Commit bbb427e3 authored Sep 29, 2016 by Bart Van Assche Committed by Tejun Heo Sep 30, 2016

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: 06b285bd ("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>

parent e0223003

block/blk-cgroup.c

+1 −3

Original line number	Diff line number	Diff line
		@@ -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;

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