block: remove the bi_phys_segments field in struct bio

We only need the number of segments in the blk-mq submission path.
Remove the field from struct bio, and return it from a variant of
blk_queue_split instead of that it can passed as an argument to
those functions that need the value.

This also means we stop recounting segments except for cloning
and partial segments.

To keep the number of arguments in this how path down remove
pointless struct request_queue arguments from any of the functions
that had it and grew a nr_segs argument.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

5 files changed, 2 insertions, 10 deletions

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 0f23b5682640..ee11c4324751 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -408,7 +408,6 @@ static inline void bio_wouldblock_error(struct bio *bio)
 }
 
 struct request_queue;
-extern int bio_phys_segments(struct request_queue *, struct bio *);
 
 extern int submit_bio_wait(struct bio *bio);
 extern void bio_advance(struct bio *, unsigned);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 15d1aa53d96c..3fa1fa59f9b2 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -306,7 +306,7 @@ void blk_mq_delay_kick_requeue_list(struct request_queue *q, unsigned long msecs
 bool blk_mq_complete_request(struct request *rq);
 void blk_mq_complete_request_sync(struct request *rq);
 bool blk_mq_bio_list_merge(struct request_queue *q, struct list_head *list,
-			   struct bio *bio);
+			   struct bio *bio, unsigned int nr_segs);
 bool blk_mq_queue_stopped(struct request_queue *q);
 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx);
 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 95202f80676c..6a53799c3fe2 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -154,11 +154,6 @@ struct bio {
 	blk_status_t		bi_status;
 	u8			bi_partno;
 
-	/* Number of segments in this BIO after
-	 * physical address coalescing is performed.
-	 */
-	unsigned int		bi_phys_segments;
-
 	struct bvec_iter	bi_iter;
 
 	atomic_t		__bi_remaining;
@@ -210,7 +205,6 @@ struct bio {
  */
 enum {
 	BIO_NO_PAGE_REF,	/* don't put release vec pages */
-	BIO_SEG_VALID,		/* bi_phys_segments valid */
 	BIO_CLONED,		/* doesn't own data */
 	BIO_BOUNCED,		/* bio is a bounce bio */
 	BIO_USER_MAPPED,	/* contains user pages */
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 2d4dfe82767a..d5d3bb45dfb6 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -841,7 +841,6 @@ extern blk_status_t blk_insert_cloned_request(struct request_queue *q,
 				     struct request *rq);
 extern int blk_rq_append_bio(struct request *rq, struct bio **bio);
 extern void blk_queue_split(struct request_queue *, struct bio **);
-extern void blk_recount_segments(struct request_queue *, struct bio *);
 extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
 extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
 			      unsigned int, void __user *);
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index 6e8bc53740f0..169bb2e02516 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -34,7 +34,7 @@ struct elevator_mq_ops {
 	void (*depth_updated)(struct blk_mq_hw_ctx *);
 
 	bool (*allow_merge)(struct request_queue *, struct request *, struct bio *);
-	bool (*bio_merge)(struct blk_mq_hw_ctx *, struct bio *);
+	bool (*bio_merge)(struct blk_mq_hw_ctx *, struct bio *, unsigned int);
 	int (*request_merge)(struct request_queue *q, struct request **, struct bio *);
 	void (*request_merged)(struct request_queue *, struct request *, enum elv_merge);
 	void (*requests_merged)(struct request_queue *, struct request *, struct request *);