Quelle  target_core_device.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later
/*******************************************************************************
 * Filename:  target_core_device.c (based on iscsi_target_device.c)
 *
 * This file contains the TCM Virtual Device and Disk Transport
 * agnostic related functions.
 *
 * (c) Copyright 2003-2013 Datera, Inc.
 *
 * Nicholas A. Bellinger <nab@kernel.org>
 *
 ******************************************************************************/

#include <linux/net.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/timer.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/kthread.h>
#include <linux/in.h>
#include <linux/export.h>
#include <linux/t10-pi.h>
#include <linux/unaligned.h>
#include <net/sock.h>
#include <net/tcp.h>
#include <scsi/scsi_common.h>
#include <scsi/scsi_proto.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"

static DEFINE_MUTEX(device_mutex);
static DEFINE_IDR(devices_idr);

static struct se_hba *lun0_hba;
/* not static, needed by tpg.c */
struct se_device *g_lun0_dev;

sense_reason_t
transport_lookup_cmd_lun(struct se_cmd *se_cmd)
{
 struct se_lun *se_lun = NULL;
 struct se_session *se_sess = se_cmd->se_sess;
 struct se_node_acl *nacl = se_sess->se_node_acl;
 struct se_dev_entry *deve;
 sense_reason_t ret = TCM_NO_SENSE;

 rcu_read_lock();
 deve = target_nacl_find_deve(nacl, se_cmd->orig_fe_lun);
 if (deve) {
  this_cpu_inc(deve->stats->total_cmds);

  if (se_cmd->data_direction == DMA_TO_DEVICE)
   this_cpu_add(deve->stats->write_bytes,
         se_cmd->data_length);
  else if (se_cmd->data_direction == DMA_FROM_DEVICE)
   this_cpu_add(deve->stats->read_bytes,
         se_cmd->data_length);

  if ((se_cmd->data_direction == DMA_TO_DEVICE) &&
      deve->lun_access_ro) {
   pr_err("TARGET_CORE[%s]: Detected WRITE_PROTECTED LUN"
    " Access for 0x%08llx\n",
    se_cmd->se_tfo->fabric_name,
    se_cmd->orig_fe_lun);
   rcu_read_unlock();
   return TCM_WRITE_PROTECTED;
  }

  se_lun = deve->se_lun;

  if (!percpu_ref_tryget_live(&se_lun->lun_ref)) {
   se_lun = NULL;
   goto out_unlock;
  }

  se_cmd->se_lun = se_lun;
  se_cmd->pr_res_key = deve->pr_res_key;
  se_cmd->se_cmd_flags |= SCF_SE_LUN_CMD;
  se_cmd->lun_ref_active = true;
 }
out_unlock:
 rcu_read_unlock();

 if (!se_lun) {
  /*
 * Use the se_portal_group->tpg_virt_lun0 to allow for
 * REPORT_LUNS, et al to be returned when no active
 * MappedLUN=0 exists for this Initiator Port.
 */
  if (se_cmd->orig_fe_lun != 0) {
   pr_err("TARGET_CORE[%s]: Detected NON_EXISTENT_LUN"
    " Access for 0x%08llx from %s\n",
    se_cmd->se_tfo->fabric_name,
    se_cmd->orig_fe_lun,
    nacl->initiatorname);
   return TCM_NON_EXISTENT_LUN;
  }

  /*
 * Force WRITE PROTECT for virtual LUN 0
 */
  if ((se_cmd->data_direction != DMA_FROM_DEVICE) &&
      (se_cmd->data_direction != DMA_NONE))
   return TCM_WRITE_PROTECTED;

  se_lun = se_sess->se_tpg->tpg_virt_lun0;
  if (!percpu_ref_tryget_live(&se_lun->lun_ref))
   return TCM_NON_EXISTENT_LUN;

  se_cmd->se_lun = se_sess->se_tpg->tpg_virt_lun0;
  se_cmd->se_cmd_flags |= SCF_SE_LUN_CMD;
  se_cmd->lun_ref_active = true;
 }
 /*
 * RCU reference protected by percpu se_lun->lun_ref taken above that
 * must drop to zero (including initial reference) before this se_lun
 * pointer can be kfree_rcu() by the final se_lun->lun_group put via
 * target_core_fabric_configfs.c:target_fabric_port_release
 */
 se_cmd->se_dev = rcu_dereference_raw(se_lun->lun_se_dev);
 this_cpu_inc(se_cmd->se_dev->stats->total_cmds);

 if (se_cmd->data_direction == DMA_TO_DEVICE)
  this_cpu_add(se_cmd->se_dev->stats->write_bytes,
        se_cmd->data_length);
 else if (se_cmd->data_direction == DMA_FROM_DEVICE)
  this_cpu_add(se_cmd->se_dev->stats->read_bytes,
        se_cmd->data_length);

 return ret;
}
EXPORT_SYMBOL(transport_lookup_cmd_lun);

int transport_lookup_tmr_lun(struct se_cmd *se_cmd)
{
 struct se_dev_entry *deve;
 struct se_lun *se_lun = NULL;
 struct se_session *se_sess = se_cmd->se_sess;
 struct se_node_acl *nacl = se_sess->se_node_acl;
 struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;

 rcu_read_lock();
 deve = target_nacl_find_deve(nacl, se_cmd->orig_fe_lun);
 if (deve) {
  se_lun = deve->se_lun;

