blk-mq: add documentation for new queue attribute async_dpeth

Explain the attribute and the default value in different case.

Signed-off-by: Yu Kuai <yukuai@fnnas.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Yu Kuai 2026-02-03 16:19:49 +08:00 • committed by Jens Axboe
commit 2c04718edc