1 files changed, 41 insertions, 104 deletions

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 5efc9e7a68b7..8681cd6f9911 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -11,7 +11,7 @@
 
 void blk_recalc_rq_sectors(struct request *rq, int nsect)
 {
-        if (blk_fs_request(rq)) {
+        if (blk_fs_request(rq) || blk_discard_rq(rq)) {
                 rq->hard_sector += nsect;
                 rq->hard_nr_sectors -= nsect;
 
@@ -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
@@ -66,7 +63,7 @@ void blk_recalc_rq_segments(struct request *rq)
                  */
                 high = page_to_pfn(bv->bv_page) > q->bounce_pfn;
                 if (high || highprv)
-                        goto new_hw_segment;
+                        goto new_segment;
                 if (cluster) {
                         if (seg_size + bv->bv_len > q->max_segment_size)
                                 goto new_segment;
@@ -74,26 +71,14 @@ void blk_recalc_rq_segments(struct request *rq)
                                 goto new_segment;
                         if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bv))
                                 goto new_segment;
-                        if (BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len))
-                                goto new_hw_segment;
 
                         seg_size += bv->bv_len;
-                        hw_seg_size += bv->bv_len;
                         bvprv = bv;
                         continue;
                 }
 new_segment:
-                if (BIOVEC_VIRT_MERGEABLE(bvprv, bv) &&
-                    !BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len))
-                        hw_seg_size += bv->bv_len;
-                else {
-new_hw_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 = BIOVEC_VIRT_START_SIZE(bv) + bv->bv_len;
-                        nr_hw_segs++;
-                }
+                if (nr_phys_segs == 1 && seg_size > rq->bio->bi_seg_front_size)
+                        rq->bio->bi_seg_front_size = seg_size;
 
                 nr_phys_segs++;
                 bvprv = bv;
@@ -101,13 +86,12 @@ new_hw_segment:
                 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;
+        if (nr_phys_segs == 1 && seg_size > rq->bio->bi_seg_front_size)
+                rq->bio->bi_seg_front_size = seg_size;
+        if (seg_size > rq->biotail->bi_seg_back_size)
+                rq->biotail->bi_seg_back_size = 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)
@@ -120,7 +104,6 @@ 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);
@@ -131,13 +114,18 @@ static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio,
         if (!test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags))
                 return 0;
 
-        if (!BIOVEC_PHYS_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)))
+        if (bio->bi_seg_back_size + nxt->bi_seg_front_size >
+            q->max_segment_size)
                 return 0;
-        if (bio->bi_size + nxt->bi_size > q->max_segment_size)
+
+        if (!bio_has_data(bio))
+                return 1;
+
+        if (!BIOVEC_PHYS_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)))
                 return 0;
 
         /*
-         * bio and nxt are contigous in memory, check if the queue allows
+         * bio and nxt are contiguous in memory; check if the queue allows
          * these two to be merged into one
          */
         if (BIO_SEG_BOUNDARY(q, bio, nxt))
@@ -146,22 +134,6 @@ static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio,
         return 0;
 }
 
-static int blk_hw_contig_segment(struct request_queue *q, struct bio *bio,
-                                 struct bio *nxt)
-{
-        if (!bio_flagged(bio, BIO_SEG_VALID))
-                blk_recount_segments(q, bio);
-        if (!bio_flagged(nxt, BIO_SEG_VALID))
-                blk_recount_segments(q, nxt);
-        if (!BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)) ||
-            BIOVEC_VIRT_OVERSIZE(bio->bi_hw_back_size + nxt->bi_hw_front_size))
-                return 0;
-        if (bio->bi_hw_back_size + nxt->bi_hw_front_size > q->max_segment_size)
-                return 0;
-
-        return 1;
-}
-
 /*
  * map a request to scatterlist, return number of sg entries setup. Caller
  * must make sure sg can hold rq->nr_phys_segments entries
@@ -275,10 +247,9 @@ 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)
@@ -290,7 +261,6 @@ 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;
 }
@@ -299,7 +269,6 @@ int ll_back_merge_fn(struct request_queue *q, struct request *req,
                      struct bio *bio)
 {
         unsigned short max_sectors;
-        int len;
 
