Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760335Ab2EKOeM (ORCPT ); Fri, 11 May 2012 10:34:12 -0400 Received: from acsinet15.oracle.com ([141.146.126.227]:34769 "EHLO acsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757321Ab2EKOeJ (ORCPT ); Fri, 11 May 2012 10:34:09 -0400 Date: Fri, 11 May 2012 10:27:58 -0400 From: Konrad Rzeszutek Wilk To: "Liu, Jinsong" Cc: "'xen-devel@lists.xensource.com'" , "'linux-kernel@vger.kernel.org'" Subject: Re: [PATCH 3/3] Xen physical cpus interface Message-ID: <20120511142758.GA29677@phenom.dumpdata.com> References: <20120420192439.GA32170@phenom.dumpdata.com> <20120510145745.GO26152@phenom.dumpdata.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2037 Lines: 60 On Fri, May 11, 2012 at 01:12:13PM +0000, Liu, Jinsong wrote: > Liu, Jinsong wrote: > > Just notice your reply (so quick :) > > > > Agree and will update later, except 1 concern below. > > > > Konrad Rzeszutek Wilk wrote: > >>> > >>> Hmm, it's good if it's convenient to do it automatically via > >>> dev->release. However, dev container (pcpu) would be free at some > >>> other error cases, so I prefer do it 'manually'. > >> > >> You could also call pcpu_release(..) to do it manually. > >> > > > > that means kfree(pcpu) would be done twice at some error cases, do > > you think it really good? > > > > Ping. > > I think error recovery should be kept inside error logic level itself, if try to recover upper level error would bring trouble. > > In our example, there are 2 logic levels: > pcpu level (as container), and dev level (subfield used for sys) So you need to untangle free_pcpu from doing both. Meaning one does the SysFS and the other deals with free-ing the structure and removing itself from the list. > dev->release should only recover error occurred at dev/sys level, and the pcpu error should be recovered at pcpu level. > > If dev->release try to recover its container pcpu level error, like list_del/kfree(pcpu), it would make confusing. i.e., considering pcpu_sys_create(), 2 error cases: > device_register fail, and device_create_file fail --> how can the caller decide kfree(pcpu) or not? Then you should free it manually. But you can do this by a wrapper function: __pcpu_release(..) { .. /* Does the removing itself from the list and kfree the pcpu */ } pcpu_release(..) { struct pcpcu *p= container_of(..) __pcpu_release(p); } dev->release = &pcpu_release; > > So how about recover pcpu error manually and explicitly? > > Thanks, > Jinsong -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/