netdev - Re: [PATCH v2 1/2] platform: make platform_get_irq

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20220214071351.pcvstrzkwqyrg536@pengutronix.de>
Date:   Mon, 14 Feb 2022 08:13:51 +0100
From:   Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
To:     Sergey Shtylyov <s.shtylyov@....ru>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        linux-kernel@...r.kernel.org, Andrew Lunn <andrew@...n.ch>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Vignesh Raghavendra <vigneshr@...com>,
        Jiri Slaby <jirislaby@...nel.org>, linux-iio@...r.kernel.org,
        Linus Walleij <linus.walleij@...aro.org>,
        Amit Kucheria <amitk@...nel.org>, alsa-devel@...a-project.org,
        Liam Girdwood <lgirdwood@...il.com>,
        linux-phy@...ts.infradead.org,
        Thierry Reding <thierry.reding@...il.com>,
        linux-mtd@...ts.infradead.org, linux-i2c@...r.kernel.org,
        linux-gpio@...r.kernel.org,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Guenter Roeck <groeck@...omium.org>, linux-spi@...r.kernel.org,
        Lee Jones <lee.jones@...aro.org>,
        openipmi-developer@...ts.sourceforge.net,
        Peter Korsgaard <peter@...sgaard.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Matthias Schiffer <matthias.schiffer@...tq-group.com>,
        kvm@...r.kernel.org, Kamal Dasu <kdasu.kdev@...il.com>,
        Richard Weinberger <richard@....at>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Kishon Vijay Abraham I <kishon@...com>,
        bcm-kernel-feedback-list@...adcom.com,
        linux-serial@...r.kernel.org, Jakub Kicinski <kuba@...nel.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        platform-driver-x86@...r.kernel.org, linux-pwm@...r.kernel.org,
        Zha Qipeng <qipeng.zha@...el.com>,
        Corey Minyard <minyard@....org>, linux-pm@...r.kernel.org,
        John Garry <john.garry@...wei.com>,
        William Breathitt Gray <vilhelm.gray@...il.com>,
        Mark Gross <markgross@...nel.org>,
        Hans de Goede <hdegoede@...hat.com>,
        Alex Williamson <alex.williamson@...hat.com>,
        Mark Brown <broonie@...nel.org>,
        linux-mediatek@...ts.infradead.org,
        Matthias Brugger <matthias.bgg@...il.com>,
        Takashi Iwai <tiwai@...e.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Benson Leung <bleung@...omium.org>,
        linux-arm-kernel@...ts.infradead.org,
        Mun Yew Tham <mun.yew.tham@...el.com>,
        Eric Auger <eric.auger@...hat.com>, netdev@...r.kernel.org,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
        Cornelia Huck <cohuck@...hat.com>, linux-mmc@...r.kernel.org,
        Joakim Zhang <qiangqing.zhang@....com>,
        Oleksij Rempel <linux@...pel-privat.de>,
        linux-renesas-soc@...r.kernel.org, Vinod Koul <vkoul@...nel.org>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Niklas Söderlund <niklas.soderlund@...natech.se>,
        Brian Norris <computersforpeace@...il.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: Re: [PATCH v2 1/2] platform: make platform_get_irq_optional()
 optional

On Sat, Feb 12, 2022 at 11:16:30PM +0300, Sergey Shtylyov wrote:
> This patch is based on the former Andy Shevchenko's patch:
> 
> https://lore.kernel.org/lkml/20210331144526.19439-1-andriy.shevchenko@linux.intel.com/
> 
> Currently platform_get_irq_optional() returns an error code even if IRQ
> resource simply has not been found.  It prevents the callers from being
> error code agnostic in their error handling:
> 
> 	ret = platform_get_irq_optional(...);
> 	if (ret < 0 && ret != -ENXIO)
> 		return ret; // respect deferred probe
> 	if (ret > 0)
> 		...we get an IRQ...
> 
> All other *_optional() APIs seem to return 0 or NULL in case an optional
> resource is not available.  Let's follow this good example, so that the
> callers would look like:
> 
> 	ret = platform_get_irq_optional(...);
> 	if (ret < 0)
> 		return ret;
> 	if (ret > 0)
> 		...we get an IRQ...
> 
> Reported-by: Matthias Schiffer <matthias.schiffer@...tq-group.com>
> Signed-off-by: Sergey Shtylyov <s.shtylyov@....ru>

While this patch is better than v1, I still don't like it for the
reasons discussed for v1. (i.e. 0 isn't usable as a dummy value which I
consider the real advantage for the other _get_optional() functions.)

Apart from that, I think the subject is badly chosen. With "Make
somefunc() optional" I would expect that you introduce a Kconfig symbol
that results in the function not being available when disabled.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

Download attachment "signature.asc" of type "application/pgp-signature" (489 bytes)