blk-mq: ensure mq_ops ->poll() is entered at least once (aa61bec3) · Commits · 戴 / test

Right now we immediately bail if need_resched() is true, but we need to do at least one loop in case we have entries waiting. So just invert the need_resched() check, putting it at the bottom of the loop. Reviewed-by:

Christoph Hellwig <hch@lst.de> Signed-off-by:

Jens Axboe <axboe@kernel.dk>

block/blk-mq.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -3375,7 +3375,7 @@ static int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
		hctx->poll_considered++;

		state = current->state;
		while (!need_resched()) {
		do {
		int ret;

		hctx->poll_invoked++;
		@@ -3395,7 +3395,7 @@ static int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
		if (ret < 0 \|\| !spin)
		break;
		cpu_relax();
		}
		} while (!need_resched());

		__set_current_state(TASK_RUNNING);
		return 0;

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