  if (!percpu_ref_tryget_live(&se_lun->lun_ref)) {
   se_lun = NULL;
   goto out_unlock;
  }

  se_cmd->se_lun = se_lun;
  se_cmd->pr_res_key = deve->pr_res_key;
  se_cmd->se_cmd_flags |= SCF_SE_LUN_CMD;
  se_cmd->lun_ref_active = true;
 }
out_unlock:
 rcu_read_unlock();

 if (!se_lun) {
  pr_debug("TARGET_CORE[%s]: Detected NON_EXISTENT_LUN"
   " Access for 0x%08llx for %s\n",
   se_cmd->se_tfo->fabric_name,
   se_cmd->orig_fe_lun,
   nacl->initiatorname);
  return -ENODEV;
 }
 se_cmd->se_dev = rcu_dereference_raw(se_lun->lun_se_dev);
 se_tmr->tmr_dev = rcu_dereference_raw(se_lun->lun_se_dev);

 return 0;
}
EXPORT_SYMBOL(transport_lookup_tmr_lun);

bool target_lun_is_rdonly(struct se_cmd *cmd)
{
 struct se_session *se_sess = cmd->se_sess;
 struct se_dev_entry *deve;
 bool ret;

 rcu_read_lock();
 deve = target_nacl_find_deve(se_sess->se_node_acl, cmd->orig_fe_lun);
 ret = deve && deve->lun_access_ro;
 rcu_read_unlock();

 return ret;
}
EXPORT_SYMBOL(target_lun_is_rdonly);

/*
 * This function is called from core_scsi3_emulate_pro_register_and_move()
 * and core_scsi3_decode_spec_i_port(), and will increment &deve->pr_kref
 * when a matching rtpi is found.
 */
struct se_dev_entry *core_get_se_deve_from_rtpi(
 struct se_node_acl *nacl,
 u16 rtpi)
{
 struct se_dev_entry *deve;
 struct se_lun *lun;
 struct se_portal_group *tpg = nacl->se_tpg;

 rcu_read_lock();
 hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link) {
  lun = deve->se_lun;
  if (!lun) {
   pr_err("%s device entries device pointer is"
    " NULL, but Initiator has access.\n",
    tpg->se_tpg_tfo->fabric_name);
   continue;
  }
  if (lun->lun_tpg->tpg_rtpi != rtpi)
   continue;

  kref_get(&deve->pr_kref);
  rcu_read_unlock();

  return deve;
 }
 rcu_read_unlock();

 return NULL;
}

void core_free_device_list_for_node(
 struct se_node_acl *nacl,
 struct se_portal_group *tpg)
{
 struct se_dev_entry *deve;

 mutex_lock(&nacl->lun_entry_mutex);
 hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link)
  core_disable_device_list_for_node(deve->se_lun, deve, nacl, tpg);
 mutex_unlock(&nacl->lun_entry_mutex);
}

void core_update_device_list_access(
 u64 mapped_lun,
 bool lun_access_ro,
 struct se_node_acl *nacl)
{
 struct se_dev_entry *deve;

 mutex_lock(&nacl->lun_entry_mutex);
 deve = target_nacl_find_deve(nacl, mapped_lun);
 if (deve)
  deve->lun_access_ro = lun_access_ro;
 mutex_unlock(&nacl->lun_entry_mutex);
}

/*
 * Called with rcu_read_lock or nacl->device_list_lock held.
 */
struct se_dev_entry *target_nacl_find_deve(struct se_node_acl *nacl, u64 mapped_lun)
{
 struct se_dev_entry *deve;

 hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link)
  if (deve->mapped_lun == mapped_lun)
   return deve;

 return NULL;
}
EXPORT_SYMBOL(target_nacl_find_deve);

void target_pr_kref_release(struct kref *kref)
{
 struct se_dev_entry *deve = container_of(kref, struct se_dev_entry,
       pr_kref);
 complete(&deve->pr_comp);
}

/*
 * Establish UA condition on SCSI device - all LUNs
 */
void target_dev_ua_allocate(struct se_device *dev, u8 asc, u8 ascq)
{
 struct se_dev_entry *se_deve;
 struct se_lun *lun;

 spin_lock(&dev->se_port_lock);
 list_for_each_entry(lun, &dev->dev_sep_list, lun_dev_link) {

  spin_lock(&lun->lun_deve_lock);
  list_for_each_entry(se_deve, &lun->lun_deve_list, lun_link)
   core_scsi3_ua_allocate(se_deve, asc, ascq);
  spin_unlock(&lun->lun_deve_lock);
 }
 spin_unlock(&dev->se_port_lock);
}

static void
target_luns_data_has_changed(struct se_node_acl *nacl, struct se_dev_entry *new,
        bool skip_new)
{
 struct se_dev_entry *tmp;

 rcu_read_lock();
 hlist_for_each_entry_rcu(tmp, &nacl->lun_entry_hlist, link) {
  if (skip_new && tmp == new)
   continue;
  core_scsi3_ua_allocate(tmp, 0x3F,
           ASCQ_3FH_REPORTED_LUNS_DATA_HAS_CHANGED);
 }
 rcu_read_unlock();
}

int core_enable_device_list_for_node(
 struct se_lun *lun,
 struct se_lun_acl *lun_acl,
 u64 mapped_lun,
 bool lun_access_ro,
 struct se_node_acl *nacl,
 struct se_portal_group *tpg)
{
 struct se_dev_entry *orig, *new;
 int ret = 0;

