shmem: convert shmem_delete_from_page_cache() to take a folio

Remove the assertion that the page is not Compound as this function now
handles large folios correctly.

Link: https://lkml.kernel.org/r/20220902194653.1739778-8-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/shmem.c b/mm/shmem.c
index 3d2d35728793b94438587eec1b224d459066b191..9e851fc876016aa2058a17ec65386e87881d1bf4 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -763,23 +763,22 @@ error:
 }
 
 /*
- * Like delete_from_page_cache, but substitutes swap for page.
+ * Like delete_from_page_cache, but substitutes swap for @folio.
  */
-static void shmem_delete_from_page_cache(struct page *page, void *radswap)
+static void shmem_delete_from_page_cache(struct folio *folio, void *radswap)
 {
-       struct address_space *mapping = page->mapping;
+       struct address_space *mapping = folio->mapping;
+       long nr = folio_nr_pages(folio);
        int error;
 
-       VM_BUG_ON_PAGE(PageCompound(page), page);
-
        xa_lock_irq(&mapping->i_pages);
-       error = shmem_replace_entry(mapping, page->index, page, radswap);
-       page->mapping = NULL;
-       mapping->nrpages--;
-       __dec_lruvec_page_state(page, NR_FILE_PAGES);
-       __dec_lruvec_page_state(page, NR_SHMEM);
+       error = shmem_replace_entry(mapping, folio->index, folio, radswap);
+       folio->mapping = NULL;
+       mapping->nrpages -= nr;
+       __lruvec_stat_mod_folio(folio, NR_FILE_PAGES, -nr);
+       __lruvec_stat_mod_folio(folio, NR_SHMEM, -nr);
        xa_unlock_irq(&mapping->i_pages);
-       put_page(page);
+       folio_put(folio);
        BUG_ON(error);
 }
 
@@ -1416,7 +1415,7 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
                spin_unlock_irq(&info->lock);
 
                swap_shmem_alloc(swap);
-               shmem_delete_from_page_cache(&folio->page, swp_to_radix_entry(swap));
+               shmem_delete_from_page_cache(folio, swp_to_radix_entry(swap));
 
                mutex_unlock(&shmem_swaplist_mutex);
                BUG_ON(folio_mapped(folio));