block: Don't merge requests if integrity flags differ

We'd occasionally merge requests with conflicting integrity flags.
Introduce a merge helper which checks that the requests have compatible
integrity payloads.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 773df19..038b40f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1497,10 +1497,10 @@
 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
 				   struct scatterlist *);
 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
-extern int blk_integrity_merge_rq(struct request_queue *, struct request *,
-				  struct request *);
-extern int blk_integrity_merge_bio(struct request_queue *, struct request *,
-				   struct bio *);
+extern bool blk_integrity_merge_rq(struct request_queue *, struct request *,
+				   struct request *);
+extern bool blk_integrity_merge_bio(struct request_queue *, struct request *,
+				    struct bio *);
 
 static inline
 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
@@ -1580,15 +1580,15 @@
 {
 	return 0;
 }
-static inline int blk_integrity_merge_rq(struct request_queue *rq,
-					 struct request *r1,
-					 struct request *r2)
+static inline bool blk_integrity_merge_rq(struct request_queue *rq,
+					  struct request *r1,
+					  struct request *r2)
 {
 	return 0;
 }
-static inline int blk_integrity_merge_bio(struct request_queue *rq,
-					  struct request *r,
-					  struct bio *b)
+static inline bool blk_integrity_merge_bio(struct request_queue *rq,
+					   struct request *r,
+					   struct bio *b)
 {
 	return 0;
 }