return 0;
 
     /*
      * For callback during failure handling, push this work off
      * to process context with TMR_LUN_DOES_NOT_EXIST status.
      */
 failure:
     INIT_WORK(&se_cmd->work, target_complete_tmr_failure);
     schedule_work(&se_cmd->work);
     return 0;
 }
 EXPORT_SYMBOL(target_submit_tmr);
 
 /*
  * Handle SAM-esque emulation for generic transport request failures.
  */
 void transport_generic_request_failure(struct se_cmd *cmd,
         sense_reason_t sense_reason)
 {
     int ret = 0, post_ret;
 
     pr_debug("-----[ Storage Engine Exception; sense_reason %d\n",
          sense_reason);
     target_show_cmd("-----[ ", cmd);
 
     /*
      * For SAM Task Attribute emulation for failed struct se_cmd
      */
     transport_complete_task_attr(cmd);
 
     if (cmd->transport_complete_callback)
         cmd->transport_complete_callback(cmd, false, &post_ret);
 
     if (cmd->transport_state & CMD_T_ABORTED) {
         INIT_WORK(&cmd->work, target_abort_work);
         queue_work(target_completion_wq, &cmd->work);
         return;
     }
 
     switch (sense_reason) {
     case TCM_NON_EXISTENT_LUN:
     case TCM_UNSUPPORTED_SCSI_OPCODE:
     case TCM_INVALID_CDB_FIELD:
     case TCM_INVALID_PARAMETER_LIST:
     case TCM_PARAMETER_LIST_LENGTH_ERROR:
     case TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE:
     case TCM_UNKNOWN_MODE_PAGE:
     case TCM_WRITE_PROTECTED:
     case TCM_ADDRESS_OUT_OF_RANGE:
     case TCM_CHECK_CONDITION_ABORT_CMD:
     case TCM_CHECK_CONDITION_UNIT_ATTENTION:
     case TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED:
     case TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED:
     case TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED:
     case TCM_COPY_TARGET_DEVICE_NOT_REACHABLE:
     case TCM_TOO_MANY_TARGET_DESCS:
     case TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE:
     case TCM_TOO_MANY_SEGMENT_DESCS:
     case TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE:
     case TCM_INVALID_FIELD_IN_COMMAND_IU:
     case TCM_ALUA_TG_PT_STANDBY:
     case TCM_ALUA_TG_PT_UNAVAILABLE:
     case TCM_ALUA_STATE_TRANSITION:
     case TCM_ALUA_OFFLINE:
         break;
     case TCM_OUT_OF_RESOURCES:
         cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
         goto queue_status;
     case TCM_LUN_BUSY:
         cmd->scsi_status = SAM_STAT_BUSY;
         goto queue_status;
     case TCM_RESERVATION_CONFLICT:
         /*
          * No SENSE Data payload for this case, set SCSI Status
          * and queue the response to $FABRIC_MOD.
          *
          * Uses linux/include/scsi/scsi.h SAM status codes defs
          */
         cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
         /*
          * For UA Interlock Code 11b, a RESERVATION CONFLICT will
          * establish a UNIT ATTENTION with PREVIOUS RESERVATION
          * CONFLICT STATUS.
          *
          * See spc4r17, section 7.4.6 Control Mode Page, Table 349
          */
         if (cmd->se_sess &&
             cmd->se_dev->dev_attrib.emulate_ua_intlck_ctrl
                     == TARGET_UA_INTLCK_CTRL_ESTABLISH_UA) {
             target_ua_allocate_lun(cmd->se_sess->se_node_acl,
                            cmd->orig_fe_lun, 0x2C,
                     ASCQ_2CH_PREVIOUS_RESERVATION_CONFLICT_STATUS);
         }
 
         goto queue_status;
     default:
         pr_err("Unknown transport error for CDB 0x%02x: %d\n",
             cmd->t_task_cdb[0], sense_reason);
         sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
         break;
     }
 
     ret = transport_send_check_condition_and_sense(cmd, sense_reason, 0);
     if (ret)
         goto queue_full;
 
 check_stop:
     transport_lun_remove_cmd(cmd);
     transport_cmd_check_stop_to_fabric(cmd);
     return;
 
 queue_status:
     trace_target_cmd_complete(cmd);
     ret = cmd->se_tfo->queue_status(cmd);
     if (!ret)
         goto check_stop;
 queue_full:
     transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
 }
 EXPORT_SYMBOL(transport_generic_request_failure);
 
 void __target_execute_cmd(struct se_cmd *cmd, bool do_checks)
 {
     sense_reason_t ret;
 
     if (!cmd->execute_cmd) {
         ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
         goto err;
     }
     if (do_checks) {
         /*
          * Check for an existing UNIT ATTENTION condition after
          * target_handle_task_attr() has done SAM task attr
          * checking, and possibly have already defered execution
          * out to target_restart_delayed_cmds() context.
          */
         ret = target_scsi3_ua_check(cmd);
         if (ret)
             goto err;
 
         ret = target_alua_state_check(cmd);
         if (ret)
             goto err;
 
         ret = target_check_reservation(cmd);
         if (ret) {
             cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
             goto err;
         }
     }
 
     ret = cmd->execute_cmd(cmd);
     if (!ret)
         return;
 err:
     spin_lock_irq(&cmd->t_state_lock);
     cmd->transport_state &= ~CMD_T_SENT;
     spin_unlock_irq(&cmd->t_state_lock);
 
     transport_generic_request_failure(cmd, ret);
 }
 
 static int target_write_prot_action(struct se_cmd *cmd)
 {
     u32 sectors;
     /*
      * Perform WRITE_INSERT of PI using software emulation when backend
      * device has PI enabled, if the transport has not already generated
      * PI using hardware WRITE_INSERT offload.
      */
     switch (cmd->prot_op) {
     case TARGET_PROT_DOUT_INSERT:
         if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_INSERT))
             sbc_dif_generate(cmd);
         break;
     case TARGET_PROT_DOUT_STRIP:
         if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_STRIP)
             break;
 
         sectors = cmd->data_length >> ilog2(cmd->se_dev->dev_attrib.block_size);
         cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
                          sectors, 0, cmd->t_prot_sg, 0);
         if (unlikely(cmd->pi_err)) {
             spin_lock_irq(&cmd->t_state_lock);
             cmd->transport_state &= ~CMD_T_SENT;
             spin_unlock_irq(&cmd->t_state_lock);
             transport_generic_request_failure(cmd, cmd->pi_err);
             return -1;
         }
         break;
     default:
         break;
     }
 
     return 0;
 }
 
 static bool target_handle_task_attr(struct se_cmd *cmd)
 {
     struct se_device *dev = cmd->se_dev;
 
     if (dev->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
         return false;
 
     cmd->se_cmd_flags |= SCF_TASK_ATTR_SET;
 
