[merged mm-stable] mm-shmem-only-remove-inode-from-swaplist-when-its-swapped-page-count-is-0.patch removed from -mm tree

[merged mm-stable] mm-shmem-only-remove-inode-from-swaplist-when-its-swapped-page-count-is-0.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm: shmem: only remove inode from swaplist when it's swapped page count is 0
has been removed from the -mm tree.  Its filename was
     mm-shmem-only-remove-inode-from-swaplist-when-its-swapped-page-count-is-0.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: Kemeng Shi <shikemeng@huaweicloud.com>
Subject: mm: shmem: only remove inode from swaplist when it's swapped page count is 0
Date: Sat, 17 May 2025 01:09:38 +0800

Even if we fail to allocate a swap entry, the inode might have previously
allocated entry and we might take inode containing swap entry off
swaplist.  As a result, try_to_unuse() may enter a potential dead loop to
repeatedly look for inode and clean it's swap entry.  Only take inode off
swaplist when it's swapped page count is 0 to fix the issue.

Link: https://lkml.kernel.org/r/20250516170939.965736-5-shikemeng@huaweicloud.com
Fixes: b487a2da3575 ("mm, swap: simplify folio swap allocation")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Kairui Song <kasong@tencent.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202505161438.9009cf47-lkp@intel.com
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/shmem.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/mm/shmem.c~mm-shmem-only-remove-inode-from-swaplist-when-its-swapped-page-count-is-0
+++ a/mm/shmem.c
@@ -1651,8 +1651,8 @@ try_split:
 		BUG_ON(folio_mapped(folio));
 		return swap_writepage(&folio->page, wbc);
 	}
-
-	list_del_init(&info->swaplist);
+	if (!info->swapped)
+		list_del_init(&info->swaplist);
 	mutex_unlock(&shmem_swaplist_mutex);
 	if (nr_pages > 1)
 		goto try_split;
_

Patches currently in -mm which might be from shikemeng@huaweicloud.com are

mm-swap-move-nr_swap_pages-counter-decrement-from-folio_alloc_swap-to-swap_range_alloc.patch
mm-swap-correctly-use-maxpages-in-swapon-syscall-to-avoid-potensial-deadloop.patch
mm-swap-fix-potensial-buffer-overflow-in-setup_clusters.patch
mm-swap-remove-stale-comment-stale-comment-in-cluster_alloc_swap_entry.patch