[PATCH] read_mapping_page for address space

Add read_mapping_page() which is used for callers that pass
mapping->a_ops->readpage as the filler for read_cache_page.  This removes
some duplication from filesystem code.

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c
index ffb79c4..39fedaa 100644
--- a/fs/reiserfs/xattr.c
+++ b/fs/reiserfs/xattr.c
@@ -452,8 +452,7 @@
 	/* We can deadlock if we try to free dentries,
 	   and an unlink/rmdir has just occured - GFP_NOFS avoids this */
 	mapping_set_gfp_mask(mapping, GFP_NOFS);
-	page = read_cache_page(mapping, n,
-			       (filler_t *) mapping->a_ops->readpage, NULL);
+	page = read_mapping_page(mapping, n, NULL);
 	if (!IS_ERR(page)) {
 		wait_on_page_locked(page);
 		kmap(page);