Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending

Pull SCSI target updates from Nicholas Bellinger:
 "Things have been quiet this round with mostly bugfixes, percpu
  conversions, and other minor iscsi-target conformance testing changes.

  The highlights include:

   - Add demo_mode_discovery attribute for iscsi-target (Thomas)
   - Convert tcm_fc(FCoE) to use percpu-ida pre-allocation
   - Add send completion interrupt coalescing for ib_isert
   - Convert target-core to use percpu-refcounting for se_lun
   - Fix mutex_trylock usage bug in iscsit_increment_maxcmdsn
   - tcm_loop updates (Hannes)
   - target-core ALUA cleanups + prep for v3.14 SCSI Referrals support (Hannes)

  v3.14 is currently shaping to be a busy development cycle in target
  land, with initial support for T10 Referrals and T10 DIF currently on
  the roadmap"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (40 commits)
  iscsi-target: chap auth shouldn't match username with trailing garbage
  iscsi-target: fix extract_param to handle buffer length corner case
  iscsi-target: Expose default_erl as TPG attribute
  target_core_configfs: split up ALUA supported states
  target_core_alua: Make supported states configurable
  target_core_alua: Store supported ALUA states
  target_core_alua: Rename ALUA_ACCESS_STATE_OPTIMIZED
  target_core_alua: spellcheck
  target core: rename (ex,im)plict -> (ex,im)plicit
  percpu-refcount: Add percpu-refcount.o to obj-y
  iscsi-target: Do not reject non-immediate CmdSNs exceeding MaxCmdSN
  iscsi-target: Convert iscsi_session statistics to atomic_long_t
  target: Convert se_device statistics to atomic_long_t
  target: Fix delayed Task Aborted Status (TAS) handling bug
  iscsi-target: Reject unsupported multi PDU text command sequence
  ib_isert: Avoid duplicate iscsit_increment_maxcmdsn call
  iscsi-target: Fix mutex_trylock usage in iscsit_increment_maxcmdsn
  target: Core does not need blkdev.h
  target: Pass through I/O topology for block backstores
  iser-target: Avoid using FRMR for single dma entry requests
  ...

1 files changed, 14 insertions, 230 deletions

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 81e945eefbbd..91953da0f623 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -28,7 +28,6 @@
 #include <linux/string.h>
 #include <linux/timer.h>
 #include <linux/slab.h>
-#include <linux/blkdev.h>
 #include <linux/spinlock.h>
 #include <linux/kthread.h>
 #include <linux/in.h>
@@ -473,7 +472,7 @@ void transport_deregister_session(struct se_session *se_sess)
 	pr_debug("TARGET_CORE[%s]: Deregistered fabric_sess\n",
 		se_tpg->se_tpg_tfo->get_fabric_name());
 	/*
-	 * If last kref is dropping now for an explict NodeACL, awake sleeping
+	 * 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.
 	 */
@@ -515,23 +514,6 @@ static int transport_cmd_check_stop(struct se_cmd *cmd, bool remove_from_lists,
 	if (write_pending)
 		cmd->t_state = TRANSPORT_WRITE_PENDING;
 
-	/*
-	 * Determine if IOCTL context caller in requesting the stopping of this
-	 * command for LUN shutdown purposes.
-	 */
-	if (cmd->transport_state & CMD_T_LUN_STOP) {
-		pr_debug("%s:%d CMD_T_LUN_STOP for ITT: 0x%08x\n",
-			__func__, __LINE__, cmd->se_tfo->get_task_tag(cmd));
-
-		cmd->transport_state &= ~CMD_T_ACTIVE;
-		if (remove_from_lists)
-			target_remove_from_state_list(cmd);
-		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
-
-		complete(&cmd->transport_lun_stop_comp);
-		return 1;
-	}
-
 	if (remove_from_lists) {
 		target_remove_from_state_list(cmd);
 
@@ -585,15 +567,11 @@ static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
 static void transport_lun_remove_cmd(struct se_cmd *cmd)
 {
 	struct se_lun *lun = cmd->se_lun;
-	unsigned long flags;
 
-	if (!lun)
+	if (!lun || !cmd->lun_ref_active)
 		return;
 
