From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754590AbcHXIWJ (ORCPT ); Wed, 24 Aug 2016 04:22:09 -0400 Received: from torres.puc.rediris.es ([130.206.18.22]:45230 "EHLO torres.puc.rediris.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753356AbcHXIUa (ORCPT ); Wed, 24 Aug 2016 04:20:30 -0400 X-Envelope-From: paubert@iram.es Date: Wed, 24 Aug 2016 10:17:38 +0200 From: Gabriel Paubert To: mcgrof@kernel.org Cc: ming.lei@canonical.com, akpm@linux-foundation.org, gregkh@linuxfoundation.org, dmitry.torokhov@gmail.com, linux-doc@vger.kernel.org, Gilles.Muller@lip6.fr, tiwai@suse.de, Daniel Vetter , Alessandro Rubini , stephen.boyd@linaro.org, bjorn.andersson@linaro.org, teg@jklm.no, chunkeey@googlemail.com, cocci@systeme.lip6.fr, jwboyer@fedoraproject.org, Jonathan Corbet , Kevin Cernekee , Thierry Martinez , linux-serial@vger.kernel.org, jslaby@suse.com, zohar@linux.vnet.ibm.com, arend.vanspriel@broadcom.com, linuxppc-dev@lists.ozlabs.org, Kees Cook , hauke@hauke-m.de, nicolas.palix@imag.fr, Abhay_Salunke@dell.com, Julia.Lawall@lip6.fr, broonie@kernel.org, j.anaszewski@samsung.com, kvalo@codeaurora.org, dhowells@redhat.com, dwmw2@infradead.org, markivx@codeaurora.org, daniel.wagner@bmw-carit.de, linux-kernel@vger.kernel.org, luto@amacapital.net, mmarek@suse.com, rpurdie@rpsys.net, johannes@sipsolutions.net, fengguang.wu@intel.com, torvalds@linux-foundation.org Subject: Re: [PATCH v3 2/5] firmware: annotate thou shalt not request fw on init or probe Message-ID: <20160824081738.GA8991@visitor2.iram.es> References: <1466117661-22075-1-git-send-email-mcgrof@kernel.org> <1471999507-913-1-git-send-email-mcgrof@kernel.org> <1471999507-913-3-git-send-email-mcgrof@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1471999507-913-3-git-send-email-mcgrof@kernel.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-Spamina-Bogosity: Ham Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 23, 2016 at 05:45:04PM -0700, mcgrof@kernel.org wrote: [snip] > --- > Documentation/firmware_class/README | 20 ++++ > drivers/base/Kconfig | 2 +- > .../request_firmware-avoid-init-probe-init.cocci | 130 +++++++++++++++++++++ > 3 files changed, 151 insertions(+), 1 deletion(-) > create mode 100644 scripts/coccinelle/api/request_firmware-avoid-init-probe-init.cocci > > diff --git a/Documentation/firmware_class/README b/Documentation/firmware_class/README > index cafdca8b3b15..056d1cb9d365 100644 > --- a/Documentation/firmware_class/README > +++ b/Documentation/firmware_class/README > @@ -93,6 +93,26 @@ > user contexts to request firmware asynchronously, but can't be called > in atomic contexts. > > +Requirements: > +============= > + > +You should avoid at all costs requesting firmware on both init and probe paths > +of your device driver. Reason for this is the complexity needed to ensure a > +firmware will be available for a driver early in boot through different > +build configurations. Consider built-in drivers needing firmware early, or > +consider a driver assuming it will only get firmware after pivot_root(). > + > +Drivers that really need firmware early should use stuff the firmware in Minor grammatical nit: s/use// > +initramfs or consider using CONFIG_EXTRA_FIRMWARE. Using initramfs is much > +more portable to more distributions as not all distributions wish to enable > +CONFIG_EXTRA_FIRMWARE. Should a driver require the firmware being built-in > +it should depend on CONFIG_EXTRA_FIRMWARE. There is no current annotation for > +requiring a firmware on initramfs. > + > +If you're a maintainer you can help police this with: > + > +$ export COCCI=scripts/coccinelle/api/request_firmware-avoid-init-probe-init.cocci > +$ make coccicheck MODE=report > > about in-kernel persistence: > ---------------------------