From: Tejun Heo <tj@kernel.org>
Date: Tue, 14 May 2013 20:52:30 +0000 (-0700)
Subject: blkcg: fix error return path in blkg_create()
X-Git-Tag: MMI-PSA29.97-13-9~13965^2~53
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=2423c9c3f0ffffa8f87cbdafe9781273c5d1b6a2;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git

blkcg: fix error return path in blkg_create()

In blkg_create(), after lookup of parent fails, the control jumps to
error path with the error code encoded into @blkg.  The error path
doesn't use @blkg for the return value.  It returns ERR_PTR(ret).
Make lookup fail path set @ret instead of @blkg.

Note that the parent lookup is guaranteed to succeed at that point and
the condition check is purely for sanity and triggers WARN when fails.
As such, I don't think it's necessary to mark it for -stable.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
---

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index e8918ffaf96d..7fc35f683c4e 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -238,7 +238,7 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
 	if (blkcg_parent(blkcg)) {
 		blkg->parent = __blkg_lookup(blkcg_parent(blkcg), q, false);
 		if (WARN_ON_ONCE(!blkg->parent)) {
-			blkg = ERR_PTR(-EINVAL);
+			ret = -EINVAL;
 			goto err_put_css;
 		}
 		blkg_get(blkg->parent);