dm: record old_sector in dm_target_io before calling map function

Prep for being able to defer trace_block_bio_remap() until when the
bio is remapped and submitted by the DM target.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h
index 253b6bb..e2128d1 100644 (file)
--- a/drivers/md/dm-core.h
+++ b/drivers/md/dm-core.h
@@ -216,6 +216,7 @@ struct dm_target_io {
        unsigned int target_bio_nr;
        unsigned int *len_ptr;
        bool inside_dm_io;
+       sector_t old_sector;
        struct bio clone;
 };
 

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 280c17a..08689b3 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -584,6 +584,7 @@ static struct bio *alloc_tio(struct clone_info *ci, struct dm_target *ti,
        tio->ti = ti;
        tio->target_bio_nr = target_bio_nr;
        tio->len_ptr = len;
+       tio->old_sector = 0;
 
        return &tio->clone;
 }
@@ -1139,7 +1140,6 @@ static void __map_bio(struct bio *clone)
 {
        struct dm_target_io *tio = clone_to_tio(clone);
        int r;
-       sector_t sector;
        struct dm_io *io = tio->io;
        struct dm_target *ti = tio->ti;
 
@@ -1151,7 +1151,7 @@ static void __map_bio(struct bio *clone)
         * this io.
         */
        dm_io_inc_pending(io);
-       sector = clone->bi_iter.bi_sector;
+       tio->old_sector = clone->bi_iter.bi_sector;
 
        if (unlikely(swap_bios_limit(ti, clone))) {
                struct mapped_device *md = io->md;
@@ -1176,7 +1176,8 @@ static void __map_bio(struct bio *clone)
                break;
        case DM_MAPIO_REMAPPED:
                /* the bio has been remapped so dispatch it */
-               trace_block_bio_remap(clone, bio_dev(io->orig_bio), sector);
+               trace_block_bio_remap(clone, bio_dev(io->orig_bio),
+                                     tio->old_sector);
                submit_bio_noacct(clone);
                break;
        case DM_MAPIO_KILL: