filemap: Use folio_put_refs() in filemap_free_folio()

This shrinks filemap_free_folio() by 55 bytes in my .config; 24 bytes
from removing the VM_BUG_ON_FOLIO() and 31 bytes from unifying the
small/large folio paths.

We could just use folio_ref_sub() here since the caller should hold a
reference (as the VM_BUG_ON_FOLIO() was asserting), but that's fragile.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

diff --git a/mm/filemap.c b/mm/filemap.c
index 2fd9b2f24025ff69b2f272cfc5aaff8e74d4c9df..afc8f5ca85ac2c7e436eabd0edb581b6a2a707a0 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -231,17 +231,15 @@ void __filemap_remove_folio(struct folio *folio, void *shadow)
 void filemap_free_folio(struct address_space *mapping, struct folio *folio)
 {
        void (*freepage)(struct page *);
+       int refs = 1;
 
        freepage = mapping->a_ops->freepage;
        if (freepage)
                freepage(&folio->page);
 
-       if (folio_test_large(folio) && !folio_test_hugetlb(folio)) {
-               folio_ref_sub(folio, folio_nr_pages(folio));
-               VM_BUG_ON_FOLIO(folio_ref_count(folio) <= 0, folio);
-       } else {
-               folio_put(folio);
-       }
+       if (folio_test_large(folio) && !folio_test_hugetlb(folio))
+               refs = folio_nr_pages(folio);
+       folio_put_refs(folio, refs);
 }
 
 /**