The quilt patch titled
Subject: mm: zswap: fix zswap_never_enabled() for CONFIG_ZSWAP==N
has been removed from the -mm tree. Its filename was
mm-zswap-fix-zswap_never_enabled-for-config_zswap==n.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Barry Song <v-songbaohua@xxxxxxxx>
Subject: mm: zswap: fix zswap_never_enabled() for CONFIG_ZSWAP==N
Date: Sun, 30 Jun 2024 11:22:31 +1200
If CONFIG_ZSWAP is set to N, it means zswap cannot be enabled.
zswap_never_enabled() should return true.
The only effect of this issue is that with Barry's latest large folio
swapin patches for zram ("mm: support mTHP swap-in for zRAM-like
swapfile"), we will always fallback to order-0 swapin, even mistakenly
when !CONFIG_ZSWAP.
Basically this bug makes Barry's in progress patches not work at all.
The API was created to inform the mm core that zswap has never been
enabled, allowing the mm core to perform mTHP swap-in. This is a
transitional solution until zswap supports mTHP. If zswap has been
enabled, performing mTHP swap-in will result in corrupted data. You
may find the answer in the mTHP swap-in series:
https://lore.kernel.org/linux-mm/CAJD7tkZ4FQr6HZpduOdvmqgg_-whuZYE-Bz5O2t6yzw6Yg+v1A@xxxxxxxxxxxxxx/
Link: https://lkml.kernel.org/r/20240629232231.42394-1-21cnbao@xxxxxxxxx
Fixes: 0300e17d67c3 ("mm: zswap: add zswap_never_enabled()")
Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx>
Reviewed-by: Chengming Zhou <chengming.zhou@xxxxxxxxx>
Acked-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Acked-by: Chris Li <chrisl@xxxxxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Nhat Pham <nphamcs@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/zswap.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/include/linux/zswap.h~mm-zswap-fix-zswap_never_enabled-for-config_zswap==n
+++ a/include/linux/zswap.h
@@ -68,7 +68,7 @@ static inline bool zswap_is_enabled(void
static inline bool zswap_never_enabled(void)
{
- return false;
+ return true;
}
#endif
_
Patches currently in -mm which might be from v-songbaohua@xxxxxxxx are
