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>

6 files changed, 36 insertions, 27 deletions

diff --git a/Documentation/block/data-integrity.txt b/Documentation/block/data-integrity.txt
index b4eacf48053c..4d4de8b09530 100644
--- a/Documentation/block/data-integrity.txt
+++ b/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
diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 36b788552c3e..bd3125c3c124 100644
--- a/block/bio-integrity.c
+++ b/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);
diff --git a/drivers/scsi/sd_dif.c b/drivers/scsi/sd_dif.c
index a7a691d0af7d..29f0477a8708 100644
--- a/drivers/scsi/sd_dif.c
+++ b/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;
 
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,