 new = kzalloc(sizeof(*new), GFP_KERNEL);
 if (!new) {
  pr_err("Unable to allocate se_dev_entry memory\n");
  return -ENOMEM;
 }

 new->stats = alloc_percpu(struct se_dev_entry_io_stats);
 if (!new->stats) {
  ret = -ENOMEM;
  goto free_deve;
 }

 spin_lock_init(&new->ua_lock);
 INIT_LIST_HEAD(&new->ua_list);
 INIT_LIST_HEAD(&new->lun_link);

 new->mapped_lun = mapped_lun;
 kref_init(&new->pr_kref);
 init_completion(&new->pr_comp);

 new->lun_access_ro = lun_access_ro;
 new->creation_time = get_jiffies_64();
 new->attach_count++;

 mutex_lock(&nacl->lun_entry_mutex);
 orig = target_nacl_find_deve(nacl, mapped_lun);
 if (orig && orig->se_lun) {
  struct se_lun *orig_lun = orig->se_lun;

  if (orig_lun != lun) {
   pr_err("Existing orig->se_lun doesn't match new lun"
          " for dynamic -> explicit NodeACL conversion:"
    " %s\n", nacl->initiatorname);
   mutex_unlock(&nacl->lun_entry_mutex);
   ret = -EINVAL;
   goto free_stats;
  }
  if (orig->se_lun_acl != NULL) {
   pr_warn_ratelimited("Detected existing explicit"
    " se_lun_acl->se_lun_group reference for %s"
    " mapped_lun: %llu, failing\n",
     nacl->initiatorname, mapped_lun);
   mutex_unlock(&nacl->lun_entry_mutex);
   ret = -EINVAL;
   goto free_stats;
  }

  new->se_lun = lun;
  new->se_lun_acl = lun_acl;
  hlist_del_rcu(&orig->link);
  hlist_add_head_rcu(&new->link, &nacl->lun_entry_hlist);
  mutex_unlock(&nacl->lun_entry_mutex);

  spin_lock(&lun->lun_deve_lock);
  list_del(&orig->lun_link);
  list_add_tail(&new->lun_link, &lun->lun_deve_list);
  spin_unlock(&lun->lun_deve_lock);

  kref_put(&orig->pr_kref, target_pr_kref_release);
  wait_for_completion(&orig->pr_comp);

  target_luns_data_has_changed(nacl, new, true);
  kfree_rcu(orig, rcu_head);
  return 0;
 }

 new->se_lun = lun;
 new->se_lun_acl = lun_acl;
 hlist_add_head_rcu(&new->link, &nacl->lun_entry_hlist);
 mutex_unlock(&nacl->lun_entry_mutex);

 spin_lock(&lun->lun_deve_lock);
 list_add_tail(&new->lun_link, &lun->lun_deve_list);
 spin_unlock(&lun->lun_deve_lock);

 target_luns_data_has_changed(nacl, new, true);
 return 0;

free_stats:
 free_percpu(new->stats);
free_deve:
 kfree(new);
 return ret;
}

static void target_free_dev_entry(struct rcu_head *head)
{
 struct se_dev_entry *deve = container_of(head, struct se_dev_entry,
       rcu_head);
 free_percpu(deve->stats);
 kfree(deve);
}

void core_disable_device_list_for_node(
 struct se_lun *lun,
 struct se_dev_entry *orig,
 struct se_node_acl *nacl,
 struct se_portal_group *tpg)
{
 /*
 * rcu_dereference_raw protected by se_lun->lun_group symlink
 * reference to se_device->dev_group.
 */
 struct se_device *dev = rcu_dereference_raw(lun->lun_se_dev);

 lockdep_assert_held(&nacl->lun_entry_mutex);

 /*
 * If the MappedLUN entry is being disabled, the entry in
 * lun->lun_deve_list must be removed now before clearing the
 * struct se_dev_entry pointers below as logic in
 * core_alua_do_transition_tg_pt() depends on these being present.
 *
 * deve->se_lun_acl will be NULL for demo-mode created LUNs
 * that have not been explicitly converted to MappedLUNs ->
 * struct se_lun_acl, but we remove deve->lun_link from
 * lun->lun_deve_list. This also means that active UAs and
 * NodeACL context specific PR metadata for demo-mode
 * MappedLUN *deve will be released below..
 */
 spin_lock(&lun->lun_deve_lock);
 list_del(&orig->lun_link);
 spin_unlock(&lun->lun_deve_lock);
 /*
 * Disable struct se_dev_entry LUN ACL mapping
 */
 core_scsi3_ua_release_all(orig);

 hlist_del_rcu(&orig->link);
 clear_bit(DEF_PR_REG_ACTIVE, &orig->deve_flags);
 orig->lun_access_ro = false;
 orig->creation_time = 0;
 orig->attach_count--;
 /*
 * Before firing off RCU callback, wait for any in process SPEC_I_PT=1
 * or REGISTER_AND_MOVE PR operation to complete.
 */
 kref_put(&orig->pr_kref, target_pr_kref_release);
 wait_for_completion(&orig->pr_comp);

 call_rcu(&orig->rcu_head, target_free_dev_entry);

 core_scsi3_free_pr_reg_from_nacl(dev, nacl);
 target_luns_data_has_changed(nacl, NULL, false);
}