-	spin_lock_irqsave(&lun->lun_cmd_lock, flags);
-	if (!list_empty(&cmd->se_lun_node))
-		list_del_init(&cmd->se_lun_node);
-	spin_unlock_irqrestore(&lun->lun_cmd_lock, flags);
+	percpu_ref_put(&lun->lun_ref);
 }
 
 void transport_cmd_finish_abort(struct se_cmd *cmd, int remove)
@@ -668,7 +646,7 @@ void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
 		cmd->transport_state |= CMD_T_FAILED;
 
 	/*
-	 * Check for case where an explict ABORT_TASK has been received
+	 * Check for case where an explicit ABORT_TASK has been received
 	 * and transport_wait_for_tasks() will be waiting for completion..
 	 */
 	if (cmd->transport_state & CMD_T_ABORTED &&
@@ -1092,13 +1070,10 @@ void transport_init_se_cmd(
 	int task_attr,
 	unsigned char *sense_buffer)
 {
-	INIT_LIST_HEAD(&cmd->se_lun_node);
 	INIT_LIST_HEAD(&cmd->se_delayed_node);
 	INIT_LIST_HEAD(&cmd->se_qf_node);
 	INIT_LIST_HEAD(&cmd->se_cmd_list);
 	INIT_LIST_HEAD(&cmd->state_list);
-	init_completion(&cmd->transport_lun_fe_stop_comp);
-	init_completion(&cmd->transport_lun_stop_comp);
 	init_completion(&cmd->t_transport_stop_comp);
 	init_completion(&cmd->cmd_wait_comp);
 	init_completion(&cmd->task_stop_comp);
@@ -1719,29 +1694,14 @@ void target_execute_cmd(struct se_cmd *cmd)
 	/*
 	 * If the received CDB has aleady been aborted stop processing it here.
 	 */
-	if (transport_check_aborted_status(cmd, 1)) {
-		complete(&cmd->transport_lun_stop_comp);
+	if (transport_check_aborted_status(cmd, 1))
 		return;
-	}
 
 	/*
-	 * Determine if IOCTL context caller in requesting the stopping of this
-	 * command for LUN shutdown purposes.
-	 */
-	spin_lock_irq(&cmd->t_state_lock);
-	if (cmd->transport_state & CMD_T_LUN_STOP) {
-		pr_debug("%s:%d CMD_T_LUN_STOP for ITT: 0x%08x\n",
-			__func__, __LINE__, cmd->se_tfo->get_task_tag(cmd));
-
-		cmd->transport_state &= ~CMD_T_ACTIVE;
-		spin_unlock_irq(&cmd->t_state_lock);
-		complete(&cmd->transport_lun_stop_comp);
-		return;
-	}
-	/*
 	 * Determine if frontend context caller is requesting the stopping of
 	 * this command for frontend exceptions.
 	 */
+	spin_lock_irq(&cmd->t_state_lock);
 	if (cmd->transport_state & CMD_T_STOP) {
 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08x\n",
 			__func__, __LINE__,
@@ -2404,164 +2364,23 @@ void target_wait_for_sess_cmds(struct se_session *se_sess)
 }
 EXPORT_SYMBOL(target_wait_for_sess_cmds);
 
