[PATCH 6/8] dm: don't grab target io reference in dm_zone_map_bio

Ming Lei
2022-04-12T10:10:07Z

dm_zone_map_bio() is only called from __map_bio in which the io's
reference is grabbed already, and the reference won't be released
until the bio is submitted, so no necessary to do it dm_zone_map_bio
any more.

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
drivers/md/dm-core.h | 7 -------
drivers/md/dm-zone.c | 10 ----------
drivers/md/dm.c | 7 ++++++-
3 files changed, 6 insertions(+), 18 deletions(-)

diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h
index aefb080c230d..811c0ccbc63d 100644
--- a/drivers/md/dm-core.h
+++ b/drivers/md/dm-core.h
@@ -283,13 +283,6 @@ static inline void dm_io_set_flag(struct dm_io *io, unsigned int bit)
io->flags |= (1U << bit);
}

-static inline void dm_io_inc_pending(struct dm_io *io)
-{
- atomic_inc(&io->io_count);
-}
-
-void dm_io_dec_pending(struct dm_io *io, blk_status_t error);
-
static inline struct completion *dm_get_completion_from_kobject(struct kobject *kobj)
{
return &container_of(kobj, struct dm_kobject_holder, kobj)->completion;
diff --git a/drivers/md/dm-zone.c b/drivers/md/dm-zone.c
index c1ca9be4b79e..85d3c158719f 100644
--- a/drivers/md/dm-zone.c
+++ b/drivers/md/dm-zone.c
@@ -545,13 +545,6 @@ int dm_zone_map_bio(struct dm_target_io *tio)
return DM_MAPIO_KILL;
}

- /*
- * The target map function may issue and complete the IO quickly.
- * Take an extra reference on the IO to make sure it does disappear
- * until we run dm_zone_map_bio_end().
- */
- dm_io_inc_pending(io);
-
/* Let the target do its work */
r = ti->type->map(ti, clone);
switch (r) {
@@ -580,9 +573,6 @@ int dm_zone_map_bio(struct dm_target_io *tio)
break;
}

- /* Drop the extra reference on the IO */
- dm_io_dec_pending(io, sts);
-
if (sts != BLK_STS_OK)
return DM_MAPIO_KILL;

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index df1d013fb793..3c3ba6b4e19b 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -937,11 +937,16 @@ static inline bool dm_tio_is_normal(struct dm_target_io *tio)
!dm_tio_flagged(tio, DM_TIO_IS_DUPLICATE_BIO));
}

+static void dm_io_inc_pending(struct dm_io *io)
+{
+ atomic_inc(&io->io_count);
+}
+
/*
* Decrements the number of outstanding ios that a bio has been
* cloned into, completing the original io if necc.
*/
-void dm_io_dec_pending(struct dm_io *io, blk_status_t error)
+static void dm_io_dec_pending(struct dm_io *io, blk_status_t error)
{
/* Push-back supersedes any I/O errors */
if (unlikely(error)) {
--
2.31.1