From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-wm0-f44.google.com ([74.125.82.44]:33987 "EHLO mail-wm0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965098AbcCPVdK (ORCPT ); Wed, 16 Mar 2016 17:33:10 -0400 Received: by mail-wm0-f44.google.com with SMTP id p65so361798wmp.1 for ; Wed, 16 Mar 2016 14:33:09 -0700 (PDT) Subject: Re: [PATCH] media: rc: remove unneeded mutex in rc_register_device To: Vladimir Zapolskiy , Mauro Carvalho Chehab References: <56E9ABB0.3010106@gmail.com> <56E9B4FA.3060707@mentor.com> Cc: linux-media@vger.kernel.org From: Heiner Kallweit Message-ID: <56E9CEFB.1050601@gmail.com> Date: Wed, 16 Mar 2016 22:24:11 +0100 MIME-Version: 1.0 In-Reply-To: <56E9B4FA.3060707@mentor.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Am 16.03.2016 um 20:33 schrieb Vladimir Zapolskiy: > On 16.03.2016 20:53, Heiner Kallweit wrote: >> Access to dev->initialized is atomic, therefore we don't have to >> protect it with a mutex. > > Mutexes are used to split the code to mutually exclusive execution blocks, > so not arguing about the apparently correct change itself I want to > emphasize that the given explanation of the change in the commit message is > wrong. Atomic access does not cancel a specific care about execution > ordering. > > Indirectly it applies to ("rc-core: allow calling rc_open with device not > initialized"), where "initialized" bool property was changed to atomic_t > type --- this (sub-)change is just useless. > > Please grasp the topic and reword the commit message. > Thanks for the hint, you're right. Will change the commit message and send a v2. Regards, Heiner >> Signed-off-by: Heiner Kallweit >> --- >> drivers/media/rc/rc-main.c | 2 -- >> 1 file changed, 2 deletions(-) >> >> diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c >> index 4e9bbe7..68541b1 100644 >> --- a/drivers/media/rc/rc-main.c >> +++ b/drivers/media/rc/rc-main.c >> @@ -1492,9 +1492,7 @@ int rc_register_device(struct rc_dev *dev) >> } >> >> /* Allow the RC sysfs nodes to be accessible */ >> - mutex_lock(&dev->lock); >> atomic_set(&dev->initialized, 1); >> - mutex_unlock(&dev->lock); >> >> IR_dprintk(1, "Registered rc%u (driver: %s, remote: %s, mode %s)\n", >> dev->minor, >> > > -- > With best wishes, > Vladimir >