1 files changed, 50 insertions, 54 deletions

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 6dfb9785d345..b58327758c58 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -109,7 +109,7 @@ static void scsi_unprep_request(struct request *req)
  * for a requeue after completion, which should only occur in this
  * file.
  */
-static int __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
+static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
 {
 	struct Scsi_Host *host = cmd->device->host;
 	struct scsi_device *device = cmd->device;
@@ -155,15 +155,14 @@ static int __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
 
 	/*
 	 * Requeue this command.  It will go before all other commands
-	 * that are already in the queue.
+	 * that are already in the queue. Schedule requeue work under
+	 * lock such that the kblockd_schedule_work() call happens
+	 * before blk_cleanup_queue() finishes.
 	 */
 	spin_lock_irqsave(q->queue_lock, flags);
 	blk_requeue_request(q, cmd->request);
-	spin_unlock_irqrestore(q->queue_lock, flags);
-
 	kblockd_schedule_work(q, &device->requeue_work);
-
-	return 0;
+	spin_unlock_irqrestore(q->queue_lock, flags);
 }
 
 /*
@@ -185,9 +184,9 @@ static int __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
  * Notes:       This could be called either from an interrupt context or a
  *              normal process context.
  */
-int scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
+void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
 {
-	return __scsi_queue_insert(cmd, reason, 1);
+	__scsi_queue_insert(cmd, reason, 1);
 }
 /**
  * scsi_execute - insert request and wait for the result
@@ -406,10 +405,6 @@ static void scsi_run_queue(struct request_queue *q)
 	LIST_HEAD(starved_list);
 	unsigned long flags;
 
-	/* if the device is dead, sdev will be NULL, so no queue to run */
-	if (!sdev)
-		return;
-
 	shost = sdev->host;
 	if (scsi_target(sdev)->single_lun)
 		scsi_single_lun_run(sdev);
@@ -483,15 +478,26 @@ void scsi_requeue_run_queue(struct work_struct *work)
  */
 static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
 {
+	struct scsi_device *sdev = cmd->device;
 	struct request *req = cmd->request;
 	unsigned long flags;
 
+	/*
+	 * We need to hold a reference on the device to avoid the queue being
+	 * killed after the unlock and before scsi_run_queue is invoked which
+	 * may happen because scsi_unprep_request() puts the command which
+	 * releases its reference on the device.
+	 */
+	get_device(&sdev->sdev_gendev);
+
 	spin_lock_irqsave(q->queue_lock, flags);
 	scsi_unprep_request(req);
 	blk_requeue_request(q, req);
 	spin_unlock_irqrestore(q->queue_lock, flags);
 
 	scsi_run_queue(q);
+
+	put_device(&sdev->sdev_gendev);
 }
 
 void scsi_next_command(struct scsi_cmnd *cmd)
@@ -1173,6 +1179,7 @@ int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
 	if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
 		switch (sdev->sdev_state) {
 		case SDEV_OFFLINE:
+		case SDEV_TRANSPORT_OFFLINE:
 			/*
 			 * If the device is offline we refuse to process any
 			 * commands.  The device must be brought online
@@ -1370,16 +1377,16 @@ static inline int scsi_host_queue_ready(struct request_queue *q,
  * may be changed after request stacking drivers call the function,
  * regardless of taking lock or not.
  *
- * When scsi can't dispatch I/Os anymore and needs to kill I/Os
- * (e.g. !sdev), scsi needs to return 'not busy'.
- * Otherwise, request stacking drivers may hold requests forever.
+ * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
+ * needs to return 'not busy'. Otherwise, request stacking drivers
+ * may hold requests forever.
  */
 static int scsi_lld_busy(struct request_queue *q)
 {
 	struct scsi_device *sdev = q->queuedata;
 	struct Scsi_Host *shost;
 
-	if (!sdev)
+	if (blk_queue_dead(q))
 		return 0;
 
 	shost = sdev->host;
@@ -1490,12 +1497,6 @@ static void scsi_request_fn(struct request_queue *q)
 	struct scsi_cmnd *cmd;
 	struct request *req;
 
-	if (!sdev) {
-		while ((req = blk_peek_request(q)) != NULL)
-			scsi_kill_request(req, q);
-		return;
-	}
-
 	if(!get_device(&sdev->sdev_gendev))
 		/* We must be tearing the block queue down already */
 		return;
@@ -1697,20 +1698,6 @@ struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
 	return q;
 }
 