     /*
      * Check for the existence of HEAD_OF_QUEUE, and if true return 1
      * to allow the passed struct se_cmd list of tasks to the front of the list.
      */
     switch (cmd->sam_task_attr) {
     case TCM_HEAD_TAG:
         atomic_inc_mb(&dev->non_ordered);
         pr_debug("Added HEAD_OF_QUEUE for CDB: 0x%02x\n",
              cmd->t_task_cdb[0]);
         return false;
     case TCM_ORDERED_TAG:
         atomic_inc_mb(&dev->delayed_cmd_count);
 
         pr_debug("Added ORDERED for CDB: 0x%02x to ordered list\n",
              cmd->t_task_cdb[0]);
         break;
     default:
         /*
          * For SIMPLE and UNTAGGED Task Attribute commands
          */
         atomic_inc_mb(&dev->non_ordered);
 
         if (atomic_read(&dev->delayed_cmd_count) == 0)
             return false;
         break;
     }
 
     if (cmd->sam_task_attr != TCM_ORDERED_TAG) {
         atomic_inc_mb(&dev->delayed_cmd_count);
         /*
          * We will account for this when we dequeue from the delayed
          * list.
          */
         atomic_dec_mb(&dev->non_ordered);
     }
 
     spin_lock_irq(&cmd->t_state_lock);
     cmd->transport_state &= ~CMD_T_SENT;
     spin_unlock_irq(&cmd->t_state_lock);
 
     spin_lock(&dev->delayed_cmd_lock);
     list_add_tail(&cmd->se_delayed_node, &dev->delayed_cmd_list);
     spin_unlock(&dev->delayed_cmd_lock);
 
     pr_debug("Added CDB: 0x%02x Task Attr: 0x%02x to delayed CMD listn",
         cmd->t_task_cdb[0], cmd->sam_task_attr);
     /*
      * We may have no non ordered cmds when this function started or we
      * could have raced with the last simple/head cmd completing, so kick
      * the delayed handler here.
      */
     schedule_work(&dev->delayed_cmd_work);
     return true;
 }
 
 void target_execute_cmd(struct se_cmd *cmd)
 {
     /*
      * Determine if frontend context caller is requesting the stopping of
      * this command for frontend exceptions.
      *
      * If the received CDB has already been aborted stop processing it here.
      */
     if (target_cmd_interrupted(cmd))
         return;
 
     spin_lock_irq(&cmd->t_state_lock);
     cmd->t_state = TRANSPORT_PROCESSING;
     cmd->transport_state |= CMD_T_ACTIVE | CMD_T_SENT;
     spin_unlock_irq(&cmd->t_state_lock);
 
     if (target_write_prot_action(cmd))
         return;
 
     if (target_handle_task_attr(cmd))
         return;
 
     __target_execute_cmd(cmd, true);
 }
 EXPORT_SYMBOL(target_execute_cmd);
 
 /*
  * Process all commands up to the last received ORDERED task attribute which
  * requires another blocking boundary
  */
 void target_do_delayed_work(struct work_struct *work)
 {
     struct se_device *dev = container_of(work, struct se_device,
                          delayed_cmd_work);
 
     spin_lock(&dev->delayed_cmd_lock);
     while (!dev->ordered_sync_in_progress) {
         struct se_cmd *cmd;
 
         if (list_empty(&dev->delayed_cmd_list))
             break;
 
         cmd = list_entry(dev->delayed_cmd_list.next,
                  struct se_cmd, se_delayed_node);
 
         if (cmd->sam_task_attr == TCM_ORDERED_TAG) {
             /*
              * Check if we started with:
              * [ordered] [simple] [ordered]
              * and we are now at the last ordered so we have to wait
              * for the simple cmd.
              */
             if (atomic_read(&dev->non_ordered) > 0)
                 break;
 
             dev->ordered_sync_in_progress = true;
         }
 
         list_del(&cmd->se_delayed_node);
         atomic_dec_mb(&dev->delayed_cmd_count);
         spin_unlock(&dev->delayed_cmd_lock);
 
         if (cmd->sam_task_attr != TCM_ORDERED_TAG)
             atomic_inc_mb(&dev->non_ordered);
 
         cmd->transport_state |= CMD_T_SENT;
 
         __target_execute_cmd(cmd, true);
 
         spin_lock(&dev->delayed_cmd_lock);
     }
     spin_unlock(&dev->delayed_cmd_lock);
 }
 
 /*
  * Called from I/O completion to determine which dormant/delayed
  * and ordered cmds need to have their tasks added to the execution queue.
  */
 static void transport_complete_task_attr(struct se_cmd *cmd)
 {
     struct se_device *dev = cmd->se_dev;
 
     if (dev->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
         return;
 
     if (!(cmd->se_cmd_flags & SCF_TASK_ATTR_SET))
         goto restart;
 
     if (cmd->sam_task_attr == TCM_SIMPLE_TAG) {
         atomic_dec_mb(&dev->non_ordered);
         dev->dev_cur_ordered_id++;
     } else if (cmd->sam_task_attr == TCM_HEAD_TAG) {
         atomic_dec_mb(&dev->non_ordered);
         dev->dev_cur_ordered_id++;
         pr_debug("Incremented dev_cur_ordered_id: %u for HEAD_OF_QUEUE\n",
              dev->dev_cur_ordered_id);
     } else if (cmd->sam_task_attr == TCM_ORDERED_TAG) {
         spin_lock(&dev->delayed_cmd_lock);
         dev->ordered_sync_in_progress = false;
         spin_unlock(&dev->delayed_cmd_lock);
 
         dev->dev_cur_ordered_id++;
         pr_debug("Incremented dev_cur_ordered_id: %u for ORDERED\n",
              dev->dev_cur_ordered_id);
     }
     cmd->se_cmd_flags &= ~SCF_TASK_ATTR_SET;
 
 restart:
     if (atomic_read(&dev->delayed_cmd_count) > 0)
         schedule_work(&dev->delayed_cmd_work);
 }
 
 static void transport_complete_qf(struct se_cmd *cmd)
 {
     int ret = 0;
 
     transport_complete_task_attr(cmd);
     /*
      * If a fabric driver ->write_pending() or ->queue_data_in() callback
      * has returned neither -ENOMEM or -EAGAIN, assume it's fatal and
      * the same callbacks should not be retried.  Return CHECK_CONDITION
      * if a scsi_status is not already set.
      *
      * If a fabric driver ->queue_status() has returned non zero, always
      * keep retrying no matter what..
      */
     if (cmd->t_state == TRANSPORT_COMPLETE_QF_ERR) {
         if (cmd->scsi_status)
             goto queue_status;
 
         translate_sense_reason(cmd, TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
         goto queue_status;
     }
 
