From: "andrew.yang" <andrew.yang@mediatek.com>
Date: Wed, 22 Feb 2023 14:42:20 +0800
Subject: [PATCH] mm/damon/paddr: fix missing folio_put()
References: bsc#1012628
Patch-mainline: 6.2.3
Git-commit: 3f98c9a62c338bbe06a215c9491e6166ea39bf82

commit 3f98c9a62c338bbe06a215c9491e6166ea39bf82 upstream.

damon_get_folio() would always increase folio _refcount and
folio_isolate_lru() would increase folio _refcount if the folio's lru flag
is set.

If an unevictable folio isolated successfully, there will be two more
_refcount.  The one from folio_isolate_lru() will be decreased in
folio_puback_lru(), but the other one from damon_get_folio() will be left
behind.  This causes a pin page.

Whatever the case, the _refcount from damon_get_folio() should be
decreased.

Link: https://lkml.kernel.org/r/20230222064223.6735-1-andrew.yang@mediatek.com
Fixes: 57223ac29584 ("mm/damon/paddr: support the pageout scheme")
Signed-off-by: andrew.yang <andrew.yang@mediatek.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>	[5.16.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 mm/damon/paddr.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index e1a4315c..402d30b3 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -219,12 +219,11 @@ static unsigned long damon_pa_pageout(struct damon_region *r)
 			put_page(page);
 			continue;
 		}
-		if (PageUnevictable(page)) {
+		if (PageUnevictable(page))
 			putback_lru_page(page);
-		} else {
+		else
 			list_add(&page->lru, &page_list);
-			put_page(page);
-		}
+		put_page(page);
 	}
 	applied = reclaim_pages(&page_list);
 	cond_resched();
-- 
2.35.3