[PATCH 7.2 1/2] blk-mq: introduce blk_rq_has_data()

[Caleb Sander Mateos <csander@purestorage.com>]

Add blk_rq_has_data(), an analogue of bio_has_data() for struct request.
This skips one dereference relative to bio_has_data(rq->bio).

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
---
 include/linux/blk-mq.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 18a2388ba581..4349aefdbc87 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -1102,10 +1102,11 @@ struct req_iterator {
 		 bio_iter_last(bvec, _iter.iter))
 
 /*
  * blk_rq_pos()			: the current sector
  * blk_rq_bytes()		: bytes left in the entire request
+ * blk_rq_has_data()		: whether the request carries data
  * blk_rq_cur_bytes()		: bytes left in the current segment
  * blk_rq_sectors()		: sectors left in the entire request
  * blk_rq_cur_sectors()		: sectors left in the current segment
  * blk_rq_stats_sectors()	: sectors of the entire request used for stats
  */
@@ -1117,10 +1118,18 @@ static inline sector_t blk_rq_pos(const struct request *rq)
 static inline unsigned int blk_rq_bytes(const struct request *rq)
 {
 	return rq->__data_len;
 }
 
+static inline bool blk_rq_has_data(const struct request *rq)
+{
+	return blk_rq_bytes(rq) &&
+	       req_op(rq) != REQ_OP_DISCARD &&
+	       req_op(rq) != REQ_OP_SECURE_ERASE &&
+	       req_op(rq) != REQ_OP_WRITE_ZEROES;
+}
+
 static inline int blk_rq_cur_bytes(const struct request *rq)
 {
 	if (!rq->bio)
 		return 0;
 	if (!bio_has_data(rq->bio))	/* dataless requests such as discard */
-- 
2.54.0