     /*
      * Check if we need to send a sense buffer from
      * the struct se_cmd in question. We do NOT want
      * to take this path of the IO has been marked as
      * needing to be treated like a "normal read". This
      * is the case if it's a tape read, and either the
      * FM, EOM, or ILI bits are set, but there is no
      * sense data.
      */
     if (!(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL) &&
         cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
         goto queue_status;
 
     switch (cmd->data_direction) {
     case DMA_FROM_DEVICE:
         /* queue status if not treating this as a normal read */
         if (cmd->scsi_status &&
             !(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL))
             goto queue_status;
 
         trace_target_cmd_complete(cmd);
         ret = cmd->se_tfo->queue_data_in(cmd);
         break;
     case DMA_TO_DEVICE:
         if (cmd->se_cmd_flags & SCF_BIDI) {
             ret = cmd->se_tfo->queue_data_in(cmd);
             break;
         }
         fallthrough;
     case DMA_NONE:
 queue_status:
         trace_target_cmd_complete(cmd);
         ret = cmd->se_tfo->queue_status(cmd);
         break;
     default:
         break;
     }
 
     if (ret < 0) {
         transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
         return;
     }
     transport_lun_remove_cmd(cmd);
     transport_cmd_check_stop_to_fabric(cmd);
 }
 
 static void transport_handle_queue_full(struct se_cmd *cmd, struct se_device *dev,
                     int err, bool write_pending)
 {
     /*
      * -EAGAIN or -ENOMEM signals retry of ->write_pending() and/or
      * ->queue_data_in() callbacks from new process context.
      *
      * Otherwise for other errors, transport_complete_qf() will send
      * CHECK_CONDITION via ->queue_status() instead of attempting to
      * retry associated fabric driver data-transfer callbacks.
      */
     if (err == -EAGAIN || err == -ENOMEM) {
         cmd->t_state = (write_pending) ? TRANSPORT_COMPLETE_QF_WP :
                          TRANSPORT_COMPLETE_QF_OK;
     } else {
         pr_warn_ratelimited("Got unknown fabric queue status: %d\n", err);
         cmd->t_state = TRANSPORT_COMPLETE_QF_ERR;
     }
 
     spin_lock_irq(&dev->qf_cmd_lock);
     list_add_tail(&cmd->se_qf_node, &cmd->se_dev->qf_cmd_list);
     atomic_inc_mb(&dev->dev_qf_count);
     spin_unlock_irq(&cmd->se_dev->qf_cmd_lock);
 
     schedule_work(&cmd->se_dev->qf_work_queue);
 }
 
 static bool target_read_prot_action(struct se_cmd *cmd)
 {
     switch (cmd->prot_op) {
     case TARGET_PROT_DIN_STRIP:
         if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_STRIP)) {
             u32 sectors = cmd->data_length >>
                   ilog2(cmd->se_dev->dev_attrib.block_size);
 
             cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
                              sectors, 0, cmd->t_prot_sg,
                              0);
             if (cmd->pi_err)
                 return true;
         }
         break;
     case TARGET_PROT_DIN_INSERT:
         if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_INSERT)
             break;
 
         sbc_dif_generate(cmd);
         break;
     default:
         break;
     }
 
     return false;
 }
 
 static void target_complete_ok_work(struct work_struct *work)
 {
     struct se_cmd *cmd = container_of(work, struct se_cmd, work);
     int ret;
 
     /*
      * Check if we need to move delayed/dormant tasks from cmds on the
      * delayed execution list after a HEAD_OF_QUEUE or ORDERED Task
      * Attribute.
      */
     transport_complete_task_attr(cmd);
 
     /*
      * Check to schedule QUEUE_FULL work, or execute an existing
      * cmd->transport_qf_callback()
      */
     if (atomic_read(&cmd->se_dev->dev_qf_count) != 0)
         schedule_work(&cmd->se_dev->qf_work_queue);
 
     /*
      * Check if we need to send a sense buffer from
      * the struct se_cmd in question. We do NOT want
      * to take this path of the IO has been marked as
      * needing to be treated like a "normal read". This
      * is the case if it's a tape read, and either the
      * FM, EOM, or ILI bits are set, but there is no
      * sense data.
      */
     if (!(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL) &&
         cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
         WARN_ON(!cmd->scsi_status);
         ret = transport_send_check_condition_and_sense(
                     cmd, 0, 1);
         if (ret)
             goto queue_full;
 
         transport_lun_remove_cmd(cmd);
         transport_cmd_check_stop_to_fabric(cmd);
         return;
     }
     /*
      * Check for a callback, used by amongst other things
      * XDWRITE_READ_10 and COMPARE_AND_WRITE emulation.
      */
     if (cmd->transport_complete_callback) {
         sense_reason_t rc;
         bool caw = (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE);
         bool zero_dl = !(cmd->data_length);
         int post_ret = 0;
 
         rc = cmd->transport_complete_callback(cmd, true, &post_ret);
         if (!rc && !post_ret) {
             if (caw && zero_dl)
                 goto queue_rsp;
 
             return;
         } else if (rc) {
             ret = transport_send_check_condition_and_sense(cmd,
                         rc, 0);
             if (ret)
                 goto queue_full;
 
             transport_lun_remove_cmd(cmd);
             transport_cmd_check_stop_to_fabric(cmd);
             return;
         }
     }
 
 queue_rsp:
     switch (cmd->data_direction) {
     case DMA_FROM_DEVICE:
         /*
          * if this is a READ-type IO, but SCSI status
          * is set, then skip returning data and just
          * return the status -- unless this IO is marked
          * as needing to be treated as a normal read,
          * in which case we want to go ahead and return
          * the data. This happens, for example, for tape
          * reads with the FM, EOM, or ILI bits set, with
          * no sense data.
          */
         if (cmd->scsi_status &&
             !(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL))
             goto queue_status;
 
         atomic_long_add(cmd->data_length,
                 &cmd->se_lun->lun_stats.tx_data_octets);
         /*
          * Perform READ_STRIP of PI using software emulation when
          * backend had PI enabled, if the transport will not be
          * performing hardware READ_STRIP offload.
          */
         if (target_read_prot_action(cmd)) {
             ret = transport_send_check_condition_and_sense(cmd,
                         cmd->pi_err, 0);
             if (ret)
                 goto queue_full;
 
             transport_lun_remove_cmd(cmd);
             transport_cmd_check_stop_to_fabric(cmd);
             return;
         }
 
         trace_target_cmd_complete(cmd);
         ret = cmd->se_tfo->queue_data_in(cmd);
         if (ret)
             goto queue_full;
         break;
     case DMA_TO_DEVICE:
         atomic_long_add(cmd->data_length,
                 &cmd->se_lun->lun_stats.rx_data_octets);
         /*
          * Check if we need to send READ payload for BIDI-COMMAND
          */
         if (cmd->se_cmd_flags & SCF_BIDI) {
             atomic_long_add(cmd->data_length,
                     &cmd->se_lun->lun_stats.tx_data_octets);
             ret = cmd->se_tfo->queue_data_in(cmd);
             if (ret)
                 goto queue_full;
             break;
         }
         fallthrough;
     case DMA_NONE:
 queue_status:
         trace_target_cmd_complete(cmd);
         ret = cmd->se_tfo->queue_status(cmd);
         if (ret)
             goto queue_full;
         break;
     default:
         break;
     }
 
     transport_lun_remove_cmd(cmd);
     transport_cmd_check_stop_to_fabric(cmd);
     return;
 
 queue_full:
     pr_debug("Handling complete_ok QUEUE_FULL: se_cmd: %p,"
         " data_direction: %d\n", cmd, cmd->data_direction);
 
     transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
 }
 
 void target_free_sgl(struct scatterlist *sgl, int nents)
 {
     sgl_free_n_order(sgl, nents, 0);
 }
 EXPORT_SYMBOL(target_free_sgl);
 
