From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754488Ab3H1Soh (ORCPT ); Wed, 28 Aug 2013 14:44:37 -0400 Received: from mail-pd0-f176.google.com ([209.85.192.176]:36840 "EHLO mail-pd0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753754Ab3H1Sog (ORCPT ); Wed, 28 Aug 2013 14:44:36 -0400 Date: Wed, 28 Aug 2013 11:44:33 -0700 From: Guenter Roeck To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, Grant Likely , Linus Walleij Subject: Re: Missing removal of sysfs attributes in gpiolib Message-ID: <20130828184433.GA8240@roeck-us.net> References: <20130828175717.GA7493@roeck-us.net> <20130828183139.GA14627@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130828183139.GA14627@kroah.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 28, 2013 at 11:31:39AM -0700, Greg Kroah-Hartman wrote: > On Wed, Aug 28, 2013 at 10:57:17AM -0700, Guenter Roeck wrote: > > Hi, > > > > I noticed that gpiolib does not explicitly remove the sysfs attributes it > > created when exporting a gpio pin when the pin is unexported, ie when the > > associated device is removed. > > > > Are those attributes auto-removed when device_unregister() is called ? > > Yes they are. > Does that mean that the explicit attribute removal that is implemented in many drivers can be dropped ? That might save a lot of code. > > Sorry if this is a dumb question - I have not noticed this anywhere else, > > and I don't seem to be able to find the code actually performing auto-removal > > of manually created attributes, so I wonder if this is a bug or intentional. > > Hm, I thought this was listed in the kobject.txt documentation file, but > I don't seem to find it there. > Would be great if this could be documented somewhere (unless it is and I didn't find it ;). I would volunteer to do it myself, but I have no idea what the conditions for auto-removal are nor how to phrase it, nor where to put it. > But, ideally you aren't creating individual attributes directly, you are > using attribute groups for the device, right? > gpiolib does currently create individual attributes as well as attribute groups after registering the device. I was in the process of converting it to use device_create_with_groups() when I noticed that there is no removal, so I wondered. I take it that attribute groups created with sysfs_create_group() are auto-removed as well, correct ? Thanks, Guenter