Make blk-mq handle the dma_drain_size field the same way as the old request path. Signed-off-by: Christoph Hellwig --- block/blk-mq.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/block/blk-mq.c b/block/blk-mq.c index 40fc4dd..35800e1 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -561,6 +561,16 @@ 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, -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/