 static inline void transport_reset_sgl_orig(struct se_cmd *cmd)
 {
     /*
      * Check for saved t_data_sg that may be used for COMPARE_AND_WRITE
      * emulation, and free + reset pointers if necessary..
      */
     if (!cmd->t_data_sg_orig)
         return;
 
     kfree(cmd->t_data_sg);
     cmd->t_data_sg = cmd->t_data_sg_orig;
     cmd->t_data_sg_orig = NULL;
     cmd->t_data_nents = cmd->t_data_nents_orig;
     cmd->t_data_nents_orig = 0;
 }
 
 static inline void transport_free_pages(struct se_cmd *cmd)
 {
     if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
         target_free_sgl(cmd->t_prot_sg, cmd->t_prot_nents);
         cmd->t_prot_sg = NULL;
         cmd->t_prot_nents = 0;
     }
 
     if (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) {
         /*
          * Release special case READ buffer payload required for
          * SG_TO_MEM_NOALLOC to function with COMPARE_AND_WRITE
          */
         if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
             target_free_sgl(cmd->t_bidi_data_sg,
                        cmd->t_bidi_data_nents);
             cmd->t_bidi_data_sg = NULL;
             cmd->t_bidi_data_nents = 0;
         }
         transport_reset_sgl_orig(cmd);
         return;
     }
     transport_reset_sgl_orig(cmd);
 
     target_free_sgl(cmd->t_data_sg, cmd->t_data_nents);
     cmd->t_data_sg = NULL;
     cmd->t_data_nents = 0;
 
     target_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);
     cmd->t_bidi_data_sg = NULL;
     cmd->t_bidi_data_nents = 0;
 }
 
 void *transport_kmap_data_sg(struct se_cmd *cmd)
 {
     struct scatterlist *sg = cmd->t_data_sg;
     struct page **pages;
     int i;
 
     /*
      * We need to take into account a possible offset here for fabrics like
      * tcm_loop who may be using a contig buffer from the SCSI midlayer for
      * control CDBs passed as SGLs via transport_generic_map_mem_to_cmd()
      */
     if (!cmd->t_data_nents)
         return NULL;
 
     BUG_ON(!sg);
     if (cmd->t_data_nents == 1)
         return kmap(sg_page(sg)) + sg->offset;
 
     /* >1 page. use vmap */
     pages = kmalloc_array(cmd->t_data_nents, sizeof(*pages), GFP_KERNEL);
     if (!pages)
         return NULL;
 
     /* convert sg[] to pages[] */
     for_each_sg(cmd->t_data_sg, sg, cmd->t_data_nents, i) {
         pages[i] = sg_page(sg);
     }
 
     cmd->t_data_vmap = vmap(pages, cmd->t_data_nents,  VM_MAP, PAGE_KERNEL);
     kfree(pages);
     if (!cmd->t_data_vmap)
         return NULL;
 
     return cmd->t_data_vmap + cmd->t_data_sg[0].offset;
 }
 EXPORT_SYMBOL(transport_kmap_data_sg);
 
 void transport_kunmap_data_sg(struct se_cmd *cmd)
 {
     if (!cmd->t_data_nents) {
         return;
     } else if (cmd->t_data_nents == 1) {
         kunmap(sg_page(cmd->t_data_sg));
         return;
     }
 
     vunmap(cmd->t_data_vmap);
     cmd->t_data_vmap = NULL;
 }
 EXPORT_SYMBOL(transport_kunmap_data_sg);
 
 int
 target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents, u32 length,
          bool zero_page, bool chainable)
 {
     gfp_t gfp = GFP_KERNEL | (zero_page ? __GFP_ZERO : 0);
 
     *sgl = sgl_alloc_order(length, 0, chainable, gfp, nents);
     return *sgl ? 0 : -ENOMEM;
 }
 EXPORT_SYMBOL(target_alloc_sgl);
 
 /*
  * Allocate any required resources to execute the command.  For writes we
  * might not have the payload yet, so notify the fabric via a call to
  * ->write_pending instead. Otherwise place it on the execution queue.
  */
 sense_reason_t
 transport_generic_new_cmd(struct se_cmd *cmd)
 {
     unsigned long flags;
     int ret = 0;
     bool zero_flag = !(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB);
 
     if (cmd->prot_op != TARGET_PROT_NORMAL &&
         !(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
         ret = target_alloc_sgl(&cmd->t_prot_sg, &cmd->t_prot_nents,
                        cmd->prot_length, true, false);
         if (ret < 0)
             return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
     }
 
     /*
      * Determine if the TCM fabric module has already allocated physical
      * memory, and is directly calling transport_generic_map_mem_to_cmd()
      * beforehand.
      */
     if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) &&
         cmd->data_length) {
 
         if ((cmd->se_cmd_flags & SCF_BIDI) ||
             (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)) {
             u32 bidi_length;
 
             if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)
                 bidi_length = cmd->t_task_nolb *
                           cmd->se_dev->dev_attrib.block_size;
             else
                 bidi_length = cmd->data_length;
 
             ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
                            &cmd->t_bidi_data_nents,
                            bidi_length, zero_flag, false);
             if (ret < 0)
                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
         }
 
         ret = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,
                        cmd->data_length, zero_flag, false);
         if (ret < 0)
             return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
     } else if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
             cmd->data_length) {
         /*
          * Special case for COMPARE_AND_WRITE with fabrics
          * using SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC.
          */
         u32 caw_length = cmd->t_task_nolb *
                  cmd->se_dev->dev_attrib.block_size;
 
         ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
                        &cmd->t_bidi_data_nents,
                        caw_length, zero_flag, false);
         if (ret < 0)
             return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
     }
     /*
      * If this command is not a write we can execute it right here,
      * for write buffers we need to notify the fabric driver first
      * and let it call back once the write buffers are ready.
      */
     target_add_to_state_list(cmd);
     if (cmd->data_direction != DMA_TO_DEVICE || cmd->data_length == 0) {
         target_execute_cmd(cmd);
         return 0;
     }
 
     spin_lock_irqsave(&cmd->t_state_lock, flags);
     cmd->t_state = TRANSPORT_WRITE_PENDING;
     /*
      * Determine if frontend context caller is requesting the stopping of
      * this command for frontend exceptions.
      */
     if (cmd->transport_state & CMD_T_STOP &&
         !cmd->se_tfo->write_pending_must_be_called) {
         pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
              __func__, __LINE__, cmd->tag);
 
