blk-mq: fix potential race in queue restart and driver tag allocation
Once we mark the queue as needing a restart, re-check if we can get a driver tag. This fixes a theoretical issue where the needed IO completes _after_ blk_mq_get_driver_tag() fails, but before we manage to set the restart bit. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Tested-by: Hannes Reinecke <hare@suse.com>
This commit is contained in:
Родитель
0abad77412
Коммит
3c782d67c1
|
@ -928,8 +928,16 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list)
|
|||
if (!blk_mq_get_driver_tag(rq, &hctx, false)) {
|
||||
if (!queued && reorder_tags_to_front(list))
|
||||
continue;
|
||||
|
||||
/*
|
||||
* We failed getting a driver tag. Mark the queue(s)
|
||||
* as needing a restart. Retry getting a tag again,
|
||||
* in case the needed IO completed right before we
|
||||
* marked the queue as needing a restart.
|
||||
*/
|
||||
blk_mq_sched_mark_restart(hctx);
|
||||
break;
|
||||
if (!blk_mq_get_driver_tag(rq, &hctx, false))
|
||||
break;
|
||||
}
|
||||
list_del_init(&rq->queuelist);
|
||||
|
||||
|
|
Загрузка…
Ссылка в новой задаче