From 4f7f418c4835d3ce1b66d00502df41f324d13ec0 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 7 Feb 2014 10:22:38 -0800 Subject: 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: Christoph Hellwig Signed-off-by: Jens Axboe --- block/blk-mq.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'block') diff --git a/block/blk-mq.c b/block/blk-mq.c index c9306e3..a99bea4 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -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, -- cgit v1.1