         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 
         complete_all(&cmd->t_transport_stop_comp);
         return 0;
     }
     cmd->transport_state &= ~CMD_T_ACTIVE;
     spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 
     ret = cmd->se_tfo->write_pending(cmd);
     if (ret)
         goto queue_full;
 
     return 0;
 
 queue_full:
     pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n", cmd);
     transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
     return 0;
 }
 EXPORT_SYMBOL(transport_generic_new_cmd);
 
 static void transport_write_pending_qf(struct se_cmd *cmd)
 {
     unsigned long flags;
     int ret;
     bool stop;
 
     spin_lock_irqsave(&cmd->t_state_lock, flags);
     stop = (cmd->transport_state & (CMD_T_STOP | CMD_T_ABORTED));
     spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 
     if (stop) {
         pr_debug("%s:%d CMD_T_STOP|CMD_T_ABORTED for ITT: 0x%08llx\n",
             __func__, __LINE__, cmd->tag);
         complete_all(&cmd->t_transport_stop_comp);
         return;
     }
 
     ret = cmd->se_tfo->write_pending(cmd);
     if (ret) {
         pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n",
              cmd);
         transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
     }
 }
 
 static bool
 __transport_wait_for_tasks(struct se_cmd *, bool, bool *, bool *,
                unsigned long *flags);
 
 static void target_wait_free_cmd(struct se_cmd *cmd, bool *aborted, bool *tas)
 {
     unsigned long flags;
 
     spin_lock_irqsave(&cmd->t_state_lock, flags);
     __transport_wait_for_tasks(cmd, true, aborted, tas, &flags);
     spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 }
 
 /*
  * Call target_put_sess_cmd() and wait until target_release_cmd_kref(@cmd) has
  * finished.
  */
 void target_put_cmd_and_wait(struct se_cmd *cmd)
 {
     DECLARE_COMPLETION_ONSTACK(compl);
 
     WARN_ON_ONCE(cmd->abrt_compl);
     cmd->abrt_compl = &compl;
     target_put_sess_cmd(cmd);
     wait_for_completion(&compl);
 }
 
 /*
  * This function is called by frontend drivers after processing of a command
  * has finished.
  *
  * The protocol for ensuring that either the regular frontend command
  * processing flow or target_handle_abort() code drops one reference is as
  * follows:
  * - Calling .queue_data_in(), .queue_status() or queue_tm_rsp() will cause
  *   the frontend driver to call this function synchronously or asynchronously.
  *   That will cause one reference to be dropped.
  * - During regular command processing the target core sets CMD_T_COMPLETE
  *   before invoking one of the .queue_*() functions.
  * - The code that aborts commands skips commands and TMFs for which
  *   CMD_T_COMPLETE has been set.
  * - CMD_T_ABORTED is set atomically after the CMD_T_COMPLETE check for
  *   commands that will be aborted.
  * - If the CMD_T_ABORTED flag is set but CMD_T_TAS has not been set
  *   transport_generic_free_cmd() skips its call to target_put_sess_cmd().
  * - For aborted commands for which CMD_T_TAS has been set .queue_status() will
  *   be called and will drop a reference.
  * - For aborted commands for which CMD_T_TAS has not been set .aborted_task()
  *   will be called. target_handle_abort() will drop the final reference.
  */
 int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
 {
     DECLARE_COMPLETION_ONSTACK(compl);
     int ret = 0;
     bool aborted = false, tas = false;
 
     if (wait_for_tasks)
         target_wait_free_cmd(cmd, &aborted, &tas);
 
     if (cmd->se_cmd_flags & SCF_SE_LUN_CMD) {
         /*
          * Handle WRITE failure case where transport_generic_new_cmd()
          * has already added se_cmd to state_list, but fabric has
          * failed command before I/O submission.
          */
         if (cmd->state_active)
             target_remove_from_state_list(cmd);
 
         if (cmd->se_lun)
             transport_lun_remove_cmd(cmd);
     }
     if (aborted)
         cmd->free_compl = &compl;
     ret = target_put_sess_cmd(cmd);
     if (aborted) {
         pr_debug("Detected CMD_T_ABORTED for ITT: %llu\n", cmd->tag);
         wait_for_completion(&compl);
         ret = 1;
     }
     return ret;
 }
 EXPORT_SYMBOL(transport_generic_free_cmd);
 
 /**
  * target_get_sess_cmd - Verify the session is accepting cmds and take ref
  * @se_cmd: command descriptor to add
  * @ack_kref:   Signal that fabric will perform an ack target_put_sess_cmd()
  */
 int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
 {
     struct se_session *se_sess = se_cmd->se_sess;
     int ret = 0;
 
     /*
      * Add a second kref if the fabric caller is expecting to handle
      * fabric acknowledgement that requires two target_put_sess_cmd()
      * invocations before se_cmd descriptor release.
      */
     if (ack_kref) {
         kref_get(&se_cmd->cmd_kref);
         se_cmd->se_cmd_flags |= SCF_ACK_KREF;
     }
 
     if (!percpu_ref_tryget_live(&se_sess->cmd_count))
         ret = -ESHUTDOWN;
 
     if (ret && ack_kref)
         target_put_sess_cmd(se_cmd);
 
     return ret;
 }
 EXPORT_SYMBOL(target_get_sess_cmd);
 
 static void target_free_cmd_mem(struct se_cmd *cmd)
 {
     transport_free_pages(cmd);
 
     if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
         core_tmr_release_req(cmd->se_tmr_req);
     if (cmd->t_task_cdb != cmd->__t_task_cdb)
         kfree(cmd->t_task_cdb);
 }
 
 static void target_release_cmd_kref(struct kref *kref)
 {
     struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
     struct se_session *se_sess = se_cmd->se_sess;
     struct completion *free_compl = se_cmd->free_compl;
     struct completion *abrt_compl = se_cmd->abrt_compl;
 
     target_free_cmd_mem(se_cmd);
     se_cmd->se_tfo->release_cmd(se_cmd);
     if (free_compl)
         complete(free_compl);
     if (abrt_compl)
         complete(abrt_compl);
 
     percpu_ref_put(&se_sess->cmd_count);
 }
 
 /**
  * target_put_sess_cmd - decrease the command reference count
  * @se_cmd: command to drop a reference from
  *
  * Returns 1 if and only if this target_put_sess_cmd() call caused the
  * refcount to drop to zero. Returns zero otherwise.
  */
 int target_put_sess_cmd(struct se_cmd *se_cmd)
 {
     return kref_put(&se_cmd->cmd_kref, target_release_cmd_kref);
 }
 EXPORT_SYMBOL(target_put_sess_cmd);
 
 static const char *data_dir_name(enum dma_data_direction d)
 {
     switch (d) {
     case DMA_BIDIRECTIONAL: return "BIDI";
     case DMA_TO_DEVICE: return "WRITE";
     case DMA_FROM_DEVICE:   return "READ";
     case DMA_NONE:      return "NONE";
     }
 
     return "(?)";
 }
 
 static const char *cmd_state_name(enum transport_state_table t)
 {
     switch (t) {
     case TRANSPORT_NO_STATE:    return "NO_STATE";
     case TRANSPORT_NEW_CMD:     return "NEW_CMD";
     case TRANSPORT_WRITE_PENDING:   return "WRITE_PENDING";
     case TRANSPORT_PROCESSING:  return "PROCESSING";
     case TRANSPORT_COMPLETE:    return "COMPLETE";
     case TRANSPORT_ISTATE_PROCESSING:
                     return "ISTATE_PROCESSING";
     case TRANSPORT_COMPLETE_QF_WP:  return "COMPLETE_QF_WP";
     case TRANSPORT_COMPLETE_QF_OK:  return "COMPLETE_QF_OK";
     case TRANSPORT_COMPLETE_QF_ERR: return "COMPLETE_QF_ERR";
     }
 
     return "(?)";
 }
 
 static void target_append_str(char **str, const char *txt)
 {
     char *prev = *str;
 
