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>

diff --git a/block/blk-merge.c b/block/blk-merge.c
index eee2c02..17713d7 100644 (file)
--- 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;
 

diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index be41827..95202f8 100644 (file)
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -159,13 +159,6 @@ struct bio {
         */
        unsigned int            bi_phys_segments;
 
-       /*
-        * To keep track of the max segment size, we account for the
-        * sizes of the first and last mergeable segments in this bio.
-        */
-       unsigned int            bi_seg_front_size;
-       unsigned int            bi_seg_back_size;
-
        struct bvec_iter        bi_iter;
 
        atomic_t                __bi_remaining;