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Commit 99ba2ae4 authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
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dm cache policy mq: protect residency method with existing mutex 



It is safe to use a mutex in mq_residency() at this point since it is
only called from ioctl context.  But future-proof mq_residency() by
using might_sleep() to catch new contexts that cannot sleep.

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 9c1d4de5

drivers/md/dm-cache-policy-mq.c

+6 −2
Original line number Diff line number Diff line
@@ -1001,10 +1001,14 @@ static void mq_force_mapping(struct dm_cache_policy *p, 


static dm_cblock_t mq_residency(struct dm_cache_policy *p)

{

	dm_cblock_t r;

	struct mq_policy *mq = to_mq_policy(p);



	/* FIXME: lock mutex, not sure we can block here */

	return to_cblock(mq->nr_cblocks_allocated);

	mutex_lock(&mq->lock);

	r = to_cblock(mq->nr_cblocks_allocated);

	mutex_unlock(&mq->lock);



	return r;

}



static void mq_tick(struct dm_cache_policy *p)