-/*	transport_lun_wait_for_tasks():
- *
- *	Called from ConfigFS context to stop the passed struct se_cmd to allow
- *	an struct se_lun to be successfully shutdown.
- */
-static int transport_lun_wait_for_tasks(struct se_cmd *cmd, struct se_lun *lun)
-{
-	unsigned long flags;
-	int ret = 0;
-
-	/*
-	 * If the frontend has already requested this struct se_cmd to
-	 * be stopped, we can safely ignore this struct se_cmd.
-	 */
-	spin_lock_irqsave(&cmd->t_state_lock, flags);
-	if (cmd->transport_state & CMD_T_STOP) {
-		cmd->transport_state &= ~CMD_T_LUN_STOP;
-
-		pr_debug("ConfigFS ITT[0x%08x] - CMD_T_STOP, skipping\n",
-			 cmd->se_tfo->get_task_tag(cmd));
-		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
-		transport_cmd_check_stop(cmd, false, false);
-		return -EPERM;
-	}
-	cmd->transport_state |= CMD_T_LUN_FE_STOP;
-	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
-
-	// XXX: audit task_flags checks.
-	spin_lock_irqsave(&cmd->t_state_lock, flags);
-	if ((cmd->transport_state & CMD_T_BUSY) &&
-	    (cmd->transport_state & CMD_T_SENT)) {
-		if (!target_stop_cmd(cmd, &flags))
-			ret++;
-	}
-	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
-
-	pr_debug("ConfigFS: cmd: %p stop tasks ret:"
-			" %d\n", cmd, ret);
-	if (!ret) {
-		pr_debug("ConfigFS: ITT[0x%08x] - stopping cmd....\n",
-				cmd->se_tfo->get_task_tag(cmd));
-		wait_for_completion(&cmd->transport_lun_stop_comp);
-		pr_debug("ConfigFS: ITT[0x%08x] - stopped cmd....\n",
-				cmd->se_tfo->get_task_tag(cmd));
-	}
-
-	return 0;
-}
-
-static void __transport_clear_lun_from_sessions(struct se_lun *lun)
-{
-	struct se_cmd *cmd = NULL;
-	unsigned long lun_flags, cmd_flags;
-	/*
-	 * Do exception processing and return CHECK_CONDITION status to the
-	 * Initiator Port.
-	 */
-	spin_lock_irqsave(&lun->lun_cmd_lock, lun_flags);
-	while (!list_empty(&lun->lun_cmd_list)) {
-		cmd = list_first_entry(&lun->lun_cmd_list,
-		       struct se_cmd, se_lun_node);
-		list_del_init(&cmd->se_lun_node);
-
-		spin_lock(&cmd->t_state_lock);
-		pr_debug("SE_LUN[%d] - Setting cmd->transport"
-			"_lun_stop for  ITT: 0x%08x\n",
-			cmd->se_lun->unpacked_lun,
-			cmd->se_tfo->get_task_tag(cmd));
-		cmd->transport_state |= CMD_T_LUN_STOP;
-		spin_unlock(&cmd->t_state_lock);
-
-		spin_unlock_irqrestore(&lun->lun_cmd_lock, lun_flags);
-
-		if (!cmd->se_lun) {
-			pr_err("ITT: 0x%08x, [i,t]_state: %u/%u\n",
-				cmd->se_tfo->get_task_tag(cmd),
-				cmd->se_tfo->get_cmd_state(cmd), cmd->t_state);
-			BUG();
-		}
-		/*
-		 * If the Storage engine still owns the iscsi_cmd_t, determine
-		 * and/or stop its context.
-		 */
-		pr_debug("SE_LUN[%d] - ITT: 0x%08x before transport"
-			"_lun_wait_for_tasks()\n", cmd->se_lun->unpacked_lun,
-			cmd->se_tfo->get_task_tag(cmd));
-
-		if (transport_lun_wait_for_tasks(cmd, cmd->se_lun) < 0) {
-			spin_lock_irqsave(&lun->lun_cmd_lock, lun_flags);
-			continue;
-		}
-
-		pr_debug("SE_LUN[%d] - ITT: 0x%08x after transport_lun"
-			"_wait_for_tasks(): SUCCESS\n",
-			cmd->se_lun->unpacked_lun,
-			cmd->se_tfo->get_task_tag(cmd));
-
-		spin_lock_irqsave(&cmd->t_state_lock, cmd_flags);
-		if (!(cmd->transport_state & CMD_T_DEV_ACTIVE)) {
-			spin_unlock_irqrestore(&cmd->t_state_lock, cmd_flags);
-			goto check_cond;
-		}
-		cmd->transport_state &= ~CMD_T_DEV_ACTIVE;
-		target_remove_from_state_list(cmd);
-		spin_unlock_irqrestore(&cmd->t_state_lock, cmd_flags);
-
-		/*
-		 * The Storage engine stopped this struct se_cmd before it was
-		 * send to the fabric frontend for delivery back to the
-		 * Initiator Node.  Return this SCSI CDB back with an
-		 * CHECK_CONDITION status.
-		 */
-check_cond:
-		transport_send_check_condition_and_sense(cmd,
-				TCM_NON_EXISTENT_LUN, 0);
-		/*
-		 *  If the fabric frontend is waiting for this iscsi_cmd_t to
-		 * be released, notify the waiting thread now that LU has
-		 * finished accessing it.
-		 */
-		spin_lock_irqsave(&cmd->t_state_lock, cmd_flags);
-		if (cmd->transport_state & CMD_T_LUN_FE_STOP) {
-			pr_debug("SE_LUN[%d] - Detected FE stop for"
-				" struct se_cmd: %p ITT: 0x%08x\n",
-				lun->unpacked_lun,
-				cmd, cmd->se_tfo->get_task_tag(cmd));
-
-			spin_unlock_irqrestore(&cmd->t_state_lock,
-					cmd_flags);
-			transport_cmd_check_stop(cmd, false, false);
-			complete(&cmd->transport_lun_fe_stop_comp);
-			spin_lock_irqsave(&lun->lun_cmd_lock, lun_flags);
-			continue;
-		}
-		pr_debug("SE_LUN[%d] - ITT: 0x%08x finished processing\n",
-			lun->unpacked_lun, cmd->se_tfo->get_task_tag(cmd));
-
-		spin_unlock_irqrestore(&cmd->t_state_lock, cmd_flags);
-		spin_lock_irqsave(&lun->lun_cmd_lock, lun_flags);
-	}
-	spin_unlock_irqrestore(&lun->lun_cmd_lock, lun_flags);
-}
-
-static int transport_clear_lun_thread(void *p)
+static int transport_clear_lun_ref_thread(void *p)
 {
 	struct se_lun *lun = p;
 
