[PATCH 7/7] dm: call dm_zone_endio after the target endio callback for zoned devices

Pankaj Raghav
2023-01-06T08:34:41Z

dm_zone_endio() updates the bi_sector of orig bio for zoned devices that
uses either native append or append emulation, and it is called before the
endio of the target. But target endio can still update the clone bio
after dm_zone_endio is called, thereby, the orig bio does not contain
the updated information anymore.

Currently, this is not a problem as the targets that support zoned devices
such as dm-zoned, dm-linear, and dm-crypt do not have an endio function,
and even if they do (such as dm-flakey), they don't modify the
bio->bi_iter.bi_sector of the cloned bio that is used to update the
orig_bio's bi_sector in dm_zone_endio function.

Call dm_zone_endio for zoned devices after calling the target's endio
function.

Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
---
drivers/md/dm.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index b424a6ee27ba..fdef74fe8bd1 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1109,10 +1109,6 @@ static void clone_endio(struct bio *bio)
disable_write_zeroes(md);
}

- if (static_branch_unlikely(&zoned_enabled) &&
- unlikely(bdev_is_zoned(bio->bi_bdev)))
- dm_zone_endio(io, bio);
-
if (endio) {
int r = endio(ti, bio, &error);
switch (r) {
@@ -1141,6 +1137,10 @@ static void clone_endio(struct bio *bio)
}
}

+ if (static_branch_unlikely(&zoned_enabled) &&
+ unlikely(bdev_is_zoned(bio->bi_bdev)))
+ dm_zone_endio(io, bio);
+
if (static_branch_unlikely(&swap_bios_enabled) &&
unlikely(swap_bios_limit(ti, bio)))
up(&md->swap_bios_semaphore);
--
2.25.1