ublk: comment on ubq->canceling handling in ublk_queue_rq()

In ublk_queue_rq(), ubq->canceling has to be handled after ->fail_io and
->force_abort are dealt with, otherwise the request may not be failed
when deleting disk.

Add comment on this usage.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250327095123.179113-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index fbcb7c2ff8511d352c9f4c54ee559b76dfc375d4..5b0c885dc38f0f21d977ac114d8aaa36f353ce6e 100644 (file)
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -1310,6 +1310,11 @@ static blk_status_t ublk_queue_rq(struct blk_mq_hw_ctx *hctx,
        if (ublk_nosrv_should_queue_io(ubq) && unlikely(ubq->force_abort))
                return BLK_STS_IOERR;
 
+       /*
+        * ->canceling has to be handled after ->force_abort and ->fail_io
+        * is dealt with, otherwise this request may not be failed in case
+        * of recovery, and cause hang when deleting disk
+        */
        if (unlikely(ubq->canceling)) {
                __ublk_abort_rq(ubq, rq);
                return BLK_STS_OK;