Remove blkdev warning triggered by using md

As setting and clearing queue flags now requires that we hold a spinlock
on the queue, and as blk_queue_stack_limits is called without that lock,
get the lock inside blk_queue_stack_limits.

For blk_queue_stack_limits to be able to find the right lock, each md
personality needs to set q->queue_lock to point to the appropriate lock.
Those personalities which didn't previously use a spin_lock, us
q->__queue_lock.  So always initialise that lock when allocated.

With this in place, setting/clearing of the QUEUE_FLAG_PLUGGED bit will no
longer cause warnings as it will be clear that the proper lock is held.

Thanks to Dan Williams for review and fixing the silly bugs.

Signed-off-by: NeilBrown <neilb@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Alistair John Strachan <alistair@devzero.co.uk>
Cc: Nick Piggin <npiggin@suse.de>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Jacek Luczak <difrost.kernel@gmail.com>
Cc: Prakash Punnoor <prakash@punnoor.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index faf3d8912979..8536ede1e712 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2082,6 +2082,9 @@ static int run(mddev_t *mddev)
                 goto out_free_conf;
         }
 
+        spin_lock_init(&conf->device_lock);
+        mddev->queue->queue_lock = &conf->device_lock;
+
         rdev_for_each(rdev, tmp, mddev) {
                 disk_idx = rdev->raid_disk;
                 if (disk_idx >= mddev->raid_disks
@@ -2103,7 +2106,6 @@ static int run(mddev_t *mddev)
 
                 disk->head_position = 0;
         }
-        spin_lock_init(&conf->device_lock);
         INIT_LIST_HEAD(&conf->retry_list);
 
         spin_lock_init(&conf->resync_lock);