new helper: file_inode(file)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/mm/swapfile.c b/mm/swapfile.c
index e97a0e5..ed39300 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1699,7 +1699,7 @@
 	len = seq_path(swap, &file->f_path, " \t\n\\");
 	seq_printf(swap, "%*s%s\t%u\t%u\t%d\n",
 			len < 40 ? 40 - len : 1, " ",
-			S_ISBLK(file->f_path.dentry->d_inode->i_mode) ?
+			S_ISBLK(file_inode(file)->i_mode) ?
 				"partition" : "file\t",
 			si->pages << (PAGE_SHIFT - 10),
 			si->inuse_pages << (PAGE_SHIFT - 10),