     *str = *str ? kasprintf(GFP_ATOMIC, "%s,%s", *str, txt) :
         kstrdup(txt, GFP_ATOMIC);
     kfree(prev);
 }
 
 /*
  * Convert a transport state bitmask into a string. The caller is
  * responsible for freeing the returned pointer.
  */
 static char *target_ts_to_str(u32 ts)
 {
     char *str = NULL;
 
     if (ts & CMD_T_ABORTED)
         target_append_str(&str, "aborted");
     if (ts & CMD_T_ACTIVE)
         target_append_str(&str, "active");
     if (ts & CMD_T_COMPLETE)
         target_append_str(&str, "complete");
     if (ts & CMD_T_SENT)
         target_append_str(&str, "sent");
     if (ts & CMD_T_STOP)
         target_append_str(&str, "stop");
     if (ts & CMD_T_FABRIC_STOP)
         target_append_str(&str, "fabric_stop");
 
     return str;
 }
 
 static const char *target_tmf_name(enum tcm_tmreq_table tmf)
 {
     switch (tmf) {
     case TMR_ABORT_TASK:        return "ABORT_TASK";
     case TMR_ABORT_TASK_SET:    return "ABORT_TASK_SET";
     case TMR_CLEAR_ACA:     return "CLEAR_ACA";
     case TMR_CLEAR_TASK_SET:    return "CLEAR_TASK_SET";
     case TMR_LUN_RESET:     return "LUN_RESET";
     case TMR_TARGET_WARM_RESET: return "TARGET_WARM_RESET";
     case TMR_TARGET_COLD_RESET: return "TARGET_COLD_RESET";
     case TMR_LUN_RESET_PRO:     return "LUN_RESET_PRO";
     case TMR_UNKNOWN:       break;
     }
     return "(?)";
 }
 
 void target_show_cmd(const char *pfx, struct se_cmd *cmd)
 {
     char *ts_str = target_ts_to_str(cmd->transport_state);
     const u8 *cdb = cmd->t_task_cdb;
     struct se_tmr_req *tmf = cmd->se_tmr_req;
 
     if (!(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
         pr_debug("%scmd %#02x:%#02x with tag %#llx dir %s i_state %d t_state %s len %d refcnt %d transport_state %s\n",
              pfx, cdb[0], cdb[1], cmd->tag,
              data_dir_name(cmd->data_direction),
              cmd->se_tfo->get_cmd_state(cmd),
              cmd_state_name(cmd->t_state), cmd->data_length,
              kref_read(&cmd->cmd_kref), ts_str);
     } else {
         pr_debug("%stmf %s with tag %#llx ref_task_tag %#llx i_state %d t_state %s refcnt %d transport_state %s\n",
              pfx, target_tmf_name(tmf->function), cmd->tag,
              tmf->ref_task_tag, cmd->se_tfo->get_cmd_state(cmd),
              cmd_state_name(cmd->t_state),
              kref_read(&cmd->cmd_kref), ts_str);
     }
     kfree(ts_str);
 }
 EXPORT_SYMBOL(target_show_cmd);
 
 static void target_stop_session_confirm(struct percpu_ref *ref)
 {
     struct se_session *se_sess = container_of(ref, struct se_session,
                           cmd_count);
     complete_all(&se_sess->stop_done);
 }
 
 /**
  * target_stop_session - Stop new IO from being queued on the session.
  * @se_sess:    session to stop
  */
 void target_stop_session(struct se_session *se_sess)
 {
     pr_debug("Stopping session queue.\n");
     if (atomic_cmpxchg(&se_sess->stopped, 0, 1) == 0)
         percpu_ref_kill_and_confirm(&se_sess->cmd_count,
                         target_stop_session_confirm);
 }
 EXPORT_SYMBOL(target_stop_session);
 
 /**
  * target_wait_for_sess_cmds - Wait for outstanding commands
  * @se_sess:    session to wait for active I/O
  */
 void target_wait_for_sess_cmds(struct se_session *se_sess)
 {
     int ret;
 
     WARN_ON_ONCE(!atomic_read(&se_sess->stopped));
 
     do {
         pr_debug("Waiting for running cmds to complete.\n");
         ret = wait_event_timeout(se_sess->cmd_count_wq,
                 percpu_ref_is_zero(&se_sess->cmd_count),
                 180 * HZ);
     } while (ret <= 0);
 
     wait_for_completion(&se_sess->stop_done);
     pr_debug("Waiting for cmds done.\n");
 }
 EXPORT_SYMBOL(target_wait_for_sess_cmds);
 
 /*
  * Prevent that new percpu_ref_tryget_live() calls succeed and wait until
  * all references to the LUN have been released. Called during LUN shutdown.
  */
 void transport_clear_lun_ref(struct se_lun *lun)
 {
     percpu_ref_kill(&lun->lun_ref);
     wait_for_completion(&lun->lun_shutdown_comp);
 }
 
 static bool
 __transport_wait_for_tasks(struct se_cmd *cmd, bool fabric_stop,
                bool *aborted, bool *tas, unsigned long *flags)
     __releases(&cmd->t_state_lock)
     __acquires(&cmd->t_state_lock)
 {
     lockdep_assert_held(&cmd->t_state_lock);
 
     if (fabric_stop)
         cmd->transport_state |= CMD_T_FABRIC_STOP;
 
     if (cmd->transport_state & CMD_T_ABORTED)
         *aborted = true;
 
     if (cmd->transport_state & CMD_T_TAS)
         *tas = true;
 
     if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) &&
         !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
         return false;
 
     if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) &&
         !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
         return false;
 
     if (!(cmd->transport_state & CMD_T_ACTIVE))
         return false;
 
     if (fabric_stop && *aborted)
         return false;
 
     cmd->transport_state |= CMD_T_STOP;
 
     target_show_cmd("wait_for_tasks: Stopping ", cmd);
 
     spin_unlock_irqrestore(&cmd->t_state_lock, *flags);
 
     while (!wait_for_completion_timeout(&cmd->t_transport_stop_comp,
                         180 * HZ))
         target_show_cmd("wait for tasks: ", cmd);
 
     spin_lock_irqsave(&cmd->t_state_lock, *flags);
     cmd->transport_state &= ~(CMD_T_ACTIVE | CMD_T_STOP);
 
     pr_debug("wait_for_tasks: Stopped wait_for_completion(&cmd->"
          "t_transport_stop_comp) for ITT: 0x%08llx\n", cmd->tag);
 
     return true;
 }
 
 /**
  * transport_wait_for_tasks - set CMD_T_STOP and wait for t_transport_stop_comp
  * @cmd: command to wait on
  */
 bool transport_wait_for_tasks(struct se_cmd *cmd)
 {
     unsigned long flags;
     bool ret, aborted = false, tas = false;
 
     spin_lock_irqsave(&cmd->t_state_lock, flags);
     ret = __transport_wait_for_tasks(cmd, false, &aborted, &tas, &flags);
     spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 
     return ret;
 }
 EXPORT_SYMBOL(transport_wait_for_tasks);
 
