From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932339Ab0JZPAr (ORCPT ); Tue, 26 Oct 2010 11:00:47 -0400 Received: from mailout1.w1.samsung.com ([210.118.77.11]:48071 "EHLO mailout1.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754095Ab0JZPAp convert rfc822-to-8bit (ORCPT ); Tue, 26 Oct 2010 11:00:45 -0400 Date: Tue, 26 Oct 2010 17:03:06 +0200 From: =?utf-8?B?TWljaGHFgiBOYXphcmV3aWN6?= Subject: Re: [PATCH 1/7] USB: gadget: file_storage: put_device() in error recovery In-reply-to: To: Alan Stern Cc: Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Michal Nazarewicz 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/10.62 (Linux) References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 26 Oct 2010 16:09:27 +0200, Alan Stern wrote: > On Tue, 26 Oct 2010, Michal Nazarewicz wrote: >> This commit fixes some issues with File-backed Storage Gadget >> error recovery when registering LUN's devices. >> >> First of all, when device_register() fails the device still >> needs to be put. However, because lun_release() decreases >> fsg->ref reference counter the counter must be incremented >> beforehand. > > Correct. > >> Second of all, after any of the device_create_file()s fails, >> device_unregister() is called which in turn (indirectly) calls >> lun_release() which decrements fsg->ref. So, again, the >> reference counter must be incremented beforehand. > > Correct. > >> Lastly, if the first or the second device_create_file() >> succeeds, the files are never removed. To fix it, >> device_remove_file() needs to be called. This is done by >> simply marking LUN as registered prior to creating files so >> that fsg_unbind() can handle removing files. > > Correct. >> Hope I'm not late for 37? > > No doubt it is too late to get into the merge window. Ah, yes, that what I meant. I was hoping to get the whole set in -rc1, since some of the patches are purely coding style fixes. >> diff --git a/drivers/usb/gadget/file_storage.c b/drivers/usb/gadget/file_storage.c >> index d4fdf65..e0504a1 100644 >> --- a/drivers/usb/gadget/file_storage.c >> +++ b/drivers/usb/gadget/file_storage.c >> @@ -3392,21 +3392,19 @@ static int __init fsg_bind(struct usb_gadget *gadget) >> dev_set_name(&curlun->dev,"%s-lun%d", >> dev_name(&gadget->dev), i); >> >> - if ((rc = device_register(&curlun->dev)) != 0) { >> + kref_get(&fsg->ref); >> + rc = device_register(&curlun->dev); >> + if (rc) { >> INFO(fsg, "failed to register LUN%d: %d\n", i, rc); >> - goto out; >> - } >> - if ((rc = device_create_file(&curlun->dev, >> - &dev_attr_ro)) != 0 || >> - (rc = device_create_file(&curlun->dev, >> - &dev_attr_nofua)) != 0 || >> - (rc = device_create_file(&curlun->dev, >> - &dev_attr_file)) != 0) { >> - device_unregister(&curlun->dev); >> + put_device(&curlun->dev); >> goto out; >> } >> curlun->registered = 1; >> - kref_get(&fsg->ref); >> + >> + if ((rc = device_create_file(&curlun->dev, &dev_attr_ro)) || >> + (rc = device_create_file(&curlun->dev, &dev_attr_nofua)) || >> + (rc = device_create_file(&curlun->dev, &dev_attr_file))) >> + goto out; > > As long as you're changing these anyway, you may as well use the style > most developers seem to prefer: > > rc = device_create_file(&curlun->dev, &dev_attr_ro); > if (rc) > goto out; > ... But then it'd be total of 9 lines consisting of three 3-line ifs. I decided that it would be more readable with a single if even though it is not compliant with coding style. What do you think? I can just resend it. > After all, you did the same thing in the device_register() call above. > Apart from this small matter, ACK. Thanks. -- 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--