[PATCH] device-mapper disk statistics: timing

Record I/O timing statistics

The start time is added to struct dm_io, an existing structure allocated
privately internally within dm and attached to each incoming bio.

We export disk_round_stats() from block/ll_rw_blk.c instead of creating a
private clone.

Signed-off-by: Jun'ichi "Nick" Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index d38b4afa37ef..f9fc07efd2da 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -2579,6 +2579,8 @@ void disk_round_stats(struct gendisk *disk)
         disk->stamp = now;
 }
 
+EXPORT_SYMBOL_GPL(disk_round_stats);
+
 /*
  * queue lock must be held
  */