blktrace: support per-partition tracing

Though one can specify '-d /dev/sda1' when using blktrace, it still
traces the whole sda.

To support per-partition tracing, when we start tracing, we initialize
bt->start_lba and bt->end_lba to the start and end sector of that
partition.

Note some actions are per device, thus we don't filter 0-sector events.

The original patch and discussion can be found here:
	http://marc.info/?l=linux-btrace&m=122949374214540&w=2

Signed-off-by: Shawn Du <duyuyang@gmail.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
LKML-Reference: <49E42620.4050701@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 1 insertions, 1 deletions

diff --git a/block/compat_ioctl.c b/block/compat_ioctl.c
index f87615dea46b..f8c218cd08e1 100644
--- a/block/compat_ioctl.c
+++ b/block/compat_ioctl.c
@@ -568,7 +568,7 @@ static int compat_blk_trace_setup(struct block_device *bdev, char __user *arg)
         memcpy(&buts.name, &cbuts.name, 32);
 
         mutex_lock(&bdev->bd_mutex);
-        ret = do_blk_trace_setup(q, b, bdev->bd_dev, &buts);
+        ret = do_blk_trace_setup(q, b, bdev->bd_dev, bdev, &buts);
         mutex_unlock(&bdev->bd_mutex);
         if (ret)
                 return ret;