Commit 65c77fd9 authored by Jun'ichi Nomura's avatar Jun'ichi Nomura Committed by Jens Axboe
Browse files

blkcg: stop iteration early if root_rl is the only request list



__blk_queue_next_rl() finds next request list based on blkg_list
while skipping root_blkg in the list.
OTOH, root_rl is special as it may exist even without root_blkg.

Though the later part of the function handles such a case correctly,
exiting early is good for readability of the code.
Signed-off-by: default avatarJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: default avatarVivek Goyal <vgoyal@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 65635cbc
......@@ -333,6 +333,9 @@ struct request_list *__blk_queue_next_rl(struct request_list *rl,
*/
if (rl == &q->root_rl) {
ent = &q->blkg_list;
/* There are no more block groups, hence no request lists */
if (list_empty(ent))
return NULL;
} else {
blkg = container_of(rl, struct blkcg_gq, rl);
ent = &blkg->q_node;
......
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