diff options
| author | Dennis Zhou <dennis@kernel.org> | 2018-10-20 14:56:11 -0400 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-10-20 15:39:54 -0600 |
| commit | b2c3fa546705944e748666b474ffdaebaec0569f (patch) | |
| tree | e55b5f8cb1fd71a8a72013b3bff8147de415b979 | |
| parent | bbc152825afc869ed6e0b58fdc5e3e477a6c15d5 (diff) | |
| download | linux-b2c3fa546705944e748666b474ffdaebaec0569f.tar.bz2 | |
blkcg: fix edge case for blk_get_rl() under memory pressure
It is possible for blkg creation to fail when in blk_get_rl(). In this
situation, the fallback logic returns the nearest created blkg. There is
however special handling for the request_list for the root blkcg. This
fixes the missing edge case from the earlier series changing
blk_get_rl().
Fixes: e2b0989954ae ("blkcg: cleanup and make blk_get_rl use blkg_lookup_create")
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | include/linux/blk-cgroup.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index b7fd08013de2..1e76ceebeb5d 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -597,7 +597,7 @@ static inline struct request_list *blk_get_rl(struct request_queue *q, if (unlikely(!blkg)) blkg = __blkg_lookup_create(blkcg, q); - if (!blkg_tryget(blkg)) + if (blkg->blkcg == &blkcg_root || !blkg_tryget(blkg)) goto rl_use_root; rcu_read_unlock(); |