Commit b11e483a authored by Chaitanya Kulkarni's avatar Chaitanya Kulkarni Committed by Jens Axboe
Browse files

loop: clear nowait flag in workqueue context 



The loop driver advertises REQ_NOWAIT support through BLK_FEAT_NOWAIT
(enabled by default for all blk-mq devices), and honors the nowait
behavior throughout loop_queue_rq().

However, actual I/O to the backing file is performed in a workqueue,
where blocking is allowed.

To avoid imposing unnecessary non-blocking constraints in this blocking
context, clear the REQ_NOWAIT flag before processing the request in the
workqueue context.

Signed-off-by: default avatarChaitanya Kulkarni <ckulkarnilinux@gmail.com>
Reviewed-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a9637ab9

drivers/block/loop.c

+4 −0
Original line number Diff line number Diff line
@@ -2060,6 +2060,10 @@ static void loop_handle_cmd(struct loop_cmd *cmd) 
		goto failed;

	}



	/* We can block in this context, so ignore REQ_NOWAIT. */

	if (rq->cmd_flags & REQ_NOWAIT)

		rq->cmd_flags &= ~REQ_NOWAIT;



	if (cmd_blkcg_css)

		kthread_associate_blkcg(cmd_blkcg_css);

	if (cmd_memcg_css)