Commit f22ecf9c authored by Fengnan Chang's avatar Fengnan Chang Committed by Jens Axboe
Browse files

blk-mq: delete task running check in blk_hctx_poll() 



blk_hctx_poll() always checks if the task is running or not, and returns
1 if the task is running. This is a leftover from when polled IO was
purely for synchronous IO, and doesn't make sense anymore when polled IO
is purely asynchronous. Similarly, marking the task as TASK_RUNNING is
also superflous, as the very much has to be running to enter the
function in the first place.

It looks like there has been this judgment for historical reasons, and
in very early versions of this function the user would set the process
state to TASK_UNINTERRUPTIBLE.

Signed-off-by: default avatarDiangang Li <lidiangang@bytedance.com>
Signed-off-by: default avatarFengnan Chang <changfengnan@bytedance.com>
[axboe: kill all remnants of task running, pointless now. massage message]
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 2c38ec93

block/blk-mq.c

+2 −10
Original line number Diff line number Diff line
@@ -5192,27 +5192,19 @@ EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues); 
static int blk_hctx_poll(struct request_queue *q, struct blk_mq_hw_ctx *hctx,

			 struct io_comp_batch *iob, unsigned int flags)

{

	long state = get_current_state();

	int ret;



	do {

		ret = q->mq_ops->poll(hctx, iob);

		if (ret > 0) {

			__set_current_state(TASK_RUNNING);

		if (ret > 0)

			return ret;

		}



		if (signal_pending_state(state, current))

			__set_current_state(TASK_RUNNING);

		if (task_is_running(current))

		if (task_sigpending(current))

			return 1;



		if (ret < 0 || (flags & BLK_POLL_ONESHOT))

			break;

		cpu_relax();

	} while (!need_resched());



	__set_current_state(TASK_RUNNING);

	return 0;

}