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>
This commit is contained in:
Christoph Hellwig 2017-01-13 12:29:10 +01:00 committed by Jens Axboe
parent f99e86485c
commit 2e3258ecfa

View File

@ -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)
{