-	__transport_clear_lun_from_sessions(lun);
+	percpu_ref_kill(&lun->lun_ref);
+
+	wait_for_completion(&lun->lun_ref_comp);
 	complete(&lun->lun_shutdown_comp);
 
 	return 0;
 }
 
-int transport_clear_lun_from_sessions(struct se_lun *lun)
+int transport_clear_lun_ref(struct se_lun *lun)
 {
 	struct task_struct *kt;
 
-	kt = kthread_run(transport_clear_lun_thread, lun,
+	kt = kthread_run(transport_clear_lun_ref_thread, lun,
 			"tcm_cl_%u", lun->unpacked_lun);
 	if (IS_ERR(kt)) {
 		pr_err("Unable to start clear_lun thread\n");
@@ -2595,43 +2414,6 @@ bool transport_wait_for_tasks(struct se_cmd *cmd)
 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 		return false;
 	}
-	/*
-	 * If we are already stopped due to an external event (ie: LUN shutdown)
-	 * sleep until the connection can have the passed struct se_cmd back.
-	 * The cmd->transport_lun_stopped_sem will be upped by
-	 * transport_clear_lun_from_sessions() once the ConfigFS context caller
-	 * has completed its operation on the struct se_cmd.
-	 */
-	if (cmd->transport_state & CMD_T_LUN_STOP) {
-		pr_debug("wait_for_tasks: Stopping"
-			" wait_for_completion(&cmd->t_tasktransport_lun_fe"
-			"_stop_comp); for ITT: 0x%08x\n",
-			cmd->se_tfo->get_task_tag(cmd));
-		/*
-		 * There is a special case for WRITES where a FE exception +
-		 * LUN shutdown means ConfigFS context is still sleeping on
-		 * transport_lun_stop_comp in transport_lun_wait_for_tasks().
-		 * We go ahead and up transport_lun_stop_comp just to be sure
-		 * here.
-		 */
-		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
-		complete(&cmd->transport_lun_stop_comp);
-		wait_for_completion(&cmd->transport_lun_fe_stop_comp);
-		spin_lock_irqsave(&cmd->t_state_lock, flags);
-
-		target_remove_from_state_list(cmd);
-		/*
-		 * At this point, the frontend who was the originator of this
-		 * struct se_cmd, now owns the structure and can be released through
-		 * normal means below.
-		 */
-		pr_debug("wait_for_tasks: Stopped"
-			" wait_for_completion(&cmd->t_tasktransport_lun_fe_"
-			"stop_comp); for ITT: 0x%08x\n",
-			cmd->se_tfo->get_task_tag(cmd));
-
-		cmd->transport_state &= ~CMD_T_LUN_STOP;
-	}
 
 	if (!(cmd->transport_state & CMD_T_ACTIVE)) {
 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
@@ -2910,6 +2692,7 @@ int transport_check_aborted_status(struct se_cmd *cmd, int send_status)
 		 cmd->t_task_cdb[0], cmd->se_tfo->get_task_tag(cmd));
 
 	cmd->se_cmd_flags |= SCF_SENT_DELAYED_TAS;
+	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
 	trace_target_cmd_complete(cmd);
 	cmd->se_tfo->queue_status(cmd);
 
@@ -2938,6 +2721,7 @@ void transport_send_task_abort(struct se_cmd *cmd)
 		if (cmd->se_tfo->write_pending_status(cmd) != 0) {
 			cmd->transport_state |= CMD_T_ABORTED;
 			smp_mb__after_atomic_inc();
+			return;
 		}
 	}
 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;