From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1753334AbcJEAYo (ORCPT <rfc822;w@1wt.eu>);
        Tue, 4 Oct 2016 20:24:44 -0400
Received: from mail.kernel.org ([198.145.29.136]:54760 "EHLO mail.kernel.org"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1750842AbcJEAYm (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Tue, 4 Oct 2016 20:24:42 -0400
MIME-Version: 1.0
In-Reply-To: <CA+55aFx=hzXhrHQO4-0Jnd1ML4dismQ8qggvSp0yccSRW6qH3A@mail.gmail.com>
References: <20160902235916.GO3296@wotan.suse.de> <20160903002014.GP3296@wotan.suse.de>
 <CA+55aFy4_QLYiQxtKpq0FJD7eSBRZ8nXS=Ruuz1TYodHdE_dCA@mail.gmail.com>
 <CAKdAkRSQmz3FoP8Z2ONm7-_A9RHF2Ox6snaCpsyS6HA7=+RerQ@mail.gmail.com>
 <CA+55aFz4q5peXAeY9h8o3he7R=wXrBSYkOjMM9TehOw=pPoS+Q@mail.gmail.com>
 <20160903174939.GB32345@dtor-ws> <CA+55aFwLrXRUO9n75Sthu+g73BEjskAgUkguyLwU=JA_PNzdOQ@mail.gmail.com>
 <CAKdAkRTv5Fv54wetBqkS+EyEuP_k5exJat+QXBLtTkFLO_-maQ@mail.gmail.com>
 <2deae6da-dd43-7bff-e1fd-ffd26946b928@intel.com> <CAKdAkRQhEdaP+z02DQ9nighSg_N8R+Dnkv7x3EkYc_YmO_jW4g@mail.gmail.com>
 <20161005000008.GY3296@wotan.suse.de> <CA+55aFx=hzXhrHQO4-0Jnd1ML4dismQ8qggvSp0yccSRW6qH3A@mail.gmail.com>
From: "Luis R. Rodriguez" <mcgrof@kernel.org>
Date: Tue, 4 Oct 2016 17:24:14 -0700
X-Gmail-Original-Message-ID: <CAB=NE6UXX+=nnJcOgO7NWudmDR3bESVO-mQrqG26Gpd4z71xqA@mail.gmail.com>
Message-ID: <CAB=NE6UXX+=nnJcOgO7NWudmDR3bESVO-mQrqG26Gpd4z71xqA@mail.gmail.com>
Subject: Re: [RFC] fs: add userspace critical mounts event support
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        "Herbert, Marc" <marc.herbert@intel.com>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        Jacek Anaszewski <j.anaszewski@samsung.com>,
        David Woodhouse <dwmw2@infradead.org>,
        Christian Lamparter <chunkeey@googlemail.com>,
        Julia Lawall <Julia.Lawall@lip6.fr>,
        Andrew Morton <akpm@linux-foundation.org>,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
        Mimi Zohar <zohar@linux.vnet.ibm.com>,
        Andy Lutomirski <luto@amacapital.net>,
        Richard Purdie <rpurdie@rpsys.net>,
        Wu Fengguang <fengguang.wu@intel.com>,
        Johannes Berg <johannes@sipsolutions.net>,
        Michal Marek <mmarek@suse.com>, Hauke Mehrtens <hauke@hauke-m.de>,
        Mark Brown <broonie@kernel.org>, Jiri Slaby <jslaby@suse.com>,
        Ming Lei <ming.lei@canonical.com>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Felix Fietkau <nbd@nbd.name>, Roman Pen <r.peniaev@gmail.com>,
        Greg KH <gregkh@linuxfoundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Vikram Mulukutla <markivx@codeaurora.org>,
        Stephen Boyd <stephen.boyd@linaro.org>, Takashi Iwai <tiwai@suse.de>,
        Jeff Mahoney <jeffm@suse.com>, Hariprasad S <hariprasad@chelsio.com>,
        Benjamin Poirier <bpoirier@suse.de>,
        Josh Triplett <josh@joshtriplett.org>
Content-Type: text/plain; charset=UTF-8
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Tue, Oct 4, 2016 at 5:12 PM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
> On Tue, Oct 4, 2016 at 5:00 PM, Luis R. Rodriguez <mcgrof@kernel.org> wrote:
>>
>> I am not sure how/why a firmware loading daemon would be a better
>> idea now. What Marc describes that Josh proposed with signals for
>> userspcae seems more aligned with what we likely need
>
> Quite frankly, I doubt you want a signal.
>
> You will want to have some way to specify where the firmware files
> are. Right now we have "fw_path[]" which is hardcoded except for the
> first entry that can be set as a module parameter. But you'd probably
> want to expand on that, which implies some /sys or /proc interface.
>
> And once you do that, wouldn't it make more sense to just make the
> "update the firmware path /proc/sys/kernel/fw_path file" make things
> re-search for firmware?

We can, but re-searching for firmware assumes we cache pending
firmware, we currently don't, we just either process sync or async
firmware requests.

> In other words, the interface has to be something *sensible*. Not some
> idiotic ad-hoc "send a signal" (of which that stupid original patch
> was just a very odd example).

Note that the races are beyond firmware, so all
kernel_read_file_from_path() users, as such re-using such old /sys/
interafeces for firmware will not suffice to cover all ground now for
the same race for other possible users.

 Luis