[PATCH 02/11] blkcg: use blkg_free() in blkcg_init_queue() failure path

From: Tejun Heo
Date: Sat Jul 11 2015 - 14:03:32 EST


When blkcg_init_queue() fails midway after creating a new blkg, it
performs kfree() directly; however, this doesn't free the policy data
areas. Make it use blkg_free() instead. In turn, blkg_free() is
updated to handle root request_list special case.

While this fixes a possible memory leak, it's on an unlikely failure
path of an already cold path and the size leaked per occurrence is
miniscule too. I don't think it needs to be tagged for -stable.

Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
---
block/blk-cgroup.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index fbb0b65..64cc48f 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -70,7 +70,8 @@ static void blkg_free(struct blkcg_gq *blkg)
for (i = 0; i < BLKCG_MAX_POLS; i++)
kfree(blkg->pd[i]);

- blk_exit_rl(&blkg->rl);
+ if (blkg->blkcg != &blkcg_root)
+ blk_exit_rl(&blkg->rl);
kfree(blkg);
}

@@ -934,7 +935,7 @@ int blkcg_init_queue(struct request_queue *q)
radix_tree_preload_end();

if (IS_ERR(blkg)) {
- kfree(new_blkg);
+ blkg_free(new_blkg);
return PTR_ERR(blkg);
}

--
2.4.3

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