From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755439Ab0ELJxX (ORCPT ); Wed, 12 May 2010 05:53:23 -0400 Received: from mailout1.w1.samsung.com ([210.118.77.11]:19274 "EHLO mailout1.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755393Ab0ELJxU convert rfc822-to-8bit (ORCPT ); Wed, 12 May 2010 05:53:20 -0400 Date: Wed, 12 May 2010 11:53:45 +0200 From: =?utf-8?B?TWljaGHFgiBOYXphcmV3aWN6?= Subject: Re: [PATCH] USB: gadget: f_mass_storage: fix in fsg_common_init() error recovery In-reply-to: <70376CA23424B34D86F1C7DE6B9973430254343ABB@VSHINMSMBX01.vshodc.lntinfotech.com> To: Viral Mehta , "linux-usb@vger.kernel.org" Cc: Kyungmin Park , Marek Szyprowski , "linux-kernel@vger.kernel.org" Message-id: Organization: Samsung Electronics MIME-version: 1.0 Content-type: text/plain; charset=utf-8; format=flowed; delsp=yes Content-transfer-encoding: 8BIT User-Agent: Opera Mail/10.10 (Linux) References: <994e1bf34d3b6f1fbc58c0f7ce61c7f258208ddd.1273651956.git.mina86@mina86.com> <70376CA23424B34D86F1C7DE6B9973430254343ABA@VSHINMSMBX01.vshodc.lntinfotech.com> <70376CA23424B34D86F1C7DE6B9973430254343ABB@VSHINMSMBX01.vshodc.lntinfotech.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >> fsg_common_init() as a first argument takes a pointer to a fsg_common >> structure which, if not NULL, is reused and it is then assumed that >> caller is responsible far maintaining allocation and deallocation of >> this structure. >> >> The idea is that one can do: >> >> static struct fsg_common fsg_common; >> /* ... */ >> fsg_common_init(&fsg_common, cdev, fsg_config); >> >> or allocate fsg_common structure as a part of a larger structure. In such >> cases kfree() cannot be called on the object. Which case we are dealing >> with is indicated by the common->free_storage_on_release flag. >> fsg_common_release() consults it and either calls or does not call krfee(). On Wed, 12 May 2010 11:28:31 +0200, Viral Mehta wrote: > Oh, makes sense. All instances has fsg_common_init(0, ...) and so i just missed... I'm preparing a some patches for g_multi which change that. Also, a change for g_mass_storage which uses a static memory would be like 10 line patch which I may submit later. > But, still the central idea was, why should we go to whole error_release path which > really does removing device file and closing luns and etc. > However, it will not make any difference since curlun->nluns will be zero and so > there will be no loop in fsg_common_releas() function. The way I see it, it does not matter that much -- it's error recovery so we assume it's unlikely to happen and as such speed optimisation is not really needed here -- it's better to optimise for space and minimise the number of possible paths. > Apart from that, IMHO, > 2894 kfree(common->luns); > should crash in case if your error path is followed. > > common->luns is allocd > 2712 /* Create the LUNs, open their backing files, and register the > 2713 * LUN devices in sysfs. */ > 2714 curlun = kzalloc(nluns * sizeof *curlun, GFP_KERNEL); > 2715 if (!curlun) { > 2716 kfree(common); > 2717 return ERR_PTR(-ENOMEM); > 2718 } Yes, that's why the submitted patch changes that to "rc = -ENOMEM; goto errer_release;". -- Best regards, _ _ | Humble Liege of Serenely Enlightened Majesty of o' \,=./ `o | Computer Science, Michał "mina86" Nazarewicz (o o) +----[mina86*mina86.com]---[mina86*jabber.org]----ooO--(_)--Ooo--