[PATCH 12/14] block: Don't merge requests if integrity flags differ

["Martin K. Petersen" <martin.petersen@oracle.com>]

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>
---
 block/blk-integrity.c  | 36 ++++++++++++++++++++++++++----------
 block/blk-merge.c      |  6 +++---
 include/linux/blkdev.h | 20 ++++++++++----------
 3 files changed, 39 insertions(+), 23 deletions(-)

diff --git a/block/blk-integrity.c b/block/blk-integrity.c
index 1c6ba442cd91..79ffb4855af0 100644
--- a/block/blk-integrity.c
+++ b/block/blk-integrity.c
@@ -186,37 +186,53 @@ int blk_integrity_compare(struct gendisk *gd1, struct gendisk *gd2)
 }
 EXPORT_SYMBOL(blk_integrity_compare);
 
-int blk_integrity_merge_rq(struct request_queue *q, struct request *req,
-			   struct request *next)
+bool blk_integrity_merge_rq(struct request_queue *q, struct request *req,
+			    struct request *next)
 {
-	if (blk_integrity_rq(req) != blk_integrity_rq(next))
-		return -1;
+	if (blk_integrity_rq(req) == 0 && blk_integrity_rq(next) == 0)
+		return true;
+
+	if (blk_integrity_rq(req) == 0 || blk_integrity_rq(next) == 0)
+		return false;
+
+	if (bio_integrity(req->bio)->bip_flags !=
+	    bio_integrity(next->bio)->bip_flags)
+		return false;
 
 	if (req->nr_integrity_segments + next->nr_integrity_segments >
 	    q->limits.max_integrity_segments)
-		return -1;
+		return false;
 
-	return 0;
+	return true;
 }
 EXPORT_SYMBOL(blk_integrity_merge_rq);
 
-int blk_integrity_merge_bio(struct request_queue *q, struct request *req,
-			    struct bio *bio)
+bool blk_integrity_merge_bio(struct request_queue *q, struct request *req,
+			     struct bio *bio)
 {
 	int nr_integrity_segs;
 	struct bio *next = bio->bi_next;
 
+	if (blk_integrity_rq(req) == 0 && bio_integrity(bio) == NULL)
+		return true;
+
+	if (blk_integrity_rq(req) == 0 || bio_integrity(bio) == NULL)
+		return false;
+
+	if (bio_integrity(req->bio)->bip_flags != bio_integrity(bio)->bip_flags)
+		return false;
+
 	bio->bi_next = NULL;
 	nr_integrity_segs = blk_rq_count_integrity_sg(q, bio);
 	bio->bi_next = next;
 
 	if (req->nr_integrity_segments + nr_integrity_segs >
 	    q->limits.max_integrity_segments)
-		return -1;
+		return false;
 
 	req->nr_integrity_segments += nr_integrity_segs;
 
-	return 0;
+	return true;
 }
 EXPORT_SYMBOL(blk_integrity_merge_bio);
 
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 54535831f1e1..20dcc7d0aa8f 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -308,7 +308,7 @@ static inline int ll_new_hw_segment(struct request_queue *q,
 	if (req->nr_phys_segments + nr_phys_segs > queue_max_segments(q))
 		goto no_merge;
 
-	if (bio_integrity(bio) && blk_integrity_merge_bio(q, req, bio))
+	if (blk_integrity_merge_bio(q, req, bio) == false)
 		goto no_merge;
 
 	/*
@@ -405,7 +405,7 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
 	if (total_phys_segments > queue_max_segments(q))
 		return 0;
 
-	if (blk_integrity_rq(req) && blk_integrity_merge_rq(q, req, next))
+	if (blk_integrity_merge_rq(q, req, next) == false)
 		return 0;
 
 	/* Merge is OK... */
@@ -585,7 +585,7 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
 		return false;
 
 	/* only merge integrity protected bio into ditto rq */
-	if (bio_integrity(bio) != blk_integrity_rq(rq))
+	if (blk_integrity_merge_bio(rq->q, rq, bio) == false)
 		return false;
 
 	/* must be using the same buffer */
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 68570d6cfec9..d2a0ba9a0487 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1501,10 +1501,10 @@ extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
 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)
@@ -1584,15 +1584,15 @@ static inline unsigned short queue_max_integrity_segments(struct request_queue *
 {
 	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;
 }
-- 
1.9.3