diff options
Diffstat (limited to 'block/blk-cgroup.c')
| -rw-r--r-- | block/blk-cgroup.c | 23 |
1 files changed, 16 insertions, 7 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index b421a9457e05..120f2e2835fb 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -258,9 +258,8 @@ err_free_blkg: * 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. * - * Returns pointer to the looked up or created blkg on success, ERR_PTR() - * value on error. If @q is dead, returns ERR_PTR(-EINVAL). If @q is not - * dead and bypassing, returns ERR_PTR(-EBUSY). + * Returns the blkg or the closest blkg if blkg_create() fails as it walks + * down from root. */ struct blkcg_gq *__blkg_lookup_create(struct blkcg *blkcg, struct request_queue *q) @@ -276,19 +275,29 @@ struct blkcg_gq *__blkg_lookup_create(struct blkcg *blkcg, /* * Create blkgs walking down from blkcg_root to @blkcg, so that all - * non-root blkgs have access to their parents. + * non-root blkgs have access to their parents. Returns the closest + * blkg to the intended blkg should blkg_create() fail. */ while (true) { struct blkcg *pos = blkcg; struct blkcg *parent = blkcg_parent(blkcg); - - while (parent && !__blkg_lookup(parent, q, false)) { + struct blkcg_gq *ret_blkg = q->root_blkg; + + while (parent) { + blkg = __blkg_lookup(parent, q, false); + if (blkg) { + /* remember closest blkg */ + ret_blkg = blkg; + break; + } pos = parent; parent = blkcg_parent(parent); } blkg = blkg_create(pos, q, NULL); - if (pos == blkcg || IS_ERR(blkg)) + if (IS_ERR(blkg)) + return ret_blkg; + if (pos == blkcg) return blkg; } } |