md: avoid spinlock problem in blk_throtl_exit

blk_throtl_exit assumes that ->queue_lock still exists,
so make sure that it does.
To do this, we stop redirecting ->queue_lock to conf->device_lock
and leave it pointing where it is initialised - __queue_lock.

As the blk_plug functions check the ->queue_lock is held, we now
take that spin_lock explicitly around the plug functions.  We don't
need the locking, just the warning removal.

This is needed for any kernel with the blk_throtl code, which is
which is 2.6.37 and later.

Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 8a2f767..0ed7f6b 100644 (file)
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -216,7 +216,6 @@ static int linear_run (mddev_t *mddev)
 
        if (md_check_no_bitmap(mddev))
                return -EINVAL;
-       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 6d7ddf3..3a62d44 100644 (file)
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -435,7 +435,6 @@ 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 75671df..c0ac457 100644 (file)
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -361,7 +361,6 @@ static int raid0_run(mddev_t *mddev)
        if (md_check_no_bitmap(mddev))
                return -EINVAL;
        blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
-       mddev->queue->queue_lock = &mddev->queue->__queue_lock;
 
        /* if private is not null, we are here after takeover */
        if (mddev->private == NULL) {

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index a23ffa3..06cd712 100644 (file)
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -593,7 +593,10 @@ static int flush_pending_writes(conf_t *conf)
        if (conf->pending_bio_list.head) {
                struct bio *bio;
                bio = bio_list_get(&conf->pending_bio_list);
+               /* Only take the spinlock to quiet a warning */
+               spin_lock(conf->mddev->queue->queue_lock);
                blk_remove_plug(conf->mddev->queue);
+               spin_unlock(conf->mddev->queue->queue_lock);
                spin_unlock_irq(&conf->device_lock);
                /* flush any pending bitmap writes to
                 * disk before proceeding w/ I/O */
@@ -959,7 +962,7 @@ static int make_request(mddev_t *mddev, struct bio * bio)
                atomic_inc(&r1_bio->remaining);
                spin_lock_irqsave(&conf->device_lock, flags);
                bio_list_add(&conf->pending_bio_list, mbio);
-               blk_plug_device(mddev->queue);
+               blk_plug_device_unlocked(mddev->queue);
                spin_unlock_irqrestore(&conf->device_lock, flags);
        }
        r1_bio_write_done(r1_bio, bio->bi_vcnt, behind_pages, behind_pages != NULL);
@@ -2021,7 +2024,6 @@ static int run(mddev_t *mddev)
        if (IS_ERR(conf))
                return PTR_ERR(conf);
 
-       mddev->queue->queue_lock = &conf->device_lock;
        list_for_each_entry(rdev, &mddev->disks, same_set) {
                disk_stack_limits(mddev->gendisk, rdev->bdev,
                                  rdev->data_offset << 9);

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 3b607b2..747d061 100644 (file)
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -662,7 +662,10 @@ static int flush_pending_writes(conf_t *conf)
        if (conf->pending_bio_list.head) {
                struct bio *bio;
                bio = bio_list_get(&conf->pending_bio_list);
+               /* Spinlock only taken to quiet a warning */
+               spin_lock(conf->mddev->queue->queue_lock);
                blk_remove_plug(conf->mddev->queue);
+               spin_unlock(conf->mddev->queue->queue_lock);
                spin_unlock_irq(&conf->device_lock);
                /* flush any pending bitmap writes to disk
                 * before proceeding w/ I/O */
@@ -971,7 +974,7 @@ static int make_request(mddev_t *mddev, struct bio * bio)
                atomic_inc(&r10_bio->remaining);
                spin_lock_irqsave(&conf->device_lock, flags);
                bio_list_add(&conf->pending_bio_list, mbio);
-               blk_plug_device(mddev->queue);
+               blk_plug_device_unlocked(mddev->queue);
                spin_unlock_irqrestore(&conf->device_lock, flags);
        }
 
@@ -2304,8 +2307,6 @@ static int run(mddev_t *mddev)
        if (!conf)
                goto out;
 
-       mddev->queue->queue_lock = &conf->device_lock;
-
        mddev->thread = conf->thread;
        conf->thread = NULL;
 

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 7028128..78536fd 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5204,7 +5204,6 @@ static int run(mddev_t *mddev)
 
                mddev->queue->backing_dev_info.congested_data = mddev;
                mddev->queue->backing_dev_info.congested_fn = raid5_congested;
-               mddev->queue->queue_lock = &conf->device_lock;
                mddev->queue->unplug_fn = raid5_unplug_queue;
 
                chunk_size = mddev->chunk_sectors << 9;