From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755855Ab2DXQc2 (ORCPT ); Tue, 24 Apr 2012 12:32:28 -0400 Received: from h1446028.stratoserver.net ([85.214.92.142]:45343 "EHLO mail.ahsoftware.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755443Ab2DXQc0 (ORCPT ); Tue, 24 Apr 2012 12:32:26 -0400 Message-ID: <4F96D58A.3070008@ahsoftware.de> Date: Tue, 24 Apr 2012 18:32:10 +0200 From: Alexander Holler User-Agent: Mozilla/5.0 (X11; Linux i686; rv:10.0.1) Gecko/20120303 Thunderbird/10.0.1 MIME-Version: 1.0 To: shuahkhan@gmail.com CC: linux-kernel@vger.kernel.org, Richard Purdie , Andrew Morton Subject: Re: [PATCH v2] leds: heartbeat: stop on shutdown References: <1335275034-22135-1-git-send-email-holler@ahsoftware.de> <1335280022-16308-1-git-send-email-holler@ahsoftware.de> <1335281074.2347.4.camel@lorien2> In-Reply-To: <1335281074.2347.4.camel@lorien2> 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 Am 24.04.2012 17:24, schrieb Shuah Khan: > On Tue, 2012-04-24 at 17:07 +0200, Alexander Holler wrote: >> A halted kernel should not show a heartbeat. >> >> Signed-off-by: Alexander Holler >> --- >> drivers/leds/ledtrig-heartbeat.c | 18 +++++++++++++++++- >> 1 files changed, 17 insertions(+), 1 deletions(-) >> >> diff --git a/drivers/leds/ledtrig-heartbeat.c b/drivers/leds/ledtrig-heartbeat.c >> index 759c0bb..1c05bd9 100644 >> --- a/drivers/leds/ledtrig-heartbeat.c >> +++ b/drivers/leds/ledtrig-heartbeat.c >> @@ -18,6 +18,7 @@ >> #include >> #include >> #include >> +#include >> #include "leds.h" >> >> struct heartbeat_trig_data { >> @@ -101,13 +102,28 @@ static struct led_trigger heartbeat_led_trigger = { >> .deactivate = heartbeat_trig_deactivate, >> }; >> >> +static int heartbeat_reboot_notifier(struct notifier_block *nb, >> + unsigned long code, void *unused) >> +{ >> + led_trigger_unregister(&heartbeat_led_trigger); >> + return NOTIFY_DONE; >> +} >> + >> +static struct notifier_block heartbeat_reboot_nb = { >> + .notifier_call = heartbeat_reboot_notifier, >> +}; >> + >> static int __init heartbeat_trig_init(void) >> { >> - return led_trigger_register(&heartbeat_led_trigger); >> + int rc = led_trigger_register(&heartbeat_led_trigger); >> + if( ! rc ) >> + register_reboot_notifier(&heartbeat_reboot_nb); > > Do you need to check return value here? I see return value being checked > in some places in the kernel and not in others. Not checking is fine for > now since register_reboot_notifier() always returns 0. > > Maybe adding return handling might not be a bad idea to be consistent > with other places that do check. What to do if it fails? As long as unregister_reboot_notifier() doesn't do something bad with non-registered notifiers (which it doesn't), I would let the init still succeed. And to not unregister a non-registered-reboot_notifier, a long-living bool would be needed. > FYI - Andrew Morton is handling led patches these days. You might want > to send include him I have added him to CC, thanks. Regards, Alexander