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authorChristoph Hellwig <hch@lst.de>2017-01-13 12:29:10 +0100
committerJens Axboe <axboe@fb.com>2017-01-13 15:17:04 -0700
commit2e3258ecfaebace1ceffaa14e0ea94775d54f46f (patch)
treefd42995d3a8f5f5cf9106629e85d4144d9379a74
parentf99e86485cc32cd16e5cc97f9bb0474f28608d84 (diff)
block: add blk_rq_payload_bytes
Add a helper to calculate the actual data transfer size for special payload requests. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
-rw-r--r--include/linux/blkdev.h13
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ff3d774f2751..1ca8e8fd1078 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1000,6 +1000,19 @@ static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
return blk_rq_cur_bytes(rq) >> 9;
}
+/*
+ * Some commands like WRITE SAME have a payload or data transfer size which
+ * is different from the size of the request. Any driver that supports such
+ * commands using the RQF_SPECIAL_PAYLOAD flag needs to use this helper to
+ * calculate the data transfer size.
+ */
+static inline unsigned int blk_rq_payload_bytes(struct request *rq)
+{
+ if (rq->rq_flags & RQF_SPECIAL_PAYLOAD)
+ return rq->special_vec.bv_len;
+ return blk_rq_bytes(rq);
+}
+
static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q,
int op)
{