1 files changed, 79 insertions, 68 deletions

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 73d0d6133ac8..e8b7955d40f2 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -22,7 +22,7 @@
 #include <linux/module.h>
 #include <linux/ratelimit.h>
 #include <linux/vmalloc.h>
-#include <asm/unaligned.h>
+#include <linux/unaligned.h>
 #include <net/sock.h>
 #include <net/tcp.h>
 #include <scsi/scsi_proto.h>
@@ -126,12 +126,12 @@ int init_se_kmem_caches(void)
 	}
 
 	target_completion_wq = alloc_workqueue("target_completion",
-					       WQ_MEM_RECLAIM, 0);
+					       WQ_MEM_RECLAIM | WQ_PERCPU, 0);
 	if (!target_completion_wq)
 		goto out_free_lba_map_mem_cache;
 
 	target_submission_wq = alloc_workqueue("target_submission",
-					       WQ_MEM_RECLAIM, 0);
+					       WQ_MEM_RECLAIM | WQ_PERCPU, 0);
 	if (!target_submission_wq)
 		goto out_free_completion_wq;
 
@@ -1571,7 +1571,12 @@ target_cmd_parse_cdb(struct se_cmd *cmd)
 		return ret;
 
 	cmd->se_cmd_flags |= SCF_SUPPORTED_SAM_OPCODE;
-	atomic_long_inc(&cmd->se_lun->lun_stats.cmd_pdus);
+	/*
+	 * If this is the xcopy_lun then we won't have lun_stats since we
+	 * can't export them.
+	 */
+	if (cmd->se_lun->lun_stats)
+		this_cpu_inc(cmd->se_lun->lun_stats->cmd_pdus);
 	return 0;
 }
 EXPORT_SYMBOL(target_cmd_parse_cdb);
@@ -2213,6 +2218,7 @@ static int target_write_prot_action(struct se_cmd *cmd)
 static bool target_handle_task_attr(struct se_cmd *cmd)
 {
 	struct se_device *dev = cmd->se_dev;
+	unsigned long flags;
 
 	if (dev->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
 		return false;
@@ -2225,13 +2231,10 @@ static bool target_handle_task_attr(struct se_cmd *cmd)
 	 */
 	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;
@@ -2239,29 +2242,29 @@ static bool target_handle_task_attr(struct se_cmd *cmd)
 		/*
 		 * For SIMPLE and UNTAGGED Task Attribute commands
 		 */
-		atomic_inc_mb(&dev->non_ordered);
-
-		if (atomic_read(&dev->delayed_cmd_count) == 0)
+retry:
+		if (percpu_ref_tryget_live(&dev->non_ordered))
 			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_irqsave(&dev->delayed_cmd_lock, flags);
+	if (cmd->sam_task_attr == TCM_SIMPLE_TAG &&
+	    !percpu_ref_is_dying(&dev->non_ordered)) {
+		spin_unlock_irqrestore(&dev->delayed_cmd_lock, flags);
+		/* We raced with the last ordered completion so retry. */
+		goto retry;
+	} else if (!percpu_ref_is_dying(&dev->non_ordered)) {
+		percpu_ref_kill(&dev->non_ordered);
 	}
 
-	spin_lock_irq(&cmd->t_state_lock);
+	spin_lock(&cmd->t_state_lock);
 	cmd->transport_state &= ~CMD_T_SENT;
-	spin_unlock_irq(&cmd->t_state_lock);
+	spin_unlock(&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);
+	spin_unlock_irqrestore(&dev->delayed_cmd_lock, flags);
 
 	pr_debug("Added CDB: 0x%02x Task Attr: 0x%02x to delayed CMD listn",
 		cmd->t_task_cdb[0], cmd->sam_task_attr);
@@ -2313,41 +2316,52 @@ void target_do_delayed_work(struct work_struct *work)
 	while (!dev->ordered_sync_in_progress) {
 		struct se_cmd *cmd;
 
-		if (list_empty(&dev->delayed_cmd_list))
+		/*
+		 * We can be woken up early/late due to races or the
+		 * extra wake up we do when adding commands to the list.
+		 * We check for both cases here.
+		 */
+		if (list_empty(&dev->delayed_cmd_list) ||
+		    !percpu_ref_is_zero(&dev->non_ordered))
 			break;
 
 		cmd = list_entry(dev->delayed_cmd_list.next,
 				 struct se_cmd, se_delayed_node);
+		cmd->se_cmd_flags |= SCF_TASK_ORDERED_SYNC;
+		cmd->transport_state |= CMD_T_SENT;
 
-		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;
-		}
+		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);
 }
 
+static void transport_complete_ordered_sync(struct se_cmd *cmd)
+{
+	struct se_device *dev = cmd->se_dev;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->delayed_cmd_lock, flags);
+	dev->dev_cur_ordered_id++;
+
+	pr_debug("Incremented dev_cur_ordered_id: %u for type %d\n",
+		 dev->dev_cur_ordered_id, cmd->sam_task_attr);
+
+	dev->ordered_sync_in_progress = false;
+
+	if (list_empty(&dev->delayed_cmd_list))
+		percpu_ref_resurrect(&dev->non_ordered);
+	else
+		schedule_work(&dev->delayed_cmd_work);
+
+	spin_unlock_irqrestore(&dev->delayed_cmd_lock, flags);
+}
+
 /*
  * Called from I/O completion to determine which dormant/delayed
  * and ordered cmds need to have their tasks added to the execution queue.
@@ -2360,30 +2374,24 @@ static void transport_complete_task_attr(struct se_cmd *cmd)
 		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);
+		return;
 
-		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);
+	if (cmd->se_cmd_flags & SCF_TASK_ORDERED_SYNC) {
+		transport_complete_ordered_sync(cmd);
+		return;
+	}
+
+	switch (cmd->sam_task_attr) {
+	case TCM_SIMPLE_TAG:
+		percpu_ref_put(&dev->non_ordered);
+		break;
+	case TCM_ORDERED_TAG:
+		/* All ordered should have been executed as sync */
+		WARN_ON(1);
+		break;
+	}
 }
 
 static void transport_complete_qf(struct se_cmd *cmd)
@@ -2594,8 +2602,9 @@ queue_rsp:
 		    !(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);
+		if (cmd->se_lun->lun_stats)
+			this_cpu_add(cmd->se_lun->lun_stats->tx_data_octets,
+				     cmd->data_length);
 		/*
 		 * Perform READ_STRIP of PI using software emulation when
 		 * backend had PI enabled, if the transport will not be
@@ -2618,14 +2627,16 @@ queue_rsp:
 			goto queue_full;
 		break;
 	case DMA_TO_DEVICE:
-		atomic_long_add(cmd->data_length,
-				&cmd->se_lun->lun_stats.rx_data_octets);
+		if (cmd->se_lun->lun_stats)
+			this_cpu_add(cmd->se_lun->lun_stats->rx_data_octets,
+				     cmd->data_length);
 		/*
 		 * 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);
+			if (cmd->se_lun->lun_stats)
+				this_cpu_add(cmd->se_lun->lun_stats->tx_data_octets,
+					     cmd->data_length);
 			ret = cmd->se_tfo->queue_data_in(cmd);
 			if (ret)
 				goto queue_full;