/*      core_clear_lun_from_tpg():
 *
 *
 */
void core_clear_lun_from_tpg(struct se_lun *lun, struct se_portal_group *tpg)
{
 struct se_node_acl *nacl;
 struct se_dev_entry *deve;

 mutex_lock(&tpg->acl_node_mutex);
 list_for_each_entry(nacl, &tpg->acl_node_list, acl_list) {

  mutex_lock(&nacl->lun_entry_mutex);
  hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link) {
   if (lun != deve->se_lun)
    continue;

   core_disable_device_list_for_node(lun, deve, nacl, tpg);
  }
  mutex_unlock(&nacl->lun_entry_mutex);
 }
 mutex_unlock(&tpg->acl_node_mutex);
}

static void se_release_vpd_for_dev(struct se_device *dev)
{
 struct t10_vpd *vpd, *vpd_tmp;

 spin_lock(&dev->t10_wwn.t10_vpd_lock);
 list_for_each_entry_safe(vpd, vpd_tmp,
   &dev->t10_wwn.t10_vpd_list, vpd_list) {
  list_del(&vpd->vpd_list);
  kfree(vpd);
 }
 spin_unlock(&dev->t10_wwn.t10_vpd_lock);
}

static u32 se_dev_align_max_sectors(u32 max_sectors, u32 block_size)
{
 u32 aligned_max_sectors;
 u32 alignment;
 /*
 * Limit max_sectors to a PAGE_SIZE aligned value for modern
 * transport_allocate_data_tasks() operation.
 */
 alignment = max(1ul, PAGE_SIZE / block_size);
 aligned_max_sectors = rounddown(max_sectors, alignment);

 if (max_sectors != aligned_max_sectors)
  pr_info("Rounding down aligned max_sectors from %u to %u\n",
   max_sectors, aligned_max_sectors);

 return aligned_max_sectors;
}

int core_dev_add_lun(
 struct se_portal_group *tpg,
 struct se_device *dev,
 struct se_lun *lun)
{
 int rc;

 rc = core_tpg_add_lun(tpg, lun, false, dev);
 if (rc < 0)
  return rc;

 pr_debug("%s_TPG[%u]_LUN[%llu] - Activated %s Logical Unit from"
  " CORE HBA: %u\n", tpg->se_tpg_tfo->fabric_name,
  tpg->se_tpg_tfo->tpg_get_tag(tpg), lun->unpacked_lun,
  tpg->se_tpg_tfo->fabric_name, dev->se_hba->hba_id);
 /*
 * Update LUN maps for dynamically added initiators when
 * generate_node_acl is enabled.
 */
 if (tpg->se_tpg_tfo->tpg_check_demo_mode(tpg)) {
  struct se_node_acl *acl;

  mutex_lock(&tpg->acl_node_mutex);
  list_for_each_entry(acl, &tpg->acl_node_list, acl_list) {
   if (acl->dynamic_node_acl &&
       (!tpg->se_tpg_tfo->tpg_check_demo_mode_login_only ||
        !tpg->se_tpg_tfo->tpg_check_demo_mode_login_only(tpg))) {
    core_tpg_add_node_to_devs(acl, tpg, lun);
   }
  }
  mutex_unlock(&tpg->acl_node_mutex);
 }

 return 0;
}

/*      core_dev_del_lun():
 *
 *
 */
void core_dev_del_lun(
 struct se_portal_group *tpg,
 struct se_lun *lun)
{
 pr_debug("%s_TPG[%u]_LUN[%llu] - Deactivating %s Logical Unit from"
  " device object\n", tpg->se_tpg_tfo->fabric_name,
  tpg->se_tpg_tfo->tpg_get_tag(tpg), lun->unpacked_lun,
  tpg->se_tpg_tfo->fabric_name);

 core_tpg_remove_lun(tpg, lun);
}

struct se_lun_acl *core_dev_init_initiator_node_lun_acl(
 struct se_portal_group *tpg,
 struct se_node_acl *nacl,
 u64 mapped_lun,
 int *ret)
{
 struct se_lun_acl *lacl;

 if (strlen(nacl->initiatorname) >= TRANSPORT_IQN_LEN) {
  pr_err("%s InitiatorName exceeds maximum size.\n",
   tpg->se_tpg_tfo->fabric_name);
  *ret = -EOVERFLOW;
  return NULL;
 }
 lacl = kzalloc(sizeof(struct se_lun_acl), GFP_KERNEL);
 if (!lacl) {
  pr_err("Unable to allocate memory for struct se_lun_acl.\n");
  *ret = -ENOMEM;
  return NULL;
 }

 lacl->mapped_lun = mapped_lun;
 lacl->se_lun_nacl = nacl;

 return lacl;
}

int core_dev_add_initiator_node_lun_acl(
 struct se_portal_group *tpg,
 struct se_lun_acl *lacl,
 struct se_lun *lun,
 bool lun_access_ro)
{
 struct se_node_acl *nacl = lacl->se_lun_nacl;
 /*
 * rcu_dereference_raw protected by se_lun->lun_group symlink
 * reference to se_device->dev_group.
 */
 struct se_device *dev = rcu_dereference_raw(lun->lun_se_dev);

 if (!nacl)
  return -EINVAL;

 if (lun->lun_access_ro)
  lun_access_ro = true;

 lacl->se_lun = lun;

