Patch "dm mpath: check if path's request_queue is dying in activate_path()" has been added to the 4.8-stable tree

[<gregkh@linuxfoundation.org>]

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

    dm mpath: check if path's request_queue is dying in activate_path()

to the 4.8-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:
     dm-mpath-check-if-path-s-request_queue-is-dying-in-activate_path.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From f10e06b744074824fb8ec7066bc03ecc90918f5b Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer@redhat.com>
Date: Thu, 1 Sep 2016 12:06:37 -0400
Subject: dm mpath: check if path's request_queue is dying in activate_path()

From: Mike Snitzer <snitzer@redhat.com>

commit f10e06b744074824fb8ec7066bc03ecc90918f5b upstream.

If pg_init_retries is set and a request is queued against a multipath
device with all underlying block device request_queues in the "dying"
state then an infinite loop is triggered because activate_path() never
succeeds and hence never calls pg_init_done().

This change avoids that device removal triggers an infinite loop by
failing the activate_path() which causes the "dying" path to be failed.

Reported-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/md/dm-mpath.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1521,10 +1521,10 @@ static void activate_path(struct work_st
 {
 	struct pgpath *pgpath =
 		container_of(work, struct pgpath, activate_path.work);
+	struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev);
 
-	if (pgpath->is_active)
-		scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev),
-				 pg_init_done, pgpath);
+	if (pgpath->is_active && !blk_queue_dying(q))
+		scsi_dh_activate(q, pg_init_done, pgpath);
 	else
 		pg_init_done(pgpath, SCSI_DH_DEV_OFFLINED);
 }


Patches currently in stable-queue which might be from snitzer@redhat.com are

queue-4.8/dm-crypt-fix-crash-on-exit.patch
queue-4.8/dm-rq-take-request_queue-lock-while-clearing-queue_flag_stopped.patch
queue-4.8/dm-mark-request_queue-dead-before-destroying-the-dm-device.patch
queue-4.8/dm-mpath-check-if-path-s-request_queue-is-dying-in-activate_path.patch
queue-4.8/dm-return-correct-error-code-in-dm_resume-s-retry-loop.patch