Commit 4f7f418c authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
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blk-mq: handle dma_drain_size 



Make blk-mq handle the dma_drain_size field the same way as the old request
path.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 6f5ba581

block/blk-mq.c

+10 −0
Original line number Diff line number Diff line
@@ -582,6 +582,16 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) 
		list_del_init(&rq->queuelist);

		blk_mq_start_request(rq);



		if (q->dma_drain_size && blk_rq_bytes(rq)) {

			/*

			 * make sure space for the drain appears we

			 * know we can do this because max_hw_segments

			 * has been adjusted to be one fewer than the

			 * device can handle

			 */

			rq->nr_phys_segments++;

		}



		/*

		 * Last request in the series. Flag it as such, this

		 * enables drivers to know when IO should be kicked off,