 if (core_enable_device_list_for_node(lun, lacl, lacl->mapped_lun,
   lun_access_ro, nacl, tpg) < 0)
  return -EINVAL;

 pr_debug("%s_TPG[%hu]_LUN[%llu->%llu] - Added %s ACL for "
  " InitiatorNode: %s\n", tpg->se_tpg_tfo->fabric_name,
  tpg->se_tpg_tfo->tpg_get_tag(tpg), lun->unpacked_lun, lacl->mapped_lun,
  lun_access_ro ? "RO" : "RW",
  nacl->initiatorname);
 /*
 * Check to see if there are any existing persistent reservation APTPL
 * pre-registrations that need to be enabled for this LUN ACL..
 */
 core_scsi3_check_aptpl_registration(dev, tpg, lun, nacl,
         lacl->mapped_lun);
 return 0;
}

int core_dev_del_initiator_node_lun_acl(
 struct se_lun *lun,
 struct se_lun_acl *lacl)
{
 struct se_portal_group *tpg = lun->lun_tpg;
 struct se_node_acl *nacl;
 struct se_dev_entry *deve;

 nacl = lacl->se_lun_nacl;
 if (!nacl)
  return -EINVAL;

 mutex_lock(&nacl->lun_entry_mutex);
 deve = target_nacl_find_deve(nacl, lacl->mapped_lun);
 if (deve)
  core_disable_device_list_for_node(lun, deve, nacl, tpg);
 mutex_unlock(&nacl->lun_entry_mutex);

 pr_debug("%s_TPG[%hu]_LUN[%llu] - Removed ACL for"
  " InitiatorNode: %s Mapped LUN: %llu\n",
  tpg->se_tpg_tfo->fabric_name,
  tpg->se_tpg_tfo->tpg_get_tag(tpg), lun->unpacked_lun,
  nacl->initiatorname, lacl->mapped_lun);

 return 0;
}

void core_dev_free_initiator_node_lun_acl(
 struct se_portal_group *tpg,
 struct se_lun_acl *lacl)
{
 pr_debug("%s_TPG[%hu] - Freeing ACL for %s InitiatorNode: %s"
  " Mapped LUN: %llu\n", tpg->se_tpg_tfo->fabric_name,
  tpg->se_tpg_tfo->tpg_get_tag(tpg),
  tpg->se_tpg_tfo->fabric_name,
  lacl->se_lun_nacl->initiatorname, lacl->mapped_lun);

 kfree(lacl);
}

static void scsi_dump_inquiry(struct se_device *dev)
{
 struct t10_wwn *wwn = &dev->t10_wwn;
 int device_type = dev->transport->get_device_type(dev);

 /*
 * Print Linux/SCSI style INQUIRY formatting to the kernel ring buffer
 */
 pr_debug(" Vendor: %-" __stringify(INQUIRY_VENDOR_LEN) "s\n",
  wwn->vendor);
 pr_debug(" Model: %-" __stringify(INQUIRY_MODEL_LEN) "s\n",
  wwn->model);
 pr_debug(" Revision: %-" __stringify(INQUIRY_REVISION_LEN) "s\n",
  wwn->revision);
 pr_debug(" Type: %s ", scsi_device_type(device_type));
}

static void target_non_ordered_release(struct percpu_ref *ref)
{
 struct se_device *dev = container_of(ref, struct se_device,
          non_ordered);
 unsigned long flags;

 spin_lock_irqsave(&dev->delayed_cmd_lock, flags);
 if (!list_empty(&dev->delayed_cmd_list))
  schedule_work(&dev->delayed_cmd_work);
 spin_unlock_irqrestore(&dev->delayed_cmd_lock, flags);
}

struct se_device *target_alloc_device(struct se_hba *hba, const char *name)
{
 struct se_device *dev;
 struct se_lun *xcopy_lun;
 int i;

 dev = hba->backend->ops->alloc_device(hba, name);
 if (!dev)
  return NULL;

 dev->stats = alloc_percpu(struct se_dev_io_stats);
 if (!dev->stats)
  goto free_device;

 dev->queues = kcalloc(nr_cpu_ids, sizeof(*dev->queues), GFP_KERNEL);
 if (!dev->queues)
  goto free_stats;

 dev->queue_cnt = nr_cpu_ids;
 for (i = 0; i < dev->queue_cnt; i++) {
  struct se_device_queue *q;

  q = &dev->queues[i];
  INIT_LIST_HEAD(&q->state_list);
  spin_lock_init(&q->lock);

  init_llist_head(&q->sq.cmd_list);
  INIT_WORK(&q->sq.work, target_queued_submit_work);
 }

 if (percpu_ref_init(&dev->non_ordered, target_non_ordered_release,
       PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
  goto free_queues;

 dev->se_hba = hba;
 dev->transport = hba->backend->ops;
 dev->transport_flags = dev->transport->transport_flags_default;
 dev->prot_length = sizeof(struct t10_pi_tuple);
 dev->hba_index = hba->hba_index;

