Patch "scsi: avoid a permanent stop of the scsi device's request queue" has been added to the 4.9-stable tree

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

scsi: avoid a permanent stop of the scsi device's request queue

to the 4.9-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-a-permanent-stop-of-the-scsi-device-s-request-queue.patch
and it can be found in the queue-4.9 subdirectory.

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

From: Wei Fang <[email protected]>
Date: Tue, 13 Dec 2016 09:25:21 +0800
Subject: scsi: avoid a permanent stop of the scsi device's request queue

From: Wei Fang <[email protected]>

commit d2a145252c52792bc59e4767b486b26c430af4bb upstream.

A race between scanning and fc_remote_port_delete() may result in a permanent stop if the device gets blocked before scsi_sysfs_add_sdev() and unblocked after. The reason is that blocking a device sets both the SDEV_BLOCKED state and the QUEUE_FLAG_STOPPED. However, scsi_sysfs_add_sdev() unconditionally sets SDEV_RUNNING which causes the device to be ignored by scsi_target_unblock() and thus never have its QUEUE_FLAG_STOPPED cleared leading to a device which is apparently running but has a stopped queue.

We actually have two places where SDEV_RUNNING is set: once in scsi_add_lun() which respects the blocked flag and once in scsi_sysfs_add_sdev() which doesn't. Since the second set is entirely spurious, simply remove it to fix the problem.

---
 drivers/scsi/scsi_sysfs.c |    4 ----
 1 file changed, 4 deletions(-)

@@ -1204,10 +1204,6 @@ int scsi_sysfs_add_sdev(struct scsi_devi
 	struct request_queue *rq = sdev->request_queue;
 	struct scsi_target *starget = sdev->sdev_target;
 
-	error = scsi_device_set_state(sdev, SDEV_RUNNING);
-	if (error)
-		return error;
-
 	error = scsi_target_add(starget);
 	if (error)
 		return error;

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

queue-4.9/scsi-avoid-a-permanent-stop-of-the-scsi-device-s-request-queue.patch queue-4.9/block-protect-iterate_bdevs-against-concurrent-close.patch