-void scsi_free_queue(struct request_queue *q)
-{
-	unsigned long flags;
-
-	WARN_ON(q->queuedata);
-
-	/* cause scsi_request_fn() to kill all non-finished requests */
-	spin_lock_irqsave(q->queue_lock, flags);
-	q->request_fn(q);
-	spin_unlock_irqrestore(q->queue_lock, flags);
-
-	blk_cleanup_queue(q);
-}
-
 /*
  * Function:    scsi_block_requests()
  *
@@ -2081,6 +2068,7 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
 		switch (oldstate) {
 		case SDEV_CREATED:
 		case SDEV_OFFLINE:
+		case SDEV_TRANSPORT_OFFLINE:
 		case SDEV_QUIESCE:
 		case SDEV_BLOCK:
 			break;
@@ -2093,6 +2081,7 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
 		switch (oldstate) {
 		case SDEV_RUNNING:
 		case SDEV_OFFLINE:
+		case SDEV_TRANSPORT_OFFLINE:
 			break;
 		default:
 			goto illegal;
@@ -2100,6 +2089,7 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
 		break;
 
 	case SDEV_OFFLINE:
+	case SDEV_TRANSPORT_OFFLINE:
 		switch (oldstate) {
 		case SDEV_CREATED:
 		case SDEV_RUNNING:
@@ -2136,6 +2126,7 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
 		case SDEV_RUNNING:
 		case SDEV_QUIESCE:
 		case SDEV_OFFLINE:
+		case SDEV_TRANSPORT_OFFLINE:
 		case SDEV_BLOCK:
 			break;
 		default:
@@ -2148,6 +2139,7 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
 		case SDEV_CREATED:
 		case SDEV_RUNNING:
 		case SDEV_OFFLINE:
+		case SDEV_TRANSPORT_OFFLINE:
 		case SDEV_CANCEL:
 			break;
 		default:
@@ -2405,7 +2397,6 @@ EXPORT_SYMBOL(scsi_target_resume);
  *	(which must be a legal transition).  When the device is in this
  *	state, all commands are deferred until the scsi lld reenables
  *	the device with scsi_device_unblock or device_block_tmo fires.
- *	This routine assumes the host_lock is held on entry.
  */
 int
 scsi_internal_device_block(struct scsi_device *sdev)
@@ -2438,6 +2429,7 @@ EXPORT_SYMBOL_GPL(scsi_internal_device_block);
 /**
  * scsi_internal_device_unblock - resume a device after a block request
  * @sdev:	device to resume
+ * @new_state:	state to set devices to after unblocking
  *
  * Called by scsi lld's or the midlayer to restart the device queue
  * for the previously suspended scsi device.  Called from interrupt or
@@ -2447,25 +2439,29 @@ EXPORT_SYMBOL_GPL(scsi_internal_device_block);
  *
  * Notes:       
  *	This routine transitions the device to the SDEV_RUNNING state
- *	(which must be a legal transition) allowing the midlayer to
- *	goose the queue for this device.  This routine assumes the 
- *	host_lock is held upon entry.
+ *	or to one of the offline states (which must be a legal transition)
+ *	allowing the midlayer to goose the queue for this device.
  */
 int
-scsi_internal_device_unblock(struct scsi_device *sdev)
+scsi_internal_device_unblock(struct scsi_device *sdev,
+			     enum scsi_device_state new_state)
 {
 	struct request_queue *q = sdev->request_queue; 
 	unsigned long flags;
-	
-	/* 
-	 * Try to transition the scsi device to SDEV_RUNNING
-	 * and goose the device queue if successful.  
+
+	/*
+	 * Try to transition the scsi device to SDEV_RUNNING or one of the
+	 * offlined states and goose the device queue if successful.
 	 */
 	if (sdev->sdev_state == SDEV_BLOCK)
-		sdev->sdev_state = SDEV_RUNNING;
-	else if (sdev->sdev_state == SDEV_CREATED_BLOCK)
-		sdev->sdev_state = SDEV_CREATED;
-	else if (sdev->sdev_state != SDEV_CANCEL &&
+		sdev->sdev_state = new_state;
+	else if (sdev->sdev_state == SDEV_CREATED_BLOCK) {
+		if (new_state == SDEV_TRANSPORT_OFFLINE ||
+		    new_state == SDEV_OFFLINE)
+			sdev->sdev_state = new_state;
+		else
+			sdev->sdev_state = SDEV_CREATED;
+	} else if (sdev->sdev_state != SDEV_CANCEL &&
 		 sdev->sdev_state != SDEV_OFFLINE)
 		return -EINVAL;
 
@@ -2506,26 +2502,26 @@ EXPORT_SYMBOL_GPL(scsi_target_block);
 static void
 device_unblock(struct scsi_device *sdev, void *data)
 {
-	scsi_internal_device_unblock(sdev);
+	scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
 }
 
 static int
 target_unblock(struct device *dev, void *data)
 {
 	if (scsi_is_target_device(dev))
-		starget_for_each_device(to_scsi_target(dev), NULL,
+		starget_for_each_device(to_scsi_target(dev), data,
 					device_unblock);
 	return 0;
 }
 
 void
-scsi_target_unblock(struct device *dev)
+scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
 {
 	if (scsi_is_target_device(dev))
-		starget_for_each_device(to_scsi_target(dev), NULL,
+		starget_for_each_device(to_scsi_target(dev), &new_state,
 					device_unblock);
 	else
-		device_for_each_child(dev, NULL, target_unblock);
+		device_for_each_child(dev, &new_state, target_unblock);
 }
 EXPORT_SYMBOL_GPL(scsi_target_unblock);