 INIT_LIST_HEAD(&dev->dev_sep_list);
 INIT_LIST_HEAD(&dev->dev_tmr_list);
 INIT_LIST_HEAD(&dev->delayed_cmd_list);
 INIT_LIST_HEAD(&dev->qf_cmd_list);
 spin_lock_init(&dev->delayed_cmd_lock);
 spin_lock_init(&dev->dev_reservation_lock);
 spin_lock_init(&dev->se_port_lock);
 spin_lock_init(&dev->se_tmr_lock);
 spin_lock_init(&dev->qf_cmd_lock);
 sema_init(&dev->caw_sem, 1);
 INIT_LIST_HEAD(&dev->t10_wwn.t10_vpd_list);
 spin_lock_init(&dev->t10_wwn.t10_vpd_lock);
 INIT_LIST_HEAD(&dev->t10_pr.registration_list);
 INIT_LIST_HEAD(&dev->t10_pr.aptpl_reg_list);
 spin_lock_init(&dev->t10_pr.registration_lock);
 spin_lock_init(&dev->t10_pr.aptpl_reg_lock);
 INIT_LIST_HEAD(&dev->t10_alua.tg_pt_gps_list);
 spin_lock_init(&dev->t10_alua.tg_pt_gps_lock);
 INIT_LIST_HEAD(&dev->t10_alua.lba_map_list);
 spin_lock_init(&dev->t10_alua.lba_map_lock);

 INIT_WORK(&dev->delayed_cmd_work, target_do_delayed_work);
 mutex_init(&dev->lun_reset_mutex);

 dev->t10_wwn.t10_dev = dev;
 /*
 * Use OpenFabrics IEEE Company ID: 00 14 05
 */
 dev->t10_wwn.company_id = 0x001405;

 dev->t10_alua.t10_dev = dev;

 dev->dev_attrib.da_dev = dev;
 dev->dev_attrib.emulate_model_alias = DA_EMULATE_MODEL_ALIAS;
 dev->dev_attrib.emulate_dpo = 1;
 dev->dev_attrib.emulate_fua_write = 1;
 dev->dev_attrib.emulate_fua_read = 1;
 dev->dev_attrib.emulate_write_cache = DA_EMULATE_WRITE_CACHE;
 dev->dev_attrib.emulate_ua_intlck_ctrl = TARGET_UA_INTLCK_CTRL_CLEAR;
 dev->dev_attrib.emulate_tas = DA_EMULATE_TAS;
 dev->dev_attrib.emulate_tpu = DA_EMULATE_TPU;
 dev->dev_attrib.emulate_tpws = DA_EMULATE_TPWS;
 dev->dev_attrib.emulate_caw = DA_EMULATE_CAW;
 dev->dev_attrib.emulate_3pc = DA_EMULATE_3PC;
 dev->dev_attrib.emulate_pr = DA_EMULATE_PR;
 dev->dev_attrib.emulate_rsoc = DA_EMULATE_RSOC;
 dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE0_PROT;
 dev->dev_attrib.enforce_pr_isids = DA_ENFORCE_PR_ISIDS;
 dev->dev_attrib.force_pr_aptpl = DA_FORCE_PR_APTPL;
 dev->dev_attrib.is_nonrot = DA_IS_NONROT;
 dev->dev_attrib.emulate_rest_reord = DA_EMULATE_REST_REORD;
 dev->dev_attrib.max_unmap_lba_count = DA_MAX_UNMAP_LBA_COUNT;
 dev->dev_attrib.max_unmap_block_desc_count =
  DA_MAX_UNMAP_BLOCK_DESC_COUNT;
 dev->dev_attrib.unmap_granularity = DA_UNMAP_GRANULARITY_DEFAULT;
 dev->dev_attrib.unmap_granularity_alignment =
    DA_UNMAP_GRANULARITY_ALIGNMENT_DEFAULT;
 dev->dev_attrib.unmap_zeroes_data =
    DA_UNMAP_ZEROES_DATA_DEFAULT;
 dev->dev_attrib.max_write_same_len = DA_MAX_WRITE_SAME_LEN;
 dev->dev_attrib.submit_type = TARGET_FABRIC_DEFAULT_SUBMIT;

 xcopy_lun = &dev->xcopy_lun;
 rcu_assign_pointer(xcopy_lun->lun_se_dev, dev);
 init_completion(&xcopy_lun->lun_shutdown_comp);
 INIT_LIST_HEAD(&xcopy_lun->lun_deve_list);
 INIT_LIST_HEAD(&xcopy_lun->lun_dev_link);
 mutex_init(&xcopy_lun->lun_tg_pt_md_mutex);
 xcopy_lun->lun_tpg = &xcopy_pt_tpg;

 /* Preload the default INQUIRY const values */
 strscpy(dev->t10_wwn.vendor, "LIO-ORG", sizeof(dev->t10_wwn.vendor));
 strscpy(dev->t10_wwn.model, dev->transport->inquiry_prod,
  sizeof(dev->t10_wwn.model));
 strscpy(dev->t10_wwn.revision, dev->transport->inquiry_rev,
  sizeof(dev->t10_wwn.revision));

 return dev;

free_queues:
 kfree(dev->queues);
free_stats:
 free_percpu(dev->stats);
free_device:
 hba->backend->ops->free_device(dev);
 return NULL;
}

/*
 * Check if the underlying struct block_device supports discard and if yes
 * configure the UNMAP parameters.
 */
bool target_configure_unmap_from_queue(struct se_dev_attrib *attrib,
           struct block_device *bdev)
{
 int block_size = bdev_logical_block_size(bdev);

 if (!bdev_max_discard_sectors(bdev))
  return false;

 attrib->max_unmap_lba_count =
  bdev_max_discard_sectors(bdev) >> (ilog2(block_size) - 9);
 /*
 * Currently hardcoded to 1 in Linux/SCSI code..
 */
 attrib->max_unmap_block_desc_count = 1;
 attrib->unmap_granularity = bdev_discard_granularity(bdev) / block_size;
 attrib->unmap_granularity_alignment =
  bdev_discard_alignment(bdev) / block_size;
 return true;
}
EXPORT_SYMBOL(target_configure_unmap_from_queue);

