From 2e3258ecfaebace1ceffaa14e0ea94775d54f46f Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 13 Jan 2017 12:29:10 +0100 Subject: [PATCH] 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 Reviewed-by: Hannes Reinecke Signed-off-by: Jens Axboe --- include/linux/blkdev.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) 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) { -- 2.39.5