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authorBart Van Assche <bart.vanassche@sandisk.com>2016-09-29 08:33:30 -0700
committerTejun Heo <tj@kernel.org>2016-09-30 10:31:20 +0200
commitbbb427e342495df1cda10051d0566388697499c0 (patch)
treef52002457cef52dd9e3cdcb490b6342a81767d9f /block/blk-cgroup.c
parente0223003e6e141533446d01a92784592a97a8552 (diff)
downloadlinux-bbb427e342495df1cda10051d0566388697499c0.tar.gz
blkcg: Unlock blkcg_pol_mutex only once when cpd == NULL
Unlocking a mutex twice is wrong. Hence modify blkcg_policy_register()
such that blkcg_pol_mutex is unlocked once if cpd == NULL. This patch
avoids that smatch reports the following error:

block/blk-cgroup.c:1378: blkcg_policy_register() error: double unlock 'mutex:&blkcg_pol_mutex'

Fixes: 06b285bd1125 ("blkcg: fix blkcg_policy_data allocation bug")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org> # v4.2+
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'block/blk-cgroup.c')
-rw-r--r--block/blk-cgroup.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index dd38e5ced4a3..b08ccbb9393a 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1340,10 +1340,8 @@ int blkcg_policy_register(struct blkcg_policy *pol)
 			struct blkcg_policy_data *cpd;
 
 			cpd = pol->cpd_alloc_fn(GFP_KERNEL);
-			if (!cpd) {
-				mutex_unlock(&blkcg_pol_mutex);
+			if (!cpd)
 				goto err_free_cpds;
-			}
 
 			blkcg->cpd[pol->plid] = cpd;
 			cpd->blkcg = blkcg;