/*
 * Convert from blocksize advertised to the initiator to the 512 byte
 * units unconditionally used by the Linux block layer.
 */
sector_t target_to_linux_sector(struct se_device *dev, sector_t lb)
{
 switch (dev->dev_attrib.block_size) {
 case 4096:
  return lb << 3;
 case 2048:
  return lb << 2;
 case 1024:
  return lb << 1;
 default:
  return lb;
 }
}
EXPORT_SYMBOL(target_to_linux_sector);

struct devices_idr_iter {
 int (*fn)(struct se_device *dev, void *data);
 void *data;
};

static int target_devices_idr_iter(int id, void *p, void *data)
  __must_hold(&device_mutex)
{
 struct devices_idr_iter *iter = data;
 struct se_device *dev = p;
 struct config_item *item;
 int ret;

 /*
 * We add the device early to the idr, so it can be used
 * by backend modules during configuration. We do not want
 * to allow other callers to access partially setup devices,
 * so we skip them here.
 */
 if (!target_dev_configured(dev))
  return 0;

 item = config_item_get_unless_zero(&dev->dev_group.cg_item);
 if (!item)
  return 0;
 mutex_unlock(&device_mutex);

 ret = iter->fn(dev, iter->data);
 config_item_put(item);

 mutex_lock(&device_mutex);
 return ret;
}

/**
 * target_for_each_device - iterate over configured devices
 * @fn: iterator function
 * @data: pointer to data that will be passed to fn
 *
 * fn must return 0 to continue looping over devices. non-zero will break
 * from the loop and return that value to the caller.
 */
int target_for_each_device(int (*fn)(struct se_device *dev, void *data),
      void *data)
{
 struct devices_idr_iter iter = { .fn = fn, .data = data };
 int ret;

 mutex_lock(&device_mutex);
 ret = idr_for_each(&devices_idr, target_devices_idr_iter, &iter);
 mutex_unlock(&device_mutex);
 return ret;
}

int target_configure_device(struct se_device *dev)
{
 struct se_hba *hba = dev->se_hba;
 int ret, id;

 if (target_dev_configured(dev)) {
  pr_err("se_dev->se_dev_ptr already set for storage"
    " object\n");
  return -EEXIST;
 }

 /*
 * Add early so modules like tcmu can use during its
 * configuration.
 */
 mutex_lock(&device_mutex);
 /*
 * Use cyclic to try and avoid collisions with devices
 * that were recently removed.
 */
 id = idr_alloc_cyclic(&devices_idr, dev, 0, INT_MAX, GFP_KERNEL);
 mutex_unlock(&device_mutex);
 if (id < 0) {
  ret = -ENOMEM;
  goto out;
 }
 dev->dev_index = id;

 ret = dev->transport->configure_device(dev);
 if (ret)
  goto out_free_index;

 if (dev->transport->configure_unmap &&
     dev->transport->configure_unmap(dev)) {
  pr_debug("Discard support available, but disabled by default.\n");
 }

 /*
 * XXX: there is not much point to have two different values here..
 */
 dev->dev_attrib.block_size = dev->dev_attrib.hw_block_size;
 dev->dev_attrib.queue_depth = dev->dev_attrib.hw_queue_depth;

 /*
 * Align max_hw_sectors down to PAGE_SIZE I/O transfers
 */
 dev->dev_attrib.hw_max_sectors =
  se_dev_align_max_sectors(dev->dev_attrib.hw_max_sectors,
      dev->dev_attrib.hw_block_size);
 dev->dev_attrib.optimal_sectors = dev->dev_attrib.hw_max_sectors;

 dev->creation_time = get_jiffies_64();

 ret = core_setup_alua(dev);
 if (ret)
  goto out_destroy_device;

 /*
 * Setup work_queue for QUEUE_FULL
 */
 INIT_WORK(&dev->qf_work_queue, target_qf_do_work);

 scsi_dump_inquiry(dev);

 spin_lock(&hba->device_lock);
 hba->dev_count++;
 spin_unlock(&hba->device_lock);

 dev->dev_flags |= DF_CONFIGURED;

 return 0;

out_destroy_device:
 dev->transport->destroy_device(dev);
out_free_index:
 mutex_lock(&device_mutex);
 idr_remove(&devices_idr, dev->dev_index);
 mutex_unlock(&device_mutex);
out:
 se_release_vpd_for_dev(dev);
 return ret;
}

void target_free_device(struct se_device *dev)
{
 struct se_hba *hba = dev->se_hba;

