new helper: file_inode(file)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/drivers/isdn/i4l/isdn_ppp.c b/drivers/isdn/i4l/isdn_ppp.c
index 61d78fa..38ceac5 100644
--- a/drivers/isdn/i4l/isdn_ppp.c
+++ b/drivers/isdn/i4l/isdn_ppp.c
@@ -668,7 +668,7 @@
 
 	if (is->debug & 0x2)
 		printk(KERN_DEBUG "isdn_ppp_poll: minor: %d\n",
-		       iminor(file->f_path.dentry->d_inode));
+		       iminor(file_inode(file)));
 
 	/* just registers wait_queue hook. This doesn't really wait. */
 	poll_wait(file, &is->wq, wait);