1 files changed, 36 insertions, 20 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 88d60202b9db..8c82373f7ff3 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -17,6 +17,7 @@
 #include <linux/mempool.h>
 #include <linux/slab.h>
 #include <linux/idr.h>
+#include <linux/blktrace_api.h>
 
 static const char *_name = DM_NAME;
 
@@ -334,6 +335,8 @@ static void dec_pending(struct dm_io *io, int error)
                         /* nudge anyone waiting on suspend queue */
                         wake_up(&io->md->wait);
 
+                blk_add_trace_bio(io->md->queue, io->bio, BLK_TA_COMPLETE);
+
                 bio_endio(io->bio, io->bio->bi_size, io->error);
                 free_io(io->md, io);
         }
@@ -392,6 +395,7 @@ static void __map_bio(struct dm_target *ti, struct bio *clone,
                       struct target_io *tio)
 {
         int r;
+        sector_t sector;
 
         /*
          * Sanity checks.
@@ -407,10 +411,17 @@ static void __map_bio(struct dm_target *ti, struct bio *clone,
          * this io.
          */
         atomic_inc(&tio->io->io_count);
+        sector = clone->bi_sector;
         r = ti->type->map(ti, clone, &tio->info);
-        if (r > 0)
+        if (r > 0) {
                 /* the bio has been remapped so dispatch it */
+
+                blk_add_trace_remap(bdev_get_queue(clone->bi_bdev), clone, 
+                                    tio->io->bio->bi_bdev->bd_dev, sector, 
+                                    clone->bi_sector);
+
                 generic_make_request(clone);
+        }
 
         else if (r < 0) {
                 /* error the io and bail out */
@@ -533,30 +544,35 @@ static void __clone_and_map(struct clone_info *ci)
 
         } else {
                 /*
-                 * Create two copy bios to deal with io that has
-                 * been split across a target.
+                 * Handle a bvec that must be split between two or more targets.
                  */
                 struct bio_vec *bv = bio->bi_io_vec + ci->idx;
+                sector_t remaining = to_sector(bv->bv_len);
+                unsigned int offset = 0;
 
-                clone = split_bvec(bio, ci->sector, ci->idx,
-                                   bv->bv_offset, max);
-                __map_bio(ti, clone, tio);
+                do {
+                        if (offset) {
+                                ti = dm_table_find_target(ci->map, ci->sector);
+                                max = max_io_len(ci->md, ci->sector, ti);
 
-                ci->sector += max;
-                ci->sector_count -= max;
-                ti = dm_table_find_target(ci->map, ci->sector);
-
-                len = to_sector(bv->bv_len) - max;
-                clone = split_bvec(bio, ci->sector, ci->idx,
-                                   bv->bv_offset + to_bytes(max), len);
-                tio = alloc_tio(ci->md);
-                tio->io = ci->io;
-                tio->ti = ti;
-                memset(&tio->info, 0, sizeof(tio->info));
-                __map_bio(ti, clone, tio);
+                                tio = alloc_tio(ci->md);
+                                tio->io = ci->io;
+                                tio->ti = ti;
+                                memset(&tio->info, 0, sizeof(tio->info));
+                        }
+
+                        len = min(remaining, max);
+
+                        clone = split_bvec(bio, ci->sector, ci->idx,
+                                           bv->bv_offset + offset, len);
+
+                        __map_bio(ti, clone, tio);
+
+                        ci->sector += len;
+                        ci->sector_count -= len;
+                        offset += to_bytes(len);
+                } while (remaining -= len);
 
-                ci->sector += len;
-                ci->sector_count -= len;
                 ci->idx++;
         }
 }