linux-kernel - Re: [PATCH] gpio: arizona: put pm

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Date:   Fri, 5 Jun 2020 14:14:38 +0200
From:   Markus Elfring <Markus.Elfring@....de>
To:     Navid Emamdoost <navid.emamdoost@...il.com>,
        linux-gpio@...r.kernel.org, patches@...nsource.cirrus.com
Cc:     Navid Emamdoost <emamd001@....edu>, Kangjie Lu <kjlu@....edu>,
        Stephen McCamant <smccaman@....edu>,
        Qiushi Wu <wu000273@....edu>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Charles Keepax <ckeepax@...nsource.cirrus.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        kernel-janitors@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] gpio: arizona: put pm_runtime in case of failure

I recommend to replace the word “pm_runtime” by the
alternative “PM run time system” in the patch subject.

> Calling pm_runtime_get_sync increments the counter even in case of
> failure, causing incorrect ref count if pm_runtime_put is not called in
> error handling paths.

Should the term “reference count” be used here?

> Call pm_runtime_put if pm_runtime_get_sync fails.

The diff hunks show an other function name.

…
> +++ b/drivers/gpio/gpio-arizona.c
> @@ -64,6 +64,7 @@  static int arizona_gpio_get(struct gpio_chip *chip, unsigned offset)
>  		ret = pm_runtime_get_sync(chip->parent);
>  		if (ret < 0) {
>  			dev_err(chip->parent, "Failed to resume: %d\n", ret);
> +			pm_runtime_put_autosuspend(chip->parent);
>  			return ret;
>  		}

You propose to use identical statements in three if branches.
Please add a corresponding jump target for better exception handling.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/coding-style.rst?id=435faf5c218a47fd6258187f62d9bb1009717896#n455

Would you like to add the tag “Fixes” to the commit message?

I find it amazing how many questionable implementation details
you pointed out recently.
Were these contributions triggered by an evolving source code analysis
tool like CheQ?
https://github.com/umnsec/cheq/

Regards,
Markus