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| author |   Mikulas Patocka <mpatocka@redhat.com> | 2013-11-15 16:12:20 -0500 |
|---|---|---|
| committer |   Mike Snitzer <snitzer@redhat.com> | 2013-11-18 11:23:21 -0500 |
| commit | 718822c1c112dc99e0c72c8968ee1db9d9d910f0 (patch) | |
| tree | fa1d459ccf22f9944af10fde35a5dbd28fd7a45e /drivers | |
| parent | dm cache: resolve small nits and improve Documentation (diff) | |
| download | linux-dev-718822c1c112dc99e0c72c8968ee1db9d9d910f0.tar.xz linux-dev-718822c1c112dc99e0c72c8968ee1db9d9d910f0.zip | |
dm delay: fix a possible deadlock due to shared workqueue
The dm-delay target uses a shared workqueue for multiple instances. This
can cause deadlock if two or more dm-delay targets are stacked on the top
of each other.
This patch changes dm-delay to use a per-instance workqueue.
Cc: stable@vger.kernel.org # 2.6.22+
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/md/dm-delay.c | 23 |
1 files changed, 11 insertions, 12 deletions
diff --git a/drivers/md/dm-delay.c b/drivers/md/dm-delay.c index 496d5f3646a5..2f91d6d4a2cc 100644 --- a/drivers/md/dm-delay.c +++ b/drivers/md/dm-delay.c @@ -20,6 +20,7 @@ struct delay_c { struct timer_list delay_timer; struct mutex timer_lock; + struct workqueue_struct *kdelayd_wq; struct work_struct flush_expired_bios; struct list_head delayed_bios; atomic_t may_delay; @@ -45,14 +46,13 @@ struct dm_delay_info { static DEFINE_MUTEX(delayed_bios_lock); -static struct workqueue_struct *kdelayd_wq; static struct kmem_cache *delayed_cache; static void handle_delayed_timer(unsigned long data) { struct delay_c *dc = (struct delay_c *)data; - queue_work(kdelayd_wq, &dc->flush_expired_bios); + queue_work(dc->kdelayd_wq, &dc->flush_expired_bios); } static void queue_timeout(struct delay_c *dc, unsigned long expires) @@ -191,6 +191,12 @@ out: goto bad_dev_write; } + dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0); + if (!dc->kdelayd_wq) { + DMERR("Couldn't start kdelayd"); + goto bad_queue; + } + setup_timer(&dc->delay_timer, handle_delayed_timer, (unsigned long)dc); INIT_WORK(&dc->flush_expired_bios, flush_expired_bios); @@ -203,6 +209,8 @@ out: ti->private = dc; return 0; +bad_queue: + mempool_destroy(dc->delayed_pool); bad_dev_write: if (dc->dev_write) dm_put_device(ti, dc->dev_write); @@ -217,7 +225,7 @@ static void delay_dtr(struct dm_target *ti) { struct delay_c *dc = ti->private; - flush_workqueue(kdelayd_wq); + destroy_workqueue(dc->kdelayd_wq); dm_put_device(ti, dc->dev_read); @@ -350,12 +358,6 @@ static int __init dm_delay_init(void) { int r = -ENOMEM; - kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0); - if (!kdelayd_wq) { - DMERR("Couldn't start kdelayd"); - goto bad_queue; - } - delayed_cache = KMEM_CACHE(dm_delay_info, 0); if (!delayed_cache) { DMERR("Couldn't create delayed bio cache."); @@ -373,8 +375,6 @@ static int __init dm_delay_init(void) bad_register: kmem_cache_destroy(delayed_cache); bad_memcache: - destroy_workqueue(kdelayd_wq); -bad_queue: return r; } @@ -382,7 +382,6 @@ static void __exit dm_delay_exit(void) { dm_unregister_target(&delay_target); kmem_cache_destroy(delayed_cache); - destroy_workqueue(kdelayd_wq); } /* Module hooks */ |