 struct sense_detail {
     u8 key;
     u8 asc;
     u8 ascq;
     bool add_sense_info;
 };
 
 static const struct sense_detail sense_detail_table[] = {
     [TCM_NO_SENSE] = {
         .key = NOT_READY
     },
     [TCM_NON_EXISTENT_LUN] = {
         .key = ILLEGAL_REQUEST,
         .asc = 0x25 /* LOGICAL UNIT NOT SUPPORTED */
     },
     [TCM_UNSUPPORTED_SCSI_OPCODE] = {
         .key = ILLEGAL_REQUEST,
         .asc = 0x20, /* INVALID COMMAND OPERATION CODE */
     },
     [TCM_SECTOR_COUNT_TOO_MANY] = {
         .key = ILLEGAL_REQUEST,
         .asc = 0x20, /* INVALID COMMAND OPERATION CODE */
     },
     [TCM_UNKNOWN_MODE_PAGE] = {
         .key = ILLEGAL_REQUEST,
         .asc = 0x24, /* INVALID FIELD IN CDB */
     },
     [TCM_CHECK_CONDITION_ABORT_CMD] = {
         .key = ABORTED_COMMAND,
         .asc = 0x29, /* BUS DEVICE RESET FUNCTION OCCURRED */
         .ascq = 0x03,
     },
     [TCM_INCORRECT_AMOUNT_OF_DATA] = {
         .key = ABORTED_COMMAND,
         .asc = 0x0c, /* WRITE ERROR */
         .ascq = 0x0d, /* NOT ENOUGH UNSOLICITED DATA */
     },
     [TCM_INVALID_CDB_FIELD] = {
         .key = ILLEGAL_REQUEST,
         .asc = 0x24, /* INVALID FIELD IN CDB */
     },
     [TCM_INVALID_PARAMETER_LIST] = {
         .key = ILLEGAL_REQUEST,
         .asc = 0x26, /* INVALID FIELD IN PARAMETER LIST */
     },
     [TCM_TOO_MANY_TARGET_DESCS] = {
         .key = ILLEGAL_REQUEST,
         .asc = 0x26,
         .ascq = 0x06, /* TOO MANY TARGET DESCRIPTORS */
     },
     [TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE] = {
         .key = ILLEGAL_REQUEST,
         .asc = 0x26,
         .ascq = 0x07, /* UNSUPPORTED TARGET DESCRIPTOR TYPE CODE */
     },
     [TCM_TOO_MANY_SEGMENT_DESCS] = {
         .key = ILLEGAL_REQUEST,
         .asc = 0x26,
         .ascq = 0x08, /* TOO MANY SEGMENT DESCRIPTORS */
     },
     [TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE] = {
         .key = ILLEGAL_REQUEST,
         .asc = 0x26,
         .ascq = 0x09, /* UNSUPPORTED SEGMENT DESCRIPTOR TYPE CODE */
     },
     [TCM_PARAMETER_LIST_LENGTH_ERROR] = {
         .key = ILLEGAL_REQUEST,
         .asc = 0x1a, /* PARAMETER LIST LENGTH ERROR */
     },
     [TCM_UNEXPECTED_UNSOLICITED_DATA] = {
         .key = ILLEGAL_REQUEST,
         .asc = 0x0c, /* WRITE ERROR */
         .ascq = 0x0c, /* UNEXPECTED_UNSOLICITED_DATA */
     },
     [TCM_SERVICE_CRC_ERROR] = {
         .key = ABORTED_COMMAND,
         .asc = 0x47, /* PROTOCOL SERVICE CRC ERROR */
         .ascq = 0x05, /* N/A */
     },
     [TCM_SNACK_REJECTED] = {
         .key = ABORTED_COMMAND,
         .asc = 0x11, /* READ ERROR */
         .ascq = 0x13, /* FAILED RETRANSMISSION REQUEST */
     },
     [TCM_WRITE_PROTECTED] = {
         .key = DATA_PROTECT,
         .asc = 0x27, /* WRITE PROTECTED */
     },
     [TCM_ADDRESS_OUT_OF_RANGE] = {
         .key = ILLEGAL_REQUEST,
         .asc = 0x21, /* LOGICAL BLOCK ADDRESS OUT OF RANGE */
     },
     [TCM_CHECK_CONDITION_UNIT_ATTENTION] = {
         .key = UNIT_ATTENTION,
     },
     [TCM_MISCOMPARE_VERIFY] = {
         .key = MISCOMPARE,
         .asc = 0x1d, /* MISCOMPARE DURING VERIFY OPERATION */
         .ascq = 0x00,
         .add_sense_info = true,
     },
     [TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED] = {
         .key = ABORTED_COMMAND,
         .asc = 0x10,
         .ascq = 0x01, /* LOGICAL BLOCK GUARD CHECK FAILED */
         .add_sense_info = true,
     },
     [TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED] = {
         .key = ABORTED_COMMAND,
         .asc = 0x10,
         .ascq = 0x02, /* LOGICAL BLOCK APPLICATION TAG CHECK FAILED */
         .add_sense_info = true,
     },
     [TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED] = {
         .key = ABORTED_COMMAND,
         .asc = 0x10,
         .ascq = 0x03, /* LOGICAL BLOCK REFERENCE TAG CHECK FAILED */
         .add_sense_info = true,
     },
     [TCM_COPY_TARGET_DEVICE_NOT_REACHABLE] = {
         .key = COPY_ABORTED,
         .asc = 0x0d,
         .ascq = 0x02, /* COPY TARGET DEVICE NOT REACHABLE */
 
     },
     [TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE] = {
         /*
          * Returning ILLEGAL REQUEST would cause immediate IO errors on
          * Solaris initiators.  Returning NOT READY instead means the
          * operations will be retried a finite number of times and we
          * can survive intermittent errors.
          */
         .key = NOT_READY,
         .asc = 0x08, /* LOGICAL UNIT COMMUNICATION FAILURE */
     },
     [TCM_INSUFFICIENT_REGISTRATION_RESOURCES] = {
         /*
          * From spc4r22 section5.7.7,5.7.8
          * If a PERSISTENT RESERVE OUT command with a REGISTER service action
          * or a REGISTER AND IGNORE EXISTING KEY service action or
          * REGISTER AND MOVE service actionis attempted,
          * but there are insufficient device server resources to complete the
          * operation, then the command shall be terminated with CHECK CONDITION
          * status, with the sense key set to ILLEGAL REQUEST,and the additonal
          * sense code set to INSUFFICIENT REGISTRATION RESOURCES.
          */
         .key = ILLEGAL_REQUEST,
         .asc = 0x55,
         .ascq = 0x04, /* INSUFFICIENT REGISTRATION RESOURCES */
     },
     [TCM_INVALID_FIELD_IN_COMMAND_IU] = {
         .key = ILLEGAL_REQUEST,
         .asc = 0x0e,
         .ascq = 0x03, /* INVALID FIELD IN COMMAND INFORMATION UNIT */
     },
     [TCM_ALUA_TG_PT_STANDBY] = {
         .key = NOT_READY,
         .asc = 0x04,
         .ascq = ASCQ_04H_ALUA_TG_PT_STANDBY,
     },
     [TCM_ALUA_TG_PT_UNAVAILABLE] = {
         .key = NOT_READY,
         .asc = 0x04,
         .ascq = ASCQ_04H_ALUA_TG_PT_UNAVAILABLE,
     },
     [TCM_ALUA_STATE_TRANSITION] = {
         .key = NOT_READY,
         .asc = 0x04,
         .ascq = ASCQ_04H_ALUA_STATE_TRANSITION,
     },
     [TCM_ALUA_OFFLINE] = {
         .key = NOT_READY,
         .asc = 0x04,
         .ascq = ASCQ_04H_ALUA_OFFLINE,
     },
 };
 
