Today's linux-next build (x86_64 allmodconfig) failed like this:
/drivers/char/tty_ioctl.c: In function 'change_termios':
drivers/isdn/capi/capi.c:1234: error: implicit declaration of function 'n_tty_ioctl'
drivers/isdn/gigaset/ser-gigaset.c: In function 'gigaset_tty_ioctl':
drivers/isdn/gigaset/ser-gigaset.c:648: error: implicit declaration of function 'n_tty_ioctl'
Introduced by commit 
686b5e4aea05a80e370dc931b7f4a8d03c80da54
("tty-move-canon-specials").  I added the following patch (which may not
be correct).
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
        int error = 0;
        switch (cmd) {
        default:
-               error = n_tty_ioctl (tty, file, cmd, arg);
+               error = n_tty_ioctl_helper(tty, file, cmd, arg);
                break;
        }
        return error;
 
        case TCGETS:
        case TCGETA:
                /* pass through to underlying serial device */
-               rc = n_tty_ioctl(tty, file, cmd, arg);
+               rc = n_tty_ioctl_helper(tty, file, cmd, arg);
                break;
 
        case TCFLSH:
                        break;
                }
                /* flush the serial port's buffer */
-               rc = n_tty_ioctl(tty, file, cmd, arg);
+               rc = n_tty_ioctl_helper(tty, file, cmd, arg);
                break;
 
        case FIONREAD: