blkcg: fix blkg_alloc() failure path

When policy data allocation fails in the middle, blkg_alloc() invokes
blkg_free() to destroy the half constructed blkg.  This ends up
calling pd_exit_fn() on policy datas which didn't go through
pd_init_fn().  Fix it by making blkg_alloc() call pd_init_fn()
immediately after each policy data allocation.

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

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 02cf633..4ab7420 100644 (file)
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -125,12 +125,8 @@ static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct request_queue *q)
 
                blkg->pd[i] = pd;
                pd->blkg = blkg;
-       }
-
-       /* invoke per-policy init */
-       for (i = 0; i < BLKCG_MAX_POLS; i++) {
-               struct blkcg_policy *pol = blkcg_policy[i];
 
+               /* invoke per-policy init */
                if (blkcg_policy_enabled(blkg->q, pol))
                        pol->pd_init_fn(blkg);
        }