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>

8 files changed, 19 insertions, 6 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 2987fe47b5ee..6a9cc0d22a61 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -482,6 +482,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
         kobject_init(&q->kobj, &blk_queue_ktype);
 
         mutex_init(&q->sysfs_lock);
+        spin_lock_init(&q->__queue_lock);
 
         return q;
 }
@@ -544,10 +545,8 @@ blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
          * if caller didn't supply a lock, they get per-queue locking with
          * our embedded lock
          */
-        if (!lock) {
-                spin_lock_init(&q->__queue_lock);
+        if (!lock)
                 lock = &q->__queue_lock;
-        }
 
         q->request_fn           = rfn;
         q->prep_rq_fn           = NULL;
diff --git a/block/blk-settings.c b/block/blk-settings.c
index bb93d4c32775..8dd86418f35d 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -286,8 +286,14 @@ void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
         t->max_hw_segments = min(t->max_hw_segments, b->max_hw_segments);
         t->max_segment_size = min(t->max_segment_size, b->max_segment_size);
         t->hardsect_size = max(t->hardsect_size, b->hardsect_size);
-        if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags))
+        if (!t->queue_lock)
+                WARN_ON_ONCE(1);
+        else if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) {
+                unsigned long flags;
+                spin_lock_irqsave(t->queue_lock, flags);
                 queue_flag_clear(QUEUE_FLAG_CLUSTER, t);
+                spin_unlock_irqrestore(t->queue_lock, flags);
+        }
 }
 EXPORT_SYMBOL(blk_queue_stack_limits);
 
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 0b8511776b3e..10748240cb2f 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -250,6 +250,7 @@ static int linear_run (mddev_t *mddev)
 {
         linear_conf_t *conf;
 
+        mddev->queue->queue_lock = &mddev->queue->__queue_lock;
         conf = linear_conf(mddev, mddev->raid_disks);
 
         if (!conf)
diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index 42ee1a2dc144..4f4d1f383842 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -417,6 +417,7 @@ static int multipath_run (mddev_t *mddev)
          * bookkeeping area. [whatever we allocate in multipath_run(),
          * should be freed in multipath_stop()]
          */
+        mddev->queue->queue_lock = &mddev->queue->__queue_lock;
 
         conf = kzalloc(sizeof(multipath_conf_t), GFP_KERNEL);
         mddev->private = conf;
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 818b48284096..914c04ddec7c 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -280,6 +280,7 @@ static int raid0_run (mddev_t *mddev)
                (mddev->chunk_size>>1)-1);
         blk_queue_max_sectors(mddev->queue, mddev->chunk_size >> 9);
         blk_queue_segment_boundary(mddev->queue, (mddev->chunk_size>>1) - 1);
+        mddev->queue->queue_lock = &mddev->queue->__queue_lock;
 
         conf = kmalloc(sizeof (raid0_conf_t), GFP_KERNEL);
         if (!conf)
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 6778b7cb39bd..ac409b7d83f5 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1935,6 +1935,9 @@ static int run(mddev_t *mddev)
         if (!conf->r1bio_pool)
                 goto out_no_mem;
 
+        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
@@ -1958,7 +1961,6 @@ static int run(mddev_t *mddev)
         }
         conf->raid_disks = mddev->raid_disks;
         conf->mddev = mddev;
-        spin_lock_init(&conf->device_lock);
         INIT_LIST_HEAD(&conf->retry_list);
 
         spin_lock_init(&conf->resync_lock);
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);
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index ee0ea9183080..93fde48c0f42 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4257,6 +4257,7 @@ static int run(mddev_t *mddev)
                         goto abort;
         }
         spin_lock_init(&conf->device_lock);
+        mddev->queue->queue_lock = &conf->device_lock;
         init_waitqueue_head(&conf->wait_for_stripe);
         init_waitqueue_head(&conf->wait_for_overlap);
         INIT_LIST_HEAD(&conf->handle_list);