readahead: Use a folio in read_pages()

Handle multi-page folios correctly and removes a few calls to
compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/mm/readahead.c b/mm/readahead.c
index 4a60cdb64262af49fbc086c6fef0f33947786b8b..60a28af25c4ee1c18aa9fe4f0b907c8b03e41078 100644 (file)
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -145,7 +145,7 @@ EXPORT_SYMBOL_GPL(file_ra_state_init);
 static void read_pages(struct readahead_control *rac)
 {
        const struct address_space_operations *aops = rac->mapping->a_ops;
-       struct page *page;
+       struct folio *folio;
        struct blk_plug plug;
 
        if (!readahead_count(rac))
@@ -156,24 +156,23 @@ static void read_pages(struct readahead_control *rac)
        if (aops->readahead) {
                aops->readahead(rac);
                /*
-                * Clean up the remaining pages.  The sizes in ->ra
+                * Clean up the remaining folios.  The sizes in ->ra
                 * may be used to size the next readahead, so make sure
                 * they accurately reflect what happened.
                 */
-               while ((page = readahead_page(rac))) {
-                       rac->ra->size -= 1;
-                       if (rac->ra->async_size > 0) {
-                               rac->ra->async_size -= 1;
-                               delete_from_page_cache(page);
+               while ((folio = readahead_folio(rac)) != NULL) {
+                       unsigned long nr = folio_nr_pages(folio);
+
+                       rac->ra->size -= nr;
+                       if (rac->ra->async_size >= nr) {
+                               rac->ra->async_size -= nr;
+                               filemap_remove_folio(folio);
                        }
-                       unlock_page(page);
-                       put_page(page);
+                       folio_unlock(folio);
                }
        } else {
-               while ((page = readahead_page(rac))) {
-                       aops->readpage(rac->file, page);
-                       put_page(page);
-               }
+               while ((folio = readahead_folio(rac)))
+                       aops->readpage(rac->file, &folio->page);
        }
 
        blk_finish_plug(&plug);