1 files changed, 31 insertions, 12 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index d67c95ef8d7e..2b53c3841b53 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1320,7 +1320,7 @@ static int clone_bio(struct dm_target_io *tio, struct bio *bio,
 
         __bio_clone_fast(clone, bio);
 
-        if (unlikely(bio_integrity(bio) != NULL)) {
+        if (bio_integrity(bio)) {
                 int r;
 
                 if (unlikely(!dm_target_has_integrity(tio->ti->type) &&
@@ -1336,11 +1336,7 @@ static int clone_bio(struct dm_target_io *tio, struct bio *bio,
                         return r;
         }
 
-        bio_advance(clone, to_bytes(sector - clone->bi_iter.bi_sector));
-        clone->bi_iter.bi_size = to_bytes(len);
-
-        if (unlikely(bio_integrity(bio) != NULL))
-                bio_integrity_trim(clone);
+        bio_trim(clone, sector - clone->bi_iter.bi_sector, len);
 
         return 0;
 }
@@ -1588,6 +1584,9 @@ static void init_clone_info(struct clone_info *ci, struct mapped_device *md,
         ci->sector = bio->bi_iter.bi_sector;
 }
 
+#define __dm_part_stat_sub(part, field, subnd)  \
+        (part_stat_get(part, field) -= (subnd))
+
 /*
  * Entry point to split a bio into clones and submit them to the targets.
  */
@@ -1642,7 +1641,21 @@ static blk_qc_t __split_and_process_bio(struct mapped_device *md,
                                 struct bio *b = bio_split(bio, bio_sectors(bio) - ci.sector_count,
                                                           GFP_NOIO, &md->queue->bio_split);
                                 ci.io->orig_bio = b;
+
+                                /*
+                                 * Adjust IO stats for each split, otherwise upon queue
+                                 * reentry there will be redundant IO accounting.
+                                 * NOTE: this is a stop-gap fix, a proper fix involves
+                                 * significant refactoring of DM core's bio splitting
+                                 * (by eliminating DM's splitting and just using bio_split)
+                                 */
+                                part_stat_lock();
+                                __dm_part_stat_sub(&dm_disk(md)->part0,
+                                                   sectors[op_stat_group(bio_op(bio))], ci.sector_count);
+                                part_stat_unlock();
+
                                 bio_chain(b, bio);
+                                trace_block_split(md->queue, b, bio->bi_iter.bi_sector);
                                 ret = generic_make_request(bio);
                                 break;
                         }
@@ -1713,6 +1726,15 @@ out:
         return ret;
 }
 
+static blk_qc_t dm_process_bio(struct mapped_device *md,
+                               struct dm_table *map, struct bio *bio)
+{
+        if (dm_get_md_type(md) == DM_TYPE_NVME_BIO_BASED)
+                return __process_bio(md, map, bio);
+        else
+                return __split_and_process_bio(md, map, bio);
+}
+
 static blk_qc_t dm_make_request(struct request_queue *q, struct bio *bio)
 {
         struct mapped_device *md = q->queuedata;
@@ -1733,10 +1755,7 @@ static blk_qc_t dm_make_request(struct request_queue *q, struct bio *bio)
                 return ret;
         }
 
-        if (dm_get_md_type(md) == DM_TYPE_NVME_BIO_BASED)
-                ret = __process_bio(md, map, bio);
-        else
-                ret = __split_and_process_bio(md, map, bio);
+        ret = dm_process_bio(md, map, bio);
 
         dm_put_live_table(md, srcu_idx);
         return ret;
@@ -2415,9 +2434,9 @@ static void dm_wq_work(struct work_struct *work)
                         break;
 
                 if (dm_request_based(md))
-                        generic_make_request(c);
+                        (void) generic_make_request(c);
                 else
-                        __split_and_process_bio(md, map, c);
+                        (void) dm_process_bio(md, map, c);
         }
 
         dm_put_live_table(md, srcu_idx);