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| author |   Joe Thornber <ejt@redhat.com> | 2013-10-21 11:44:57 +0100 |
|---|---|---|
| committer |   Mike Snitzer <snitzer@redhat.com> | 2013-11-09 17:54:34 -0500 |
| commit | 99ba2ae4cd876bbcedb01d94c1a7952ce171418e (patch) | |
| tree | e150c06aff63538e6c64ff29a88f6afdb9d9fe20 /drivers/md/dm-cache-policy-mq.c | |
| parent | dm array: fix bug in growing array (diff) | |
| download | linux-dev-99ba2ae4cd876bbcedb01d94c1a7952ce171418e.tar.xz linux-dev-99ba2ae4cd876bbcedb01d94c1a7952ce171418e.zip | |
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: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-cache-policy-mq.c')
| -rw-r--r-- | drivers/md/dm-cache-policy-mq.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/md/dm-cache-policy-mq.c b/drivers/md/dm-cache-policy-mq.c index 4296155090b2..db490f74c7f8 100644 --- a/drivers/md/dm-cache-policy-mq.c +++ b/drivers/md/dm-cache-policy-mq.c @@ -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) |