From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754450Ab3EXU1x (ORCPT ); Fri, 24 May 2013 16:27:53 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:58153 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751685Ab3EXU1w (ORCPT ); Fri, 24 May 2013 16:27:52 -0400 Date: Fri, 24 May 2013 13:27:51 -0700 From: Andrew Morton To: jg1.han@samsung.com Cc: linux-kernel@vger.kernel.org, tj@kernel.org Subject: Re: [PATCH 1/2] backlight: add devm_backlight_device_{register,unregister}() Message-Id: <20130524132751.8bbcf26cb02c78ad9a8b7d80@linux-foundation.org> In-Reply-To: <20226221.131531368682106551.JavaMail.weblogic@epml12> References: <20226221.131531368682106551.JavaMail.weblogic@epml12> X-Mailer: Sylpheed 3.2.0beta5 (GTK+ 2.24.10; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 16 May 2013 05:28:26 +0000 (GMT) Jingoo Han wrote: > These functions allow the driver core to automatically clean up any > allocation made by backlight drivers. Thus it simplifies the error > paths. > > ... > > --- a/drivers/video/backlight/backlight.c > +++ b/drivers/video/backlight/backlight.c > @@ -370,6 +370,81 @@ void backlight_device_unregister(struct backlight_device *bd) > } > EXPORT_SYMBOL(backlight_device_unregister); > > +static void devm_backlight_device_release(struct device *dev, void *res) > +{ > + struct backlight_device *backlight = *(struct backlight_device **)res; > + > + backlight_device_unregister(backlight); > +} > > ... > > +struct backlight_device *devm_backlight_device_register(struct device *dev, > + const char *name, struct device *parent, void *devdata, > + const struct backlight_ops *ops, > + const struct backlight_properties *props) > +{ > + struct backlight_device **ptr, *backlight; > + > + ptr = devres_alloc(devm_backlight_device_release, sizeof(*ptr), > + GFP_KERNEL); Well this is an awkward-looking thing. We allocate a silly little 4- or 8-byte object just to track the backlight_device* via the devres system. I assume this was done so that devres could be used as a wrapper around the existing code? Really it would be better if things like backlight_device_register() were themselves directly converted to use devm_foo(), yes?