Use pgoff_t instead of unsigned long

Convert variables containing page indexes to pgoff_t.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index 0420a02..5e598c4 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -56,7 +56,8 @@
 		    read_actor_t actor)
 {
 	struct inode *inode = mapping->host;
-	unsigned long index, end_index, offset;
+	pgoff_t index, end_index;
+	unsigned long offset;
 	loff_t isize;
 
 	BUG_ON(!mapping->a_ops->get_xip_page);