ubifs: Convert ubifs_writepage to use a folio

We still pass the page down to do_writepage(), but ubifs_writepage()
itself is now large folio safe.  It also contains far fewer hidden calls
to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 2022a31..a4e8bec 100644 (file)
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1004,21 +1004,18 @@ static int do_writepage(struct page *page, int len)
 static int ubifs_writepage(struct folio *folio, struct writeback_control *wbc,
                void *data)
 {
-       struct page *page = &folio->page;
-       struct inode *inode = page->mapping->host;
+       struct inode *inode = folio->mapping->host;
        struct ubifs_info *c = inode->i_sb->s_fs_info;
        struct ubifs_inode *ui = ubifs_inode(inode);
        loff_t i_size =  i_size_read(inode), synced_i_size;
-       pgoff_t end_index = i_size >> PAGE_SHIFT;
-       int err, len = i_size & (PAGE_SIZE - 1);
-       void *kaddr;
+       int err, len = folio_size(folio);
 
        dbg_gen("ino %lu, pg %lu, pg flags %#lx",
-               inode->i_ino, page->index, page->flags);
-       ubifs_assert(c, PagePrivate(page));
+               inode->i_ino, folio->index, folio->flags);
+       ubifs_assert(c, folio->private != NULL);
 
-       /* Is the page fully outside @i_size? (truncate in progress) */
-       if (page->index > end_index || (page->index == end_index && !len)) {
+       /* Is the folio fully outside @i_size? (truncate in progress) */
+       if (folio_pos(folio) >= i_size) {
                err = 0;
                goto out_unlock;
        }
@@ -1027,9 +1024,9 @@ static int ubifs_writepage(struct folio *folio, struct writeback_control *wbc,
        synced_i_size = ui->synced_i_size;
        spin_unlock(&ui->ui_lock);
 
-       /* Is the page fully inside @i_size? */
-       if (page->index < end_index) {
-               if (page->index >= synced_i_size >> PAGE_SHIFT) {
+       /* Is the folio fully inside i_size? */
+       if (folio_pos(folio) + len <= i_size) {
+               if (folio_pos(folio) >= synced_i_size) {
                        err = inode->i_sb->s_op->write_inode(inode, NULL);
                        if (err)
                                goto out_redirty;
@@ -1042,20 +1039,18 @@ static int ubifs_writepage(struct folio *folio, struct writeback_control *wbc,
                         * with this.
                         */
                }
-               return do_writepage(page, PAGE_SIZE);
+               return do_writepage(&folio->page, len);
        }
 
        /*
-        * The page straddles @i_size. It must be zeroed out on each and every
+        * The folio straddles @i_size. It must be zeroed out on each and every
         * writepage invocation because it may be mmapped. "A file is mapped
         * in multiples of the page size. For a file that is not a multiple of
         * the page size, the remaining memory is zeroed when mapped, and
         * writes to that region are not written out to the file."
         */
-       kaddr = kmap_atomic(page);
-       memset(kaddr + len, 0, PAGE_SIZE - len);
-       flush_dcache_page(page);
-       kunmap_atomic(kaddr);
+       len = i_size - folio_pos(folio);
+       folio_zero_segment(folio, len, folio_size(folio));
 
        if (i_size > synced_i_size) {
                err = inode->i_sb->s_op->write_inode(inode, NULL);
@@ -1063,16 +1058,16 @@ static int ubifs_writepage(struct folio *folio, struct writeback_control *wbc,
                        goto out_redirty;
        }
 
-       return do_writepage(page, len);
+       return do_writepage(&folio->page, len);
 out_redirty:
        /*
-        * redirty_page_for_writepage() won't call ubifs_dirty_inode() because
+        * folio_redirty_for_writepage() won't call ubifs_dirty_inode() because
         * it passes I_DIRTY_PAGES flag while calling __mark_inode_dirty(), so
         * there is no need to do space budget for dirty inode.
         */
-       redirty_page_for_writepage(wbc, page);
+       folio_redirty_for_writepage(wbc, folio);
 out_unlock:
-       unlock_page(page);
+       folio_unlock(folio);
        return err;
 }