 WARN_ON(!list_empty(&dev->dev_sep_list));

 percpu_ref_exit(&dev->non_ordered);
 cancel_work_sync(&dev->delayed_cmd_work);

 if (target_dev_configured(dev)) {
  dev->transport->destroy_device(dev);

  mutex_lock(&device_mutex);
  idr_remove(&devices_idr, dev->dev_index);
  mutex_unlock(&device_mutex);

  spin_lock(&hba->device_lock);
  hba->dev_count--;
  spin_unlock(&hba->device_lock);
 }

 core_alua_free_lu_gp_mem(dev);
 core_alua_set_lba_map(dev, NULL, 0, 0);
 core_scsi3_free_all_registrations(dev);
 se_release_vpd_for_dev(dev);

 if (dev->transport->free_prot)
  dev->transport->free_prot(dev);

 kfree(dev->queues);
 free_percpu(dev->stats);
 dev->transport->free_device(dev);
}

int core_dev_setup_virtual_lun0(void)
{
 struct se_hba *hba;
 struct se_device *dev;
 char buf[] = "rd_pages=8,rd_nullio=1,rd_dummy=1";
 int ret;

 hba = core_alloc_hba("rd_mcp", 0, HBA_FLAGS_INTERNAL_USE);
 if (IS_ERR(hba))
  return PTR_ERR(hba);

 dev = target_alloc_device(hba, "virt_lun0");
 if (!dev) {
  ret = -ENOMEM;
  goto out_free_hba;
 }

 hba->backend->ops->set_configfs_dev_params(dev, buf, sizeof(buf));

 ret = target_configure_device(dev);
 if (ret)
  goto out_free_se_dev;

 lun0_hba = hba;
 g_lun0_dev = dev;
 return 0;

out_free_se_dev:
 target_free_device(dev);
out_free_hba:
 core_delete_hba(hba);
 return ret;
}


void core_dev_release_virtual_lun0(void)
{
 struct se_hba *hba = lun0_hba;

 if (!hba)
  return;

 if (g_lun0_dev)
  target_free_device(g_lun0_dev);
 core_delete_hba(hba);
}

/*
 * Common CDB parsing for kernel and user passthrough.
 */
sense_reason_t
passthrough_parse_cdb(struct se_cmd *cmd,
 sense_reason_t (*exec_cmd)(struct se_cmd *cmd))
{
 unsigned char *cdb = cmd->t_task_cdb;
 struct se_device *dev = cmd->se_dev;
 unsigned int size;

 /*
 * For REPORT LUNS we always need to emulate the response, for everything
 * else, pass it up.
 */
 if (cdb[0] == REPORT_LUNS) {
  cmd->execute_cmd = spc_emulate_report_luns;
  return TCM_NO_SENSE;
 }

 /*
 * With emulate_pr disabled, all reservation requests should fail,
 * regardless of whether or not TRANSPORT_FLAG_PASSTHROUGH_PGR is set.
 */
 if (!dev->dev_attrib.emulate_pr &&
     ((cdb[0] == PERSISTENT_RESERVE_IN) ||
      (cdb[0] == PERSISTENT_RESERVE_OUT) ||
      (cdb[0] == RELEASE_6 || cdb[0] == RELEASE_10) ||
      (cdb[0] == RESERVE_6 || cdb[0] == RESERVE_10))) {
  return TCM_UNSUPPORTED_SCSI_OPCODE;
 }

 /*
 * For PERSISTENT RESERVE IN/OUT, RELEASE, and RESERVE we need to
 * emulate the response, since tcmu does not have the information
 * required to process these commands.
 */
 if (!(dev->transport_flags &
       TRANSPORT_FLAG_PASSTHROUGH_PGR)) {
  if (cdb[0] == PERSISTENT_RESERVE_IN) {
   cmd->execute_cmd = target_scsi3_emulate_pr_in;
   size = get_unaligned_be16(&cdb[7]);
   return target_cmd_size_check(cmd, size);
  }
  if (cdb[0] == PERSISTENT_RESERVE_OUT) {
   cmd->execute_cmd = target_scsi3_emulate_pr_out;
   size = get_unaligned_be32(&cdb[5]);
   return target_cmd_size_check(cmd, size);
  }

  if (cdb[0] == RELEASE_6 || cdb[0] == RELEASE_10) {
   cmd->execute_cmd = target_scsi2_reservation_release;
   if (cdb[0] == RELEASE_10)
    size = get_unaligned_be16(&cdb[7]);
   else
    size = cmd->data_length;
   return target_cmd_size_check(cmd, size);
  }
  if (cdb[0] == RESERVE_6 || cdb[0] == RESERVE_10) {
   cmd->execute_cmd = target_scsi2_reservation_reserve;
   if (cdb[0] == RESERVE_10)
    size = get_unaligned_be16(&cdb[7]);
   else
    size = cmd->data_length;
   return target_cmd_size_check(cmd, size);
  }
 }

 /* Set DATA_CDB flag for ops that should have it */
 switch (cdb[0]) {
 case READ_6:
 case READ_10:
 case READ_12:
 case READ_16:
 case WRITE_6:
 case WRITE_10:
 case WRITE_12:
 case WRITE_16:
 case WRITE_VERIFY:
 case WRITE_VERIFY_12:
 case WRITE_VERIFY_16:
 case COMPARE_AND_WRITE:
 case XDWRITEREAD_10:
  cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
  break;
 case VARIABLE_LENGTH_CMD:
  switch (get_unaligned_be16(&cdb[8])) {
  case READ_32:
  case WRITE_32:
  case WRITE_VERIFY_32:
  case XDWRITEREAD_32:
   cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
   break;
  }
 }

 cmd->execute_cmd = exec_cmd;

 return TCM_NO_SENSE;
}
EXPORT_SYMBOL(passthrough_parse_cdb);