drop vmerge accounting

Remove hw_segments field from struct bio and struct request. Without virtual
merge accounting they have no purpose.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

3 files changed, 4 insertions, 30 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 1261516dd42..2616cdd049a 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2026,7 +2026,6 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
 
         if (bio_has_data(bio)) {
                 rq->nr_phys_segments = bio_phys_segments(q, bio);
-                rq->nr_hw_segments = bio_hw_segments(q, bio);
                 rq->buffer = bio_data(bio);
         }
         rq->current_nr_sectors = bio_cur_sectors(bio);
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 2c2a2ee716e..d81d91419ff 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -41,12 +41,9 @@ void blk_recalc_rq_sectors(struct request *rq, int nsect)
 void blk_recalc_rq_segments(struct request *rq)
 {
         int nr_phys_segs;
-        int nr_hw_segs;
         unsigned int phys_size;
-        unsigned int hw_size;
         struct bio_vec *bv, *bvprv = NULL;
         int seg_size;
-        int hw_seg_size;
         int cluster;
         struct req_iterator iter;
         int high, highprv = 1;
@@ -56,8 +53,8 @@ void blk_recalc_rq_segments(struct request *rq)
                 return;
 
         cluster = test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
-        hw_seg_size = seg_size = 0;
-        phys_size = hw_size = nr_phys_segs = nr_hw_segs = 0;
+        seg_size = 0;
+        phys_size = nr_phys_segs = 0;
         rq_for_each_segment(bv, rq, iter) {
                 /*
                  * the trick here is making sure that a high page is never
@@ -76,30 +73,17 @@ void blk_recalc_rq_segments(struct request *rq)
                                 goto new_segment;
 
                         seg_size += bv->bv_len;
-                        hw_seg_size += bv->bv_len;
                         bvprv = bv;
                         continue;
                 }
 new_segment:
-                if (nr_hw_segs == 1 &&
-                    hw_seg_size > rq->bio->bi_hw_front_size)
-                        rq->bio->bi_hw_front_size = hw_seg_size;
-                hw_seg_size = bv->bv_len;
-                nr_hw_segs++;
-
                 nr_phys_segs++;
                 bvprv = bv;
                 seg_size = bv->bv_len;
                 highprv = high;
         }
 
-        if (nr_hw_segs == 1 &&
-            hw_seg_size > rq->bio->bi_hw_front_size)
-                rq->bio->bi_hw_front_size = hw_seg_size;
-        if (hw_seg_size > rq->biotail->bi_hw_back_size)
-                rq->biotail->bi_hw_back_size = hw_seg_size;
         rq->nr_phys_segments = nr_phys_segs;
-        rq->nr_hw_segments = nr_hw_segs;
 }
 
 void blk_recount_segments(struct request_queue *q, struct bio *bio)
@@ -112,7 +96,6 @@ void blk_recount_segments(struct request_queue *q, struct bio *bio)
         blk_recalc_rq_segments(&rq);
         bio->bi_next = nxt;
         bio->bi_phys_segments = rq.nr_phys_segments;
-        bio->bi_hw_segments = rq.nr_hw_segments;
         bio->bi_flags |= (1 << BIO_SEG_VALID);
 }
 EXPORT_SYMBOL(blk_recount_segments);
@@ -255,10 +238,9 @@ static inline int ll_new_hw_segment(struct request_queue *q,
                                     struct request *req,
                                     struct bio *bio)
 {
-        int nr_hw_segs = bio_hw_segments(q, bio);
         int nr_phys_segs = bio_phys_segments(q, bio);
 
-        if (req->nr_hw_segments + nr_hw_segs > q->max_hw_segments
+        if (req->nr_phys_segments + nr_phys_segs > q->max_hw_segments
             || req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) {
                 req->cmd_flags |= REQ_NOMERGE;
                 if (req == q->last_merge)
@@ -270,7 +252,6 @@ static inline int ll_new_hw_segment(struct request_queue *q,
          * This will form the start of a new hw segment.  Bump both
          * counters.
          */
-        req->nr_hw_segments += nr_hw_segs;
         req->nr_phys_segments += nr_phys_segs;
         return 1;
 }
@@ -328,7 +309,6 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
                                 struct request *next)
 {
         int total_phys_segments;
-        int total_hw_segments;
 
         /*
          * First check if the either of the requests are re-queued
@@ -350,14 +330,11 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
         if (total_phys_segments > q->max_phys_segments)
                 return 0;
 
-        total_hw_segments = req->nr_hw_segments + next->nr_hw_segments;
-
-        if (total_hw_segments > q->max_hw_segments)
+        if (total_phys_segments > q->max_hw_segments)
                 return 0;
 
         /* Merge is OK... */
         req->nr_phys_segments = total_phys_segments;
-        req->nr_hw_segments = total_hw_segments;
         return 1;
 }
 
diff --git a/block/elevator.c b/block/elevator.c
index 4f5127054e3..269615e6dbf 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -790,7 +790,6 @@ struct request *elv_next_request(struct request_queue *q)
                          * device can handle
                          */
                         rq->nr_phys_segments++;
-                        rq->nr_hw_segments++;
                 }
 
                 if (!q->prep_rq_fn)
@@ -813,7 +812,6 @@ struct request *elv_next_request(struct request_queue *q)
                                  * so that we don't add it again
                                  */
                                 --rq->nr_phys_segments;
-                                --rq->nr_hw_segments;
                         }
 
                         rq = NULL;