diff options
Diffstat (limited to 'block/blk-cgroup.c')
-rw-r--r-- | block/blk-cgroup.c | 49 |
1 files changed, 18 insertions, 31 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index bb0607bfd771..6aedb73ffbf4 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -316,30 +316,35 @@ err_free_blkg: } /** - * __blkg_lookup_create - lookup blkg, try to create one if not there + * blkg_lookup_create - lookup blkg, try to create one if not there * @blkcg: blkcg of interest * @q: request_queue of interest * * Lookup blkg for the @blkcg - @q pair. If it doesn't exist, try to * create one. blkg creation is performed recursively from blkcg_root such * that all non-root blkg's have access to the parent blkg. This function - * should be called under RCU read lock and @q->queue_lock. + * should be called under RCU read lock and takes @q->queue_lock. * * Returns the blkg or the closest blkg if blkg_create() fails as it walks * down from root. */ -static struct blkcg_gq *__blkg_lookup_create(struct blkcg *blkcg, - struct request_queue *q) +static struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg, + struct request_queue *q) { struct blkcg_gq *blkg; + unsigned long flags; WARN_ON_ONCE(!rcu_read_lock_held()); - lockdep_assert_held(&q->queue_lock); - blkg = __blkg_lookup(blkcg, q, true); + blkg = blkg_lookup(blkcg, q); if (blkg) return blkg; + spin_lock_irqsave(&q->queue_lock, flags); + blkg = __blkg_lookup(blkcg, q, true); + if (blkg) + goto found; + /* * Create blkgs walking down from blkcg_root to @blkcg, so that all * non-root blkgs have access to their parents. Returns the closest @@ -362,34 +367,16 @@ static struct blkcg_gq *__blkg_lookup_create(struct blkcg *blkcg, } blkg = blkg_create(pos, q, NULL); - if (IS_ERR(blkg)) - return ret_blkg; + if (IS_ERR(blkg)) { + blkg = ret_blkg; + break; + } if (pos == blkcg) - return blkg; - } -} - -/** - * blkg_lookup_create - find or create a blkg - * @blkcg: target block cgroup - * @q: target request_queue - * - * This looks up or creates the blkg representing the unique pair - * of the blkcg and the request_queue. - */ -static struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg, - struct request_queue *q) -{ - struct blkcg_gq *blkg = blkg_lookup(blkcg, q); - - if (unlikely(!blkg)) { - unsigned long flags; - - spin_lock_irqsave(&q->queue_lock, flags); - blkg = __blkg_lookup_create(blkcg, q); - spin_unlock_irqrestore(&q->queue_lock, flags); + break; } +found: + spin_unlock_irqrestore(&q->queue_lock, flags); return blkg; } |