From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753063AbcKHHvU (ORCPT ); Tue, 8 Nov 2016 02:51:20 -0500 Received: from mx2.suse.de ([195.135.220.15]:45305 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752079AbcKHHvR (ORCPT ); Tue, 8 Nov 2016 02:51:17 -0500 Subject: Re: [PATCH v2] xen/manage: correct return value check on xenbus_scanf() To: Jan Beulich , David Vrabel , Boris Ostrovsky References: <58219077020000780011CF59@suse.com> Cc: xen-devel , lkml From: Juergen Gross Message-ID: Date: Tue, 8 Nov 2016 08:51:11 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <58219077020000780011CF59@suse.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/11/16 08:44, Jan Beulich wrote: > A negative return value indicates an error; in fact the function at > present won't ever return zero. > > Signed-off-by: Jan Beulich Reviewed-by: Juergen Gross > --- > v2: For consistency with other code don't consider zero an error > (utilizing that xenbus_scanf() at present won't return zero). > Adjust commit message accordingly. > --- > drivers/xen/manage.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- 4.9-rc4/drivers/xen/manage.c > +++ 4.9-rc4-xen-manage-xenbus_scanf/drivers/xen/manage.c > @@ -277,7 +277,7 @@ static void sysrq_handler(struct xenbus_ > err = xenbus_transaction_start(&xbt); > if (err) > return; > - if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) { > + if (xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key) < 0) { > pr_err("Unable to read sysrq code in control/sysrq\n"); > xenbus_transaction_end(xbt, 1); > return; > >