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

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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.

Reported-by: Zengxi Chen <chenzengxi@huawei.com>
Signed-off-by: Wei Fang <fangwei1@huawei.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Wei Fang 2016-12-13 09:25:21 +08:00 committed by Greg Kroah-Hartman
parent 565ae61d89
commit dbb67e1d58
1 changed files with 0 additions and 4 deletions
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4
drivers/scsi/scsi_sysfs.c
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@ -1031,10 +1031,6 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
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;