block: Replace bi_integrity with bi_special

For commands like REQ_COPY we need a way to pass extra information along
with each bio. Like integrity metadata this information must be
available at the bottom of the stack so bi_private does not suffice.

Rename the existing bi_integrity field to bi_special and make it a union
so we can have different bio extensions for each class of command.

We previously used bi_integrity != NULL as a way to identify whether a
bio had integrity metadata or not. Introduce a REQ_INTEGRITY to be the
indicator now that bi_special can contain different things.

In addition, bio_integrity(bio) will now return a pointer to the
integrity payload (when applicable).

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>

3 files changed, 17 insertions, 9 deletions

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 63e399b4fde5..a810a74071b2 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -293,6 +293,15 @@ static inline unsigned bio_segments(struct bio *bio)
 #define bio_get(bio)	atomic_inc(&(bio)->bi_cnt)
 
 #if defined(CONFIG_BLK_DEV_INTEGRITY)
+
+static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
+{
+	if (bio->bi_rw & REQ_INTEGRITY)
+		return bio->bi_integrity;
+
+	return NULL;
+}
+
 /*
  * bio integrity payload
  */
@@ -661,8 +670,6 @@ struct biovec_slab {
 	for_each_bio(_bio)						\
 		bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 
-#define bio_integrity(bio) (bio->bi_integrity != NULL)
-
 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 extern void bio_integrity_free(struct bio *);
 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index bb7d66460e7a..6a5d2f2de1b9 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -78,9 +78,11 @@ struct bio {
 	struct io_context	*bi_ioc;
 	struct cgroup_subsys_state *bi_css;
 #endif
+	union {
 #if defined(CONFIG_BLK_DEV_INTEGRITY)
-	struct bio_integrity_payload *bi_integrity;  /* data integrity */
+		struct bio_integrity_payload *bi_integrity; /* data integrity */
 #endif
+	};
 
 	unsigned short		bi_vcnt;	/* how many bio_vec's */
 
@@ -162,6 +164,7 @@ enum rq_flag_bits {
 	__REQ_WRITE_SAME,	/* write same block many times */
 
 	__REQ_NOIDLE,		/* don't anticipate more IO after this one */
+	__REQ_INTEGRITY,	/* I/O includes block integrity payload */
 	__REQ_FUA,		/* forced unit access */
 	__REQ_FLUSH,		/* request for cache flush */
 
@@ -203,13 +206,14 @@ enum rq_flag_bits {
 #define REQ_DISCARD		(1ULL << __REQ_DISCARD)
 #define REQ_WRITE_SAME		(1ULL << __REQ_WRITE_SAME)
 #define REQ_NOIDLE		(1ULL << __REQ_NOIDLE)
+#define REQ_INTEGRITY		(1ULL << __REQ_INTEGRITY)
 
 #define REQ_FAILFAST_MASK \
 	(REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
 #define REQ_COMMON_MASK \
 	(REQ_WRITE | REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_PRIO | \
 	 REQ_DISCARD | REQ_WRITE_SAME | REQ_NOIDLE | REQ_FLUSH | REQ_FUA | \
-	 REQ_SECURE)
+	 REQ_SECURE | REQ_INTEGRITY)
 #define REQ_CLONE_MASK		REQ_COMMON_MASK
 
 #define BIO_NO_ADVANCE_ITER_MASK	(REQ_DISCARD|REQ_WRITE_SAME)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 49f3461e4272..7fcb2caef559 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1514,12 +1514,9 @@ static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
 	return disk->integrity;
 }
 
-static inline int blk_integrity_rq(struct request *rq)
+static inline bool blk_integrity_rq(struct request *rq)
 {
-	if (rq->bio == NULL)
-		return 0;
-
-	return bio_integrity(rq->bio);
+	return rq->cmd_flags & REQ_INTEGRITY;
 }
 
 static inline void blk_queue_max_integrity_segments(struct request_queue *q,