In function bdi_set_min_ratio, min_ratio is unsigned int, it will
result underflow when setting min_ratio below bdi->min_ratio, it
is confusing. Rework it, no functional change.
Signed-off-by: Chen Wandun <[email protected]>
---
mm/page-writeback.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 438762173a59..d4291de77097 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -655,18 +655,25 @@ static unsigned int bdi_min_ratio;
int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio)
{
+ unsigned int delta;
int ret = 0;
spin_lock_bh(&bdi_lock);
if (min_ratio > bdi->max_ratio) {
ret = -EINVAL;
} else {
- min_ratio -= bdi->min_ratio;
- if (bdi_min_ratio + min_ratio < 100) {
- bdi_min_ratio += min_ratio;
- bdi->min_ratio += min_ratio;
+ if (min_ratio < bdi->min_ratio) {
+ delta = bdi->min_ratio - min_ratio;
+ bdi_min_ratio -= delta;
+ bdi->min_ratio = min_ratio;
} else {
- ret = -EINVAL;
+ delta = min_ratio - bdi->min_ratio;
+ if (bdi_min_ratio + delta < 100) {
+ bdi_min_ratio += delta;
+ bdi->min_ratio = min_ratio;
+ } else {
+ ret = -EINVAL;
+ }
}
}
spin_unlock_bh(&bdi_lock);
--
2.25.1