From: Tang Junhui <tang.junhui@xxxxxxxxxx>
In bch_mca_scan(), There are some confusion and logical error in the use of
loop variables. In this patch, we clarify them as:
1) nr: the number of btree nodes needs to scan, which will decrease after
we scan a btree node, and should not be less than 0;
2) i: the number of btree nodes have scanned, includes both
btree_cache_freeable and btree_cache, which should not be bigger than
btree_cache_used;
3) freed: the number of btree nodes have freed.
Signed-off-by: Tang Junhui <tang.junhui@xxxxxxxxxx>
Reviewed-by: Michael Lyle <mlyle@xxxxxxxx>
---
drivers/md/bcache/btree.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index b2d4899f48d5..d64aff0b8abc 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -665,6 +665,7 @@ static unsigned long bch_mca_scan(struct shrinker *shrink,
struct btree *b, *t;
unsigned long i, nr = sc->nr_to_scan;
unsigned long freed = 0;
+ unsigned int btree_cache_used;
if (c->shrinker_disabled)
return SHRINK_STOP;
@@ -689,9 +690,10 @@ static unsigned long bch_mca_scan(struct shrinker *shrink,
nr = min_t(unsigned long, nr, mca_can_free(c));
i = 0;
+ btree_cache_used = c->btree_cache_used;
list_for_each_entry_safe(b, t, &c->btree_cache_freeable, list) {
- if (freed >= nr)
- break;
+ if (nr <= 0)
+ goto out;
if (++i > 3 &&
!mca_reap(b, 0, false)) {
@@ -699,9 +701,10 @@ static unsigned long bch_mca_scan(struct shrinker *shrink,
rw_unlock(true, b);
freed++;
}
+ nr--;
}
- for (i = 0; (nr--) && i < c->btree_cache_used; i++) {
+ for (; (nr--) && i < btree_cache_used; i++) {
if (list_empty(&c->btree_cache))
goto out;
--
2.14.1
