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>

Documentation/block/data-integrity.txt

@@ -129,11 +129,11 @@ interface for this is being worked on.
 4.1 BIO
 
 The data integrity patches add a new field to struct bio when
-CONFIG_BLK_DEV_INTEGRITY is enabled.  bio->bi_integrity is a pointer
-to a struct bip which contains the bio integrity payload.  Essentially
-a bip is a trimmed down struct bio which holds a bio_vec containing
-the integrity metadata and the required housekeeping information (bvec
-pool, vector count, etc.)
+CONFIG_BLK_DEV_INTEGRITY is enabled.  bio_integrity(bio) returns a
+pointer to a struct bip which contains the bio integrity payload.
+Essentially a bip is a trimmed down struct bio which holds a bio_vec
+containing the integrity metadata and the required housekeeping
+information (bvec pool, vector count, etc.)
 
 A kernel subsystem can enable data integrity protection on a bio by
 calling bio_integrity_alloc(bio).  This will allocate and attach the

block/bio-integrity.c

@@ -79,6 +79,7 @@ struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
 	bip->bip_slab = idx;
 	bip->bip_bio = bio;
 	bio->bi_integrity = bip;
+	bio->bi_rw |= REQ_INTEGRITY;
 
 	return bip;
 err:
@@ -96,7 +97,7 @@ EXPORT_SYMBOL(bio_integrity_alloc);
  */
 void bio_integrity_free(struct bio *bio)
 {
-	struct bio_integrity_payload *bip = bio->bi_integrity;
+	struct bio_integrity_payload *bip = bio_integrity(bio);
 	struct bio_set *bs = bio->bi_pool;
 
 	if (bip->bip_owns_buf)
@@ -128,7 +129,7 @@ EXPORT_SYMBOL(bio_integrity_free);
 int bio_integrity_add_page(struct bio *bio, struct page *page,
 			   unsigned int len, unsigned int offset)
 {
-	struct bio_integrity_payload *bip = bio->bi_integrity;
+	struct bio_integrity_payload *bip = bio_integrity(bio);
 	struct bio_vec *iv;
 
 	if (bip->bip_vcnt >= bip->bip_max_vcnt) {
@@ -229,7 +230,7 @@ EXPORT_SYMBOL(bio_integrity_tag_size);
 static int bio_integrity_tag(struct bio *bio, void *tag_buf, unsigned int len,
 			     int set)
 {
-	struct bio_integrity_payload *bip = bio->bi_integrity;
+	struct bio_integrity_payload *bip = bio_integrity(bio);
 	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
 	unsigned int nr_sectors;
 
@@ -304,12 +305,12 @@ static int bio_integrity_generate_verify(struct bio *bio, int operate)
 	struct bio_vec *bv;
 	sector_t sector;
 	unsigned int sectors, ret = 0, i;
-	void *prot_buf = bio->bi_integrity->bip_buf;
+	void *prot_buf = bio_integrity(bio)->bip_buf;
 
 	if (operate)
 		sector = bio->bi_iter.bi_sector;
 	else
-		sector = bio->bi_integrity->bip_iter.bi_sector;
+		sector = bio_integrity(bio)->bip_iter.bi_sector;
 
 	bix.disk_name = bio->bi_bdev->bd_disk->disk_name;
 	bix.sector_size = bi->sector_size;
@@ -505,7 +506,7 @@ static void bio_integrity_verify_fn(struct work_struct *work)
  */
 void bio_integrity_endio(struct bio *bio, int error)
 {
-	struct bio_integrity_payload *bip = bio->bi_integrity;
+	struct bio_integrity_payload *bip = bio_integrity(bio);
 
 	BUG_ON(bip->bip_bio != bio);
 
@@ -536,7 +537,7 @@ EXPORT_SYMBOL(bio_integrity_endio);
  */
 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
 {
-	struct bio_integrity_payload *bip = bio->bi_integrity;
+	struct bio_integrity_payload *bip = bio_integrity(bio);
 	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
 	unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
 
@@ -558,7 +559,7 @@ EXPORT_SYMBOL(bio_integrity_advance);
 void bio_integrity_trim(struct bio *bio, unsigned int offset,
 			unsigned int sectors)
 {
-	struct bio_integrity_payload *bip = bio->bi_integrity;
+	struct bio_integrity_payload *bip = bio_integrity(bio);
 	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
 
 	bio_integrity_advance(bio, offset << 9);
@@ -577,7 +578,7 @@ EXPORT_SYMBOL(bio_integrity_trim);
 int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 			gfp_t gfp_mask)
 {
-	struct bio_integrity_payload *bip_src = bio_src->bi_integrity;
+	struct bio_integrity_payload *bip_src = bio_integrity(bio_src);
 	struct bio_integrity_payload *bip;
 
 	BUG_ON(bip_src == NULL);

drivers/scsi/sd_dif.c

@@ -383,9 +383,9 @@ void sd_dif_prepare(struct request *rq, sector_t hw_sector,
 		if (bio_flagged(bio, BIO_MAPPED_INTEGRITY))
 			break;
 
-		virt = bio->bi_integrity->bip_iter.bi_sector & 0xffffffff;
+		virt = bio_integrity(bio)->bip_iter.bi_sector & 0xffffffff;
 
-		bip_for_each_vec(iv, bio->bi_integrity, iter) {
+		bip_for_each_vec(iv, bio_integrity(bio), iter) {
 			sdt = kmap_atomic(iv.bv_page)
 				+ iv.bv_offset;
 
@@ -434,9 +434,9 @@ void sd_dif_complete(struct scsi_cmnd *scmd, unsigned int good_bytes)
 		struct bio_vec iv;
 		struct bvec_iter iter;
 
-		virt = bio->bi_integrity->bip_iter.bi_sector & 0xffffffff;
+		virt = bio_integrity(bio)->bip_iter.bi_sector & 0xffffffff;
 
-		bip_for_each_vec(iv, bio->bi_integrity, iter) {
+		bip_for_each_vec(iv, bio_integrity(bio), iter) {
 			sdt = kmap_atomic(iv.bv_page)
 				+ iv.bv_offset;
 

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);

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)

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,