block: remove the bi_seg_{front,back}_size fields in struct bio

At this point these fields aren't used for anything, so we can remove
them.

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 12 insertions, 82 deletions

diff --git a/block/blk-merge.c b/block/blk-merge.c
index eee2c02c50ce..17713d7d98d5 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -162,8 +162,7 @@ static unsigned get_max_segment_size(struct request_queue *q,
  * variables.
  */
 static bool bvec_split_segs(struct request_queue *q, struct bio_vec *bv,
-                unsigned *nsegs, unsigned *last_seg_size,
-                unsigned *front_seg_size, unsigned *sectors, unsigned max_segs)
+                unsigned *nsegs, unsigned *sectors, unsigned max_segs)
 {
         unsigned len = bv->bv_len;
         unsigned total_len = 0;
@@ -185,28 +184,12 @@ static bool bvec_split_segs(struct request_queue *q, struct bio_vec *bv,
                         break;
         }
 
-        if (!new_nsegs)
-                return !!len;
-
-        /* update front segment size */
-        if (!*nsegs) {
-                unsigned first_seg_size;
-
-                if (new_nsegs == 1)
-                        first_seg_size = get_max_segment_size(q, bv->bv_offset);
-                else
-                        first_seg_size = queue_max_segment_size(q);
-
-                if (*front_seg_size < first_seg_size)
-                        *front_seg_size = first_seg_size;
+        if (new_nsegs) {
+                *nsegs += new_nsegs;
+                if (sectors)
+                        *sectors += total_len >> 9;
         }
 
-        /* update other varibles */
-        *last_seg_size = seg_size;
-        *nsegs += new_nsegs;
-        if (sectors)
-                *sectors += total_len >> 9;
-
         /* split in the middle of the bvec if len != 0 */
         return !!len;
 }
@@ -218,8 +201,7 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
 {
         struct bio_vec bv, bvprv, *bvprvp = NULL;
         struct bvec_iter iter;
-        unsigned seg_size = 0, nsegs = 0, sectors = 0;
-        unsigned front_seg_size = bio->bi_seg_front_size;
+        unsigned nsegs = 0, sectors = 0;
         bool do_split = true;
         struct bio *new = NULL;
         const unsigned max_sectors = get_max_io_size(q, bio);
@@ -243,8 +225,6 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
                                 /* split in the middle of bvec */
                                 bv.bv_len = (max_sectors - sectors) << 9;
                                 bvec_split_segs(q, &bv, &nsegs,
-                                                &seg_size,
-                                                &front_seg_size,
                                                 &sectors, max_segs);
                         }
                         goto split;
@@ -258,12 +238,9 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
 
                 if (bv.bv_offset + bv.bv_len <= PAGE_SIZE) {
                         nsegs++;
-                        seg_size = bv.bv_len;
                         sectors += bv.bv_len >> 9;
-                        if (nsegs == 1 && seg_size > front_seg_size)
-                                front_seg_size = seg_size;
-                } else if (bvec_split_segs(q, &bv, &nsegs, &seg_size,
-                                    &front_seg_size, &sectors, max_segs)) {
+                } else if (bvec_split_segs(q, &bv, &nsegs, &sectors,
+                                max_segs)) {
                         goto split;
                 }
         }
@@ -278,10 +255,6 @@ split:
                         bio = new;
         }
 
-        bio->bi_seg_front_size = front_seg_size;
-        if (seg_size > bio->bi_seg_back_size)
-                bio->bi_seg_back_size = seg_size;
-
         return do_split ? new : NULL;
 }
 
@@ -336,17 +309,13 @@ EXPORT_SYMBOL(blk_queue_split);
 static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
                                              struct bio *bio)
 {
-        struct bio_vec uninitialized_var(bv), bvprv = { NULL };
-        unsigned int seg_size, nr_phys_segs;
-        unsigned front_seg_size;
-        struct bio *fbio, *bbio;
+        unsigned int nr_phys_segs = 0;
         struct bvec_iter iter;
+        struct bio_vec bv;
 
         if (!bio)
                 return 0;
 
-        front_seg_size = bio->bi_seg_front_size;
-
         switch (bio_op(bio)) {
         case REQ_OP_DISCARD:
         case REQ_OP_SECURE_ERASE:
@@ -356,23 +325,11 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
                 return 1;
         }
 
-        fbio = bio;
-        seg_size = 0;
-        nr_phys_segs = 0;
         for_each_bio(bio) {
-                bio_for_each_bvec(bv, bio, iter) {
-                        bvec_split_segs(q, &bv, &nr_phys_segs, &seg_size,
-                                        &front_seg_size, NULL, UINT_MAX);
-                }
-                bbio = bio;
-                if (likely(bio->bi_iter.bi_size))
-                        bvprv = bv;
+                bio_for_each_bvec(bv, bio, iter)
+                        bvec_split_segs(q, &bv, &nr_phys_segs, NULL, UINT_MAX);
         }
 
-        fbio->bi_seg_front_size = front_seg_size;
-        if (seg_size > bbio->bi_seg_back_size)
-                bbio->bi_seg_back_size = seg_size;
-
         return nr_phys_segs;
 }
 
@@ -392,24 +349,6 @@ void blk_recount_segments(struct request_queue *q, struct bio *bio)
         bio_set_flag(bio, BIO_SEG_VALID);
 }
 
-static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio,
-                                   struct bio *nxt)
-{
-        struct bio_vec end_bv = { NULL }, nxt_bv;
-
-        if (bio->bi_seg_back_size + nxt->bi_seg_front_size >
-            queue_max_segment_size(q))
-                return 0;
-
-        if (!bio_has_data(bio))
-                return 1;
-
-        bio_get_last_bvec(bio, &end_bv);
-        bio_get_first_bvec(nxt, &nxt_bv);
-
-        return biovec_phys_mergeable(q, &end_bv, &nxt_bv);
-}
-
 static inline struct scatterlist *blk_next_sg(struct scatterlist **sg,
                 struct scatterlist *sglist)
 {
@@ -669,8 +608,6 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
                                 struct request *next)
 {
         int total_phys_segments;
-        unsigned int seg_size =
-                req->biotail->bi_seg_back_size + next->bio->bi_seg_front_size;
 
         if (req_gap_back_merge(req, next->bio))
                 return 0;
@@ -683,13 +620,6 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
                 return 0;
 
         total_phys_segments = req->nr_phys_segments + next->nr_phys_segments;
-        if (blk_phys_contig_segment(q, req->biotail, next->bio)) {
-                if (req->nr_phys_segments == 1)
-                        req->bio->bi_seg_front_size = seg_size;
-                if (next->nr_phys_segments == 1)
-                        next->biotail->bi_seg_back_size = seg_size;
-        }
-
         if (total_phys_segments > queue_max_segments(q))
                 return 0;