From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754003AbZKDACI (ORCPT ); Tue, 3 Nov 2009 19:02:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753819AbZKDACH (ORCPT ); Tue, 3 Nov 2009 19:02:07 -0500 Received: from kroah.org ([198.145.64.141]:40406 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752473AbZKDACG (ORCPT ); Tue, 3 Nov 2009 19:02:06 -0500 Date: Tue, 3 Nov 2009 16:02:00 -0800 From: Greg KH To: Andrew Morton Cc: Sergei Shtylyov , linux-kernel@vger.kernel.org, david-b@pacbell.net, Kay Sievers , Tejun Heo Subject: Re: [PATCH] gpiolib: fix device_create() result check Message-ID: <20091104000200.GA29503@kroah.com> References: <200910202035.23981.sshtylyov@ru.mvista.com> <20091103144401.6fa4e130.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091103144401.6fa4e130.akpm@linux-foundation.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 03, 2009 at 02:44:01PM -0800, Andrew Morton wrote: > On Tue, 20 Oct 2009 20:35:23 +0400 > Sergei Shtylyov wrote: > > > In case of failure, device_create() returns not NULL but the error code. > > The current code checks for non-NULL though which causes kernel oops in > > sysfs_create_group() when device_create() fails. Check for error using > > IS_ERR() and propagate the error value using PTR_ERR() instead of fixed > > -ENODEV code returned now... > > Does anyone notice any missing information here? > > /** > * device_create - creates a device and registers it with sysfs > * @class: pointer to the struct class that this device should be registered to > * @parent: pointer to the parent struct device of this new device, if any > * @devt: the dev_t for the char device to be added > * @drvdata: the data to be added to the device for callbacks > * @fmt: string for the device's name > * > * This function can be used by char device classes. A struct device > * will be created in sysfs, registered to the specified class. > * > * A "dev" file will be created, showing the dev_t for the device, if > * the dev_t is not 0,0. > * If a pointer to a parent struct device is passed in, the newly created > * struct device will be a child of that device in sysfs. > * The pointer to the struct device will be returned from the call. > * Any further sysfs files that might be required can be created using this > * pointer. > * > * Note: the struct class passed to this function must have previously > * been created with a call to class_create(). > */ > > > Why do we do this to ourselves? Because we suck at writing documentation? :) Patches to add the one line: "If an error happens, a PTR_ERR is returned instead of a pointer to the device" would be appreciated. And yes, I like Alan's idea, that would be much nicer overall for lots of functions like this. thanks, greg k-h