mm/damon/paddr: fix missing folio_put()

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>

diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index e1a4315..402d30b 100644 (file)
--- 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();