[PATCH v2 3/5] staging: erofs: move shrink accounting inside the function

From: Gao Xiang
Date: Wed Jan 16 2019 - 08:11:50 EST


This patch moves the &erofs_global_shrink_cnt accounting
from the caller to erofs_workgroup_get(). It's cleaner and
it matches erofs_workgroup_put() better. No behavior change.

Reviewed-by: Chao Yu <yuchao0@xxxxxxxxxx>
Reviewed-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Gao Xiang <gaoxiang25@xxxxxxxxxx>
---
change log v2:
- fix commit message as Dan Carpenter pointed out to make more clear.

Thanks,
Gao Xiang

drivers/staging/erofs/utils.c | 17 +++++++----------
1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/drivers/staging/erofs/utils.c b/drivers/staging/erofs/utils.c
index d24945aab133..5695efaeb43a 100644
--- a/drivers/staging/erofs/utils.c
+++ b/drivers/staging/erofs/utils.c
@@ -34,29 +34,29 @@ static atomic_long_t erofs_global_shrink_cnt;
#define __erofs_workgroup_get(grp) atomic_inc(&(grp)->refcount)
#define __erofs_workgroup_put(grp) atomic_dec(&(grp)->refcount)

-static int erofs_workgroup_get(struct erofs_workgroup *grp, int *ocnt)
+static int erofs_workgroup_get(struct erofs_workgroup *grp)
{
int o;

repeat:
o = erofs_wait_on_workgroup_freezed(grp);
-
if (unlikely(o <= 0))
return -1;

if (unlikely(atomic_cmpxchg(&grp->refcount, o, o + 1) != o))
goto repeat;

- *ocnt = o;
+ /* decrease refcount paired by erofs_workgroup_put */
+ if (unlikely(o == 1))
+ atomic_long_dec(&erofs_global_shrink_cnt);
return 0;
}

-struct erofs_workgroup *erofs_find_workgroup(
- struct super_block *sb, pgoff_t index, bool *tag)
+struct erofs_workgroup *erofs_find_workgroup(struct super_block *sb,
+ pgoff_t index, bool *tag)
{
struct erofs_sb_info *sbi = EROFS_SB(sb);
struct erofs_workgroup *grp;
- int oldcount;

repeat:
rcu_read_lock();
@@ -65,15 +65,12 @@ struct erofs_workgroup *erofs_find_workgroup(
*tag = xa_pointer_tag(grp);
grp = xa_untag_pointer(grp);

- if (erofs_workgroup_get(grp, &oldcount)) {
+ if (erofs_workgroup_get(grp)) {
/* prefer to relax rcu read side */
rcu_read_unlock();
goto repeat;
}

- /* decrease refcount added by erofs_workgroup_put */
- if (unlikely(oldcount == 1))
- atomic_long_dec(&erofs_global_shrink_cnt);
DBG_BUGON(index != grp->index);
}
rcu_read_unlock();
--
2.14.4