From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751135AbdEaTuR (ORCPT ); Wed, 31 May 2017 15:50:17 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:36016 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750952AbdEaTuQ (ORCPT ); Wed, 31 May 2017 15:50:16 -0400 Date: Wed, 31 May 2017 20:50:12 +0100 From: Okash Khawaja To: Greg Kroah-Hartman , Jiri Slaby , Samuel Thibault , linux-kernel@vger.kernel.org Cc: William Hubbs , Chris Brannon , Kirk Reiser , speakup@linux-speakup.org, devel@driverdev.osuosl.org Subject: [patch] staging: speakup: check for null before calling TTY's flush_buffer Message-ID: <20170531195012.GA967@sanghar> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.8.2 (2017-04-18) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We should check the flush_buffer method of a tty for null before invoking it. Some drivers such as usbserial don't implement flush_buffer. This will be required for upcoming patches where we expand spk_ttyio to support more than just ttyS*. Signed-off-by: Okash Khawaja Reviewed-by: Samuel Thibault --- drivers/staging/speakup/spk_ttyio.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/staging/speakup/spk_ttyio.c +++ b/drivers/staging/speakup/spk_ttyio.c @@ -227,7 +227,8 @@ static unsigned char spk_ttyio_in_nowait static void spk_ttyio_flush_buffer(void) { - speakup_tty->ops->flush_buffer(speakup_tty); + if (speakup_tty->ops->flush_buffer) + speakup_tty->ops->flush_buffer(speakup_tty); } int spk_ttyio_synth_probe(struct spk_synth *synth)