Patch "scsi: Avoid that SCSI queues get stuck" has been added to the 4.10-stable tree

This is a note to let you know that I've just added the patch titled

scsi: Avoid that SCSI queues get stuck

to the 4.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
scsi-avoid-that-scsi-queues-get-stuck.patch
and it can be found in the queue-4.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Bart Van Assche <[email protected]>
Date: Fri, 7 Apr 2017 11:16:53 -0700
Subject: scsi: Avoid that SCSI queues get stuck

From: Bart Van Assche <[email protected]>

commit 36e3cf273977da34a760d513e1bef8431a9abaa0 upstream.

If a .queue_rq() function returns BLK_MQ_RQ_QUEUE_BUSY then the block driver that implements that function is responsible for rerunning the hardware queue once requests can be queued again successfully.

commit 52d7f1b5c2f3 ("blk-mq: Avoid that requeueing starts stopped queues") removed the blk_mq_stop_hw_queue() call from scsi_queue_rq() for the BLK_MQ_RQ_QUEUE_BUSY case. Hence change all calls to functions that are intended to rerun a busy queue such that these examine all hardware queues instead of only stopped queues.

Since no other functions than scsi_internal_device_block() and scsi_internal_device_unblock() should ever stop or restart a SCSI queue, change the blk_mq_delay_queue() call into a blk_mq_delay_run_hw_queue() call.

---
 drivers/scsi/scsi_lib.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

@@ -468,7 +468,7 @@ static void scsi_run_queue(struct reques
 		scsi_starved_list_run(sdev->host);
 
 	if (q->mq_ops)
-		blk_mq_start_stopped_hw_queues(q, false);
+		blk_mq_run_hw_queues(q, false);
 	else
 		blk_run_queue(q);
 }

@@ -639,7 +639,7 @@ static bool scsi_end_request(struct requ
 		    !list_empty(&sdev->host->starved_list))
 			kblockd_schedule_work(&sdev->requeue_work);
 		else
-			blk_mq_start_stopped_hw_queues(q, true);
+			blk_mq_run_hw_queues(q, true);
 	} else {
 		unsigned long flags;
 

@@ -1953,7 +1953,7 @@ out:
 	case BLK_MQ_RQ_QUEUE_BUSY:
 		if (atomic_read(&sdev->device_busy) == 0 &&
 		    !scsi_device_blocked(sdev))
-			blk_mq_delay_queue(hctx, SCSI_QUEUE_DELAY);
+			blk_mq_delay_run_hw_queue(hctx, SCSI_QUEUE_DELAY);
 		break;
 	case BLK_MQ_RQ_QUEUE_ERROR:
 		/*

Patches currently in stable-queue which might be from [email protected] are

queue-4.10/scsi-avoid-that-scsi-queues-get-stuck.patch