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authorChristoph Hellwig <hch@infradead.org>2014-02-07 10:22:38 -0800
committerJens Axboe <axboe@fb.com>2014-02-07 11:58:54 -0700
commit4f7f418c4835d3ce1b66d00502df41f324d13ec0 (patch)
treeab5cd97067a6bf0350e639da9e0df8c7c1369652 /block
parent6f5ba581c0d3ba0a76fe138123c1c2817ffcbeb1 (diff)
downloadlinux-linaro-stable-4f7f418c4835d3ce1b66d00502df41f324d13ec0.tar.gz
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 <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index c9306e3403fe..a99bea455452 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,