Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757309Ab3EHQhR (ORCPT ); Wed, 8 May 2013 12:37:17 -0400 Received: from cantor2.suse.de ([195.135.220.15]:38773 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756351Ab3EHQhA (ORCPT ); Wed, 8 May 2013 12:37:00 -0400 Date: Wed, 08 May 2013 18:37:01 +0200 Message-ID: From: Takashi Iwai To: Ming Lei Cc: linux-kernel@vger.kernel.org, Greg Kroah-Hartman Subject: Re: [PATCH 1/3] firmware: Avoid superfluous usermodehelper lock In-Reply-To: References: <1367996197-32748-1-git-send-email-tiwai@suse.de> <1367996197-32748-2-git-send-email-tiwai@suse.de> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/24.2 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1506 Lines: 38 At Wed, 08 May 2013 18:21:11 +0200, Takashi Iwai wrote: > > At Wed, 8 May 2013 23:52:02 +0800, > Ming Lei wrote: > > > > On Wed, May 8, 2013 at 2:56 PM, Takashi Iwai wrote: > > > When a firmware file can be loaded directly, there is no good reason > > > to lock usermodehelper. It's needed only when the direct fw load > > > fails and falls back to the user-mode helper. > > > > I remembered that we discussed the problem before, :-) > > > > Some crazy drivers might call request_firmware inside resume callback > > (for example, USB devices might be rebind in resume), with > > usermodehelper_read_lock, we can find the mistake easily and log it. > > > > I am wondering if it is good to remove the usermodehelper lock. > > > > Could you let us know any benefit to do it? > > Well, the question is whether usermodehelper lock is really an > appropriate stuff for *checking* the availability of direct fs > access. I find it doesn't fit well any longer, in the situation where > no actual user-space call is needed. Though, I'm not quite sure which > lock or flag can be used instead... In other words, the first patch is no essential part of the fix. I can revisit the second patch without this one and resend if preferred. Takashi -- 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/