From: Joe Thornber Date: Mon, 3 Mar 2014 15:46:42 +0000 (+0000) Subject: dm thin: fix deadlock in __requeue_bio_list X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=18adc57779866ba451237dccca2ebf019be2fa20;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git dm thin: fix deadlock in __requeue_bio_list The spin lock in requeue_io() was held for too long, allowing deadlock. Don't worry, due to other issues addressed in the following "dm thin: fix noflush suspend IO queueing" commit, this code was never called. Fix this by taking the spin lock for a much shorter period of time. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer --- diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index 38a063f7afa4..f39876dd307d 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -369,14 +369,18 @@ struct dm_thin_endio_hook { struct dm_thin_new_mapping *overwrite_mapping; }; -static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master) +static void requeue_bio_list(struct thin_c *tc, struct bio_list *master) { struct bio *bio; struct bio_list bios; + unsigned long flags; bio_list_init(&bios); + + spin_lock_irqsave(&tc->pool->lock, flags); bio_list_merge(&bios, master); bio_list_init(master); + spin_unlock_irqrestore(&tc->pool->lock, flags); while ((bio = bio_list_pop(&bios))) { struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); @@ -391,12 +395,9 @@ static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master) static void requeue_io(struct thin_c *tc) { struct pool *pool = tc->pool; - unsigned long flags; - spin_lock_irqsave(&pool->lock, flags); - __requeue_bio_list(tc, &pool->deferred_bios); - __requeue_bio_list(tc, &pool->retry_on_resume_list); - spin_unlock_irqrestore(&pool->lock, flags); + requeue_bio_list(tc, &pool->deferred_bios); + requeue_bio_list(tc, &pool->retry_on_resume_list); } static void error_retry_list(struct pool *pool)