linux-kernel - Re: [PATCH 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]
Date:   Wed, 19 Jan 2022 18:50:12 +0300
From:   Sergey Shtylyov <s.shtylyov@....ru>
To:     Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
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>,
        Liam Girdwood <lgirdwood@...il.com>,
        <linux-iio@...r.kernel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Amit Kucheria <amitk@...nel.org>,
        <alsa-devel@...a-project.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Sebastian Reichel <sre@...nel.org>,
        <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>,
        Lee Jones <lee.jones@...aro.org>,
        <openipmi-developer@...ts.sourceforge.net>,
        Saravanan Sekar <sravanhome@...il.com>,
        Khuong Dinh <khuong@...amperecomputing.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>,
        John Garry <john.garry@...wei.com>,
        "Robert Richter" <rric@...nel.org>,
        Zha Qipeng <qipeng.zha@...el.com>,
        Corey Minyard <minyard@....org>, <linux-pm@...r.kernel.org>,
        Peter Korsgaard <peter@...sgaard.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>,
        Borislav Petkov <bp@...en8.de>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Takashi Iwai <tiwai@...e.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Benson Leung <bleung@...omium.org>,
        <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>,
        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>,
        <linux-spi@...r.kernel.org>, <linux-renesas-soc@...r.kernel.org>,
        Vinod Koul <vkoul@...nel.org>,
        James Morse <james.morse@....com>,
        "Pengutronix Kernel Team" <kernel@...gutronix.de>,
        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 1/2] platform: make platform_get_irq_optional() optional

On 1/19/22 6:02 PM, Uwe Kleine-König 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>
>> [...]
>>
>>    Please don't merge this as yet, I'm going thru this patch once again
>> and have already found some sloppy code. :-/
> 
> Who would you expect to merge this? I would have expected Greg, but he

   Me too, it's his area, the message was addressed to Greg KH...

> seems to have given up this thread.

   You instill too much uncertainty in him. :-)

>>> diff --git a/drivers/char/ipmi/bt-bmc.c b/drivers/char/ipmi/bt-bmc.c
>>> index 7450904e330a..fdc63bfa5be4 100644
>>> --- a/drivers/char/ipmi/bt-bmc.c
>>> +++ b/drivers/char/ipmi/bt-bmc.c
>>> @@ -382,12 +382,14 @@ static int bt_bmc_config_irq(struct bt_bmc *bt_bmc,
>>>  	bt_bmc->irq = platform_get_irq_optional(pdev, 0);
>>>  	if (bt_bmc->irq < 0)
>>>  		return bt_bmc->irq;
>>> +	if (!bt_bmc->irq)
>>> +		return 0;
>>
>>    Hm, this is sloppy. Will recast and rebase to the -next branch.
> 
> I didn't think about what you mean with sloppy, but the code is
> equivalent to
> 
> 	if (bt_bmc->irq <= 0)
> 		return bt_bmc->irq;

   Exactly.

[...]
>>> diff --git a/drivers/edac/xgene_edac.c b/drivers/edac/xgene_edac.c
>>> index 2ccd1db5e98f..0d1bdd27cd78 100644
>>> --- a/drivers/edac/xgene_edac.c
>>> +++ b/drivers/edac/xgene_edac.c
>>> @@ -1917,7 +1917,7 @@ static int xgene_edac_probe(struct platform_device *pdev)
>>>  
>>>  		for (i = 0; i < 3; i++) {
>>>  			irq = platform_get_irq_optional(pdev, i);
>>
>>    Is *_optinal() even correct here?
> 
> _optinal isn't correct, _optional maybe is. :-)

   No. :-)

> Anyhow, look at e26124cd5f7099949109608845bba9e9bf96599c, the driver was
> fixed not to print two error messages and the wrong option was picked.

   I think this patch is wrong...

>>> -			if (irq < 0) {
>>> +			if (irq <= 0) {
>>>  				dev_err(&pdev->dev, "No IRQ resource\n");

   This is what needed to be thrown overboard... :-)

>>>  				rc = -EINVAL;
>>>  				goto out_err;
> 
> What's wrong here is that the return code is hardcoded ...

  This is wrong as well -- kills the deferred probing. I have 2 separate patches
for this driver now... just need some time to get 'em ready...

[...]
>>> index bdf924b73e47..51289700a7ac 100644
>>> --- a/drivers/power/supply/mp2629_charger.c
>>> +++ b/drivers/power/supply/mp2629_charger.c
>>> @@ -581,9 +581,9 @@ static int mp2629_charger_probe(struct platform_device *pdev)
>>>  	platform_set_drvdata(pdev, charger);
>>>  
>>>  	irq = platform_get_irq_optional(to_platform_device(dev->parent), 0);
>>
>>    Again, is *_optional() even correct here?
>>
>>> -	if (irq < 0) {
>>> +	if (irq <= 0) {
>>>  		dev_err(dev, "get irq fail: %d\n", irq);
>>> -		return irq;
>>> +		return irq < 0 ? irq : -ENXIO;
> 
> Ack, could be simplified by switching to platform_get_irq().

   Have a draft patch...

> Best regards
> Uwe

MBR, Sergey