         if (unlikely(blk_pc_request(req)))
                 max_sectors = q->max_hw_sectors;
@@ -316,19 +285,6 @@ int ll_back_merge_fn(struct request_queue *q, struct request *req,
                 blk_recount_segments(q, req->biotail);
         if (!bio_flagged(bio, BIO_SEG_VALID))
                 blk_recount_segments(q, bio);
-        len = req->biotail->bi_hw_back_size + bio->bi_hw_front_size;
-        if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(req->biotail), __BVEC_START(bio))
-            && !BIOVEC_VIRT_OVERSIZE(len)) {
-                int mergeable =  ll_new_mergeable(q, req, bio);
-
-                if (mergeable) {
-                        if (req->nr_hw_segments == 1)
-                                req->bio->bi_hw_front_size = len;
-                        if (bio->bi_hw_segments == 1)
-                                bio->bi_hw_back_size = len;
-                }
-                return mergeable;
-        }
 
         return ll_new_hw_segment(q, req, bio);
 }
@@ -337,7 +293,6 @@ int ll_front_merge_fn(struct request_queue *q, struct request *req,
                       struct bio *bio)
 {
         unsigned short max_sectors;
-        int len;
 
         if (unlikely(blk_pc_request(req)))
                 max_sectors = q->max_hw_sectors;
@@ -351,23 +306,10 @@ int ll_front_merge_fn(struct request_queue *q, struct request *req,
                         q->last_merge = NULL;
                 return 0;
         }
-        len = bio->bi_hw_back_size + req->bio->bi_hw_front_size;
         if (!bio_flagged(bio, BIO_SEG_VALID))
                 blk_recount_segments(q, bio);
         if (!bio_flagged(req->bio, BIO_SEG_VALID))
                 blk_recount_segments(q, req->bio);
-        if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(req->bio)) &&
-            !BIOVEC_VIRT_OVERSIZE(len)) {
-                int mergeable =  ll_new_mergeable(q, req, bio);
-
-                if (mergeable) {
-                        if (bio->bi_hw_segments == 1)
-                                bio->bi_hw_front_size = len;
-                        if (req->nr_hw_segments == 1)
-                                req->biotail->bi_hw_back_size = len;
-                }
-                return mergeable;
-        }
 
         return ll_new_hw_segment(q, req, bio);
 }
@@ -376,7 +318,8 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
                                 struct request *next)
 {
         int total_phys_segments;
-        int total_hw_segments;
+        unsigned int seg_size =
+                req->biotail->bi_seg_back_size + next->bio->bi_seg_front_size;
 
         /*
          * First check if the either of the requests are re-queued
@@ -392,32 +335,22 @@ 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 (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;
                 total_phys_segments--;
+        }
 
         if (total_phys_segments > q->max_phys_segments)
                 return 0;
 
-        total_hw_segments = req->nr_hw_segments + next->nr_hw_segments;
-        if (blk_hw_contig_segment(q, req->biotail, next->bio)) {
-                int len = req->biotail->bi_hw_back_size +
-                                next->bio->bi_hw_front_size;
-                /*
-                 * propagate the combined length to the end of the requests
-                 */
-                if (req->nr_hw_segments == 1)
-                        req->bio->bi_hw_front_size = len;
-                if (next->nr_hw_segments == 1)
-                        next->biotail->bi_hw_back_size = len;
-                total_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;
 }
 
@@ -470,17 +403,21 @@ static int attempt_merge(struct request_queue *q, struct request *req,
         elv_merge_requests(q, req, next);
 
         if (req->rq_disk) {
-                struct hd_struct *part
-                        = get_part(req->rq_disk, req->sector);
-                disk_round_stats(req->rq_disk);
-                req->rq_disk->in_flight--;
-                if (part) {
-                        part_round_stats(part);
-                        part->in_flight--;
-                }
+                struct hd_struct *part;
+                int cpu;
+
+                cpu = part_stat_lock();
+                part = disk_map_sector_rcu(req->rq_disk, req->sector);
+
+                part_round_stats(cpu, part);
+                part_dec_in_flight(part);
+
+                part_stat_unlock();
         }
 
         req->ioprio = ioprio_best(req->ioprio, next->ioprio);
+        if (blk_rq_cpu_valid(next))
+                req->cpu = next->cpu;
 
         __blk_put_request(q, next);
         return 1;