From: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
We have to invalidate any duplicate entry even when !zswap_enabled
since zswap can be disabled anytime. If the folio store success before,
then got dirtied again but zswap disabled, we won't invalidate the old
duplicate entry in the zswap_store(). So later lru writeback may
overwrite the new data in swapfile.
Fixes: 42c06a0e8ebe ("mm: kill frontswap")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
---
mm/zswap.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/mm/zswap.c b/mm/zswap.c
index fe7ee2640c69..32633d0597dc 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -1516,7 +1516,7 @@ bool zswap_store(struct folio *folio)
if (folio_test_large(folio))
return false;
- if (!zswap_enabled || !tree)
+ if (!tree)
return false;
/*
@@ -1531,6 +1531,10 @@ bool zswap_store(struct folio *folio)
zswap_invalidate_entry(tree, dupentry);
}
spin_unlock(&tree->lock);
+
+ if (!zswap_enabled)
+ return false;
+
objcg = get_obj_cgroup_from_folio(folio);
if (objcg && !obj_cgroup_may_zswap(objcg)) {
memcg = get_mem_cgroup_from_objcg(objcg);
--
2.40.1
