mm: shmem: drop folio reference count using 'nr_pages' in shmem_delete_from_page_cache()

To support large folio swapin/swapout for shmem in the following patches,
drop the folio's reference count by the number of pages contained in the
folio when a shmem folio is deleted from shmem pagecache after adding into
swap cache.

Link: https://lkml.kernel.org/r/b371eadb27f42fc51261c51008fbb9a334985b4c.1723434324.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/shmem.c b/mm/shmem.c
index e63393ced001819fe858be01dd126d31efe4acb9..598d003b7a894c3f7a11b3c0335bb85c3f602711 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -851,7 +851,7 @@ static void shmem_delete_from_page_cache(struct folio *folio, void *radswap)
        __lruvec_stat_mod_folio(folio, NR_FILE_PAGES, -nr);
        __lruvec_stat_mod_folio(folio, NR_SHMEM, -nr);
        xa_unlock_irq(&mapping->i_pages);
-       folio_put(folio);
+       folio_put_refs(folio, nr);
        BUG_ON(error);
 }