 /**
  * translate_sense_reason - translate a sense reason into T10 key, asc and ascq
  * @cmd: SCSI command in which the resulting sense buffer or SCSI status will
  *   be stored.
  * @reason: LIO sense reason code. If this argument has the value
  *   TCM_CHECK_CONDITION_UNIT_ATTENTION, try to dequeue a unit attention. If
  *   dequeuing a unit attention fails due to multiple commands being processed
  *   concurrently, set the command status to BUSY.
  *
  * Return: 0 upon success or -EINVAL if the sense buffer is too small.
  */
 static void translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason)
 {
     const struct sense_detail *sd;
     u8 *buffer = cmd->sense_buffer;
     int r = (__force int)reason;
     u8 key, asc, ascq;
     bool desc_format = target_sense_desc_format(cmd->se_dev);
 
     if (r < ARRAY_SIZE(sense_detail_table) && sense_detail_table[r].key)
         sd = &sense_detail_table[r];
     else
         sd = &sense_detail_table[(__force int)
                        TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE];
 
     key = sd->key;
     if (reason == TCM_CHECK_CONDITION_UNIT_ATTENTION) {
         if (!core_scsi3_ua_for_check_condition(cmd, &key, &asc,
                                &ascq)) {
             cmd->scsi_status = SAM_STAT_BUSY;
             return;
         }
     } else {
         WARN_ON_ONCE(sd->asc == 0);
         asc = sd->asc;
         ascq = sd->ascq;
     }
 
     cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
     cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
     cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
     scsi_build_sense_buffer(desc_format, buffer, key, asc, ascq);
     if (sd->add_sense_info)
         WARN_ON_ONCE(scsi_set_sense_information(buffer,
                             cmd->scsi_sense_length,
                             cmd->sense_info) < 0);
 }
 
 int
 transport_send_check_condition_and_sense(struct se_cmd *cmd,
         sense_reason_t reason, int from_transport)
 {
     unsigned long flags;
 
     WARN_ON_ONCE(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB);
 
     spin_lock_irqsave(&cmd->t_state_lock, flags);
     if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
         return 0;
     }
     cmd->se_cmd_flags |= SCF_SENT_CHECK_CONDITION;
     spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 
     if (!from_transport)
         translate_sense_reason(cmd, reason);
 
     trace_target_cmd_complete(cmd);
     return cmd->se_tfo->queue_status(cmd);
 }
 EXPORT_SYMBOL(transport_send_check_condition_and_sense);
 
 /**
  * target_send_busy - Send SCSI BUSY status back to the initiator
  * @cmd: SCSI command for which to send a BUSY reply.
  *
  * Note: Only call this function if target_submit_cmd*() failed.
  */
 int target_send_busy(struct se_cmd *cmd)
 {
     WARN_ON_ONCE(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB);
 
     cmd->scsi_status = SAM_STAT_BUSY;
     trace_target_cmd_complete(cmd);
     return cmd->se_tfo->queue_status(cmd);
 }
 EXPORT_SYMBOL(target_send_busy);
 
 static void target_tmr_work(struct work_struct *work)
 {
     struct se_cmd *cmd = container_of(work, struct se_cmd, work);
     struct se_device *dev = cmd->se_dev;
     struct se_tmr_req *tmr = cmd->se_tmr_req;
     int ret;
 
     if (cmd->transport_state & CMD_T_ABORTED)
         goto aborted;
 
     switch (tmr->function) {
     case TMR_ABORT_TASK:
         core_tmr_abort_task(dev, tmr, cmd->se_sess);
         break;
     case TMR_ABORT_TASK_SET:
     case TMR_CLEAR_ACA:
     case TMR_CLEAR_TASK_SET:
         tmr->response = TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
         break;
     case TMR_LUN_RESET:
         ret = core_tmr_lun_reset(dev, tmr, NULL, NULL);
         tmr->response = (!ret) ? TMR_FUNCTION_COMPLETE :
                      TMR_FUNCTION_REJECTED;
         if (tmr->response == TMR_FUNCTION_COMPLETE) {
             target_ua_allocate_lun(cmd->se_sess->se_node_acl,
                            cmd->orig_fe_lun, 0x29,
                            ASCQ_29H_BUS_DEVICE_RESET_FUNCTION_OCCURRED);
         }
         break;
     case TMR_TARGET_WARM_RESET:
         tmr->response = TMR_FUNCTION_REJECTED;
         break;
     case TMR_TARGET_COLD_RESET:
         tmr->response = TMR_FUNCTION_REJECTED;
         break;
     default:
         pr_err("Unknown TMR function: 0x%02x.\n",
                 tmr->function);
         tmr->response = TMR_FUNCTION_REJECTED;
         break;
     }
 
     if (cmd->transport_state & CMD_T_ABORTED)
         goto aborted;
 
     cmd->se_tfo->queue_tm_rsp(cmd);
 
     transport_lun_remove_cmd(cmd);
     transport_cmd_check_stop_to_fabric(cmd);
     return;
 
 aborted:
     target_handle_abort(cmd);
 }
 
 int transport_generic_handle_tmr(
     struct se_cmd *cmd)
 {
     unsigned long flags;
     bool aborted = false;
 
     spin_lock_irqsave(&cmd->t_state_lock, flags);
     if (cmd->transport_state & CMD_T_ABORTED) {
         aborted = true;
     } else {
         cmd->t_state = TRANSPORT_ISTATE_PROCESSING;
         cmd->transport_state |= CMD_T_ACTIVE;
     }
     spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 
     if (aborted) {
         pr_warn_ratelimited("handle_tmr caught CMD_T_ABORTED TMR %d ref_tag: %llu tag: %llu\n",
                     cmd->se_tmr_req->function,
                     cmd->se_tmr_req->ref_task_tag, cmd->tag);
         target_handle_abort(cmd);
         return 0;
     }
 
     INIT_WORK(&cmd->work, target_tmr_work);
     schedule_work(&cmd->work);
     return 0;
 }
 EXPORT_SYMBOL(transport_generic_handle_tmr);
 
 bool
 target_check_wce(struct se_device *dev)
 {
     bool wce = false;
 
     if (dev->transport->get_write_cache)
         wce = dev->transport->get_write_cache(dev);
     else if (dev->dev_attrib.emulate_write_cache > 0)
         wce = true;
 
     return wce;
 }
 
 bool
 target_check_fua(struct se_device *dev)
 {
     return target_check_wce(dev) && dev->dev_attrib.emulate_fua_write > 0;
 }