[PATCH v14 11/13] dm: call dm_zone_endio after the target endio callback for zoned devices

Pankaj Raghav
2022-09-20T09:22:08Z

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.

This is a prep patch for the new dm-po2zoned target as it modifies
bi_sector in the endio callback.

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

Reviewed-by: Mike Snitzer <snitzer@kernel.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 7c35dea88ed1..874e1dc9fc26 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1122,10 +1122,6 @@ 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) {
@@ -1154,6 +1150,10 @@ 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