linux-kernel - Re: [PATCH] driver core: platform: Rename platform_get_irq_optional() to 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]
Date:   Tue, 25 Jan 2022 00:02:06 +0300
From:   Sergey Shtylyov <s.shtylyov@....ru>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
CC:     Andrew Lunn <andrew@...n.ch>, Ulf Hansson <ulf.hansson@...aro.org>,
        Vignesh Raghavendra <vigneshr@...com>,
        KVM list <kvm@...r.kernel.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        <linux-iio@...r.kernel.org>,
        "Linus Walleij" <linus.walleij@...aro.org>,
        Amit Kucheria <amitk@...nel.org>,
        "ALSA Development Mailing List" <alsa-devel@...a-project.org>,
        Jaroslav Kysela <perex@...ex.cz>,
        Guenter Roeck <groeck@...omium.org>,
        Thierry Reding <thierry.reding@...il.com>,
        MTD Maling List <linux-mtd@...ts.infradead.org>,
        Linux I2C <linux-i2c@...r.kernel.org>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        <linux-phy@...ts.infradead.org>, Jiri Slaby <jirislaby@...nel.org>,
        <openipmi-developer@...ts.sourceforge.net>,
        "Khuong Dinh" <khuong@...amperecomputing.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Matthias Schiffer <matthias.schiffer@...tq-group.com>,
        Joakim Zhang <qiangqing.zhang@....com>,
        Kamal Dasu <kdasu.kdev@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Lee Jones <lee.jones@...aro.org>,
        "Bartosz Golaszewski" <brgl@...ev.pl>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Kishon Vijay Abraham I <kishon@...com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        "open list:SERIAL DRIVERS" <linux-serial@...r.kernel.org>,
        bcm-kernel-feedback-list <bcm-kernel-feedback-list@...adcom.com>,
        Zhang Rui <rui.zhang@...el.com>,
        Linux PWM List <linux-pwm@...r.kernel.org>,
        Robert Richter <rric@...nel.org>,
        Saravanan Sekar <sravanhome@...il.com>,
        Corey Minyard <minyard@....org>,
        Linux PM list <linux-pm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        John Garry <john.garry@...wei.com>,
        Peter Korsgaard <peter@...sgaard.com>,
        William Breathitt Gray <vilhelm.gray@...il.com>,
        Mark Gross <markgross@...nel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Alex Williamson <alex.williamson@...hat.com>,
        Mark Brown <broonie@...nel.org>,
        Borislav Petkov <bp@...en8.de>,
        "Sebastian Reichel" <sre@...nel.org>,
        Eric Auger <eric.auger@...hat.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Takashi Iwai <tiwai@...e.com>,
        <platform-driver-x86@...r.kernel.org>,
        Benson Leung <bleung@...omium.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        <linux-edac@...r.kernel.org>, Tony Luck <tony.luck@...el.com>,
        Mun Yew Tham <mun.yew.tham@...el.com>,
        Hans de Goede <hdegoede@...hat.com>,
        <netdev@...r.kernel.org>,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
        Cornelia Huck <cohuck@...hat.com>,
        "Linux MMC List" <linux-mmc@...r.kernel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        linux-spi <linux-spi@...r.kernel.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
        Vinod Koul <vkoul@...nel.org>,
        "James Morse" <james.morse@....com>,
        Zha Qipeng <qipeng.zha@...el.com>,
        "Pengutronix Kernel Team" <kernel@...gutronix.de>,
        Richard Weinberger <richard@....at>,
        Niklas Söderlund <niklas.soderlund@...natech.se>,
        <linux-mediatek@...ts.infradead.org>,
        Brian Norris <computersforpeace@...il.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: Re: [PATCH] driver core: platform: Rename platform_get_irq_optional()
 to platform_get_irq_silent()

Hello!

On 1/24/22 6:01 PM, Andy Shevchenko wrote:

>>>>>>> It'd certainly be good to name anything that doesn't correspond to one
>>>>>>> of the existing semantics for the API (!) something different rather
>>>>>>> than adding yet another potentially overloaded meaning.
>>>>>>
>>>>>> It seems we're (at least) three who agree about this. Here is a patch
>>>>>> fixing the name.
>>>>>
>>>>> And similar number of people are on the other side.
>>>>
>>>> If someone already opposed to the renaming (and not only the name) I
>>>> must have missed that.
>>>>
>>>> So you think it's a good idea to keep the name
>>>> platform_get_irq_optional() despite the "not found" value returned by it
>>>> isn't usable as if it were a normal irq number?
>>>
>>> I meant that on the other side people who are in favour of Sergey's patch.
>>> Since that I commented already that I opposed the renaming being a standalone
>>> change.
>>>
>>> Do you agree that we have several issues with platform_get_irq*() APIs?
[...]
>>> 2. The vIRQ0 handling: a) WARN() followed by b) returned value 0
>>
>> I'm happy with the vIRQ0 handling. Today platform_get_irq() and it's
>> silent variant returns either a valid and usuable irq number or a
>> negative error value. That's totally fine.
> 
> It might return 0.
> Actually it seems that the WARN() can only be issued in two cases:
> - SPARC with vIRQ0 in one of the array member
> - fallback to ACPI for GPIO IRQ resource with index 0

   You have probably missed the recent discovery that arch/sh/boards/board-aps4*.c
causes IRQ0 to be passed as a direct IRQ resource?

> But the latter is bogus, because it would mean a bug in the ACPI code.

   Worth changing >= 0 to > 0 there, maybe?

> The bottom line here is the SPARC case. Anybody familiar with the platform
> can shed a light on this. If there is no such case, we may remove warning
> along with ret = 0 case from platfrom_get_irq().

   I'm afraid you're too fast here... :-)
   We'll have a really hard time if we continue to allow IRQ0 to be returned by
platform_get_irq() -- we'll have oto fileter it out in the callers then...

>>> 3. The specific cookie for "IRQ not found, while no error happened" case
>>
>> Not sure what you mean here. I have no problem that a situation I can
>> cope with is called an error for the query function. I just do error
>> handling and continue happily. So the part "while no error happened" is
>> irrelevant to me.
> 
> I meant that instead of using special error code, 0 is very much good for
> the cases when IRQ is not found. It allows to distinguish -ENXIO from the
> low layer from -ENXIO with this magic meaning.

   I don't see how -ENXIO can trickle from the lower layers, frankly...

[...]

MBR, Sergey