linux-kernel - Re: [PATCH v8 2/3] regulator: Add devres version of of_regulator_get

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: <CAGXv+5Gf9+rc+vLcr-JFhO561G8dw38ksV3drat+DyCfWEVakQ@mail.gmail.com>
Date: Thu, 26 Sep 2024 16:43:52 +0800
From: Chen-Yu Tsai <wenst@...omium.org>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Ulf Hansson <ulf.hansson@...aro.org>, Matthias Brugger <matthias.bgg@...il.com>, 
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, Mark Brown <broonie@...nel.org>, 
	devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	linux-pm@...r.kernel.org, Douglas Anderson <dianders@...omium.org>, 
	Johan Hovold <johan@...nel.org>, Pablo Sun <pablo.sun@...iatek.com>, 
	Macpaul Lin <macpaul.lin@...iatek.com>, 
	Sebastian Reichel <sebastian.reichel@...labora.com>
Subject: Re: [PATCH v8 2/3] regulator: Add devres version of of_regulator_get_optional()

On Wed, Sep 25, 2024 at 6:56 PM Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
>
> On Wed, Sep 25, 2024 at 05:38:05PM +0800, Chen-Yu Tsai wrote:
> > There are existing uses for a devres version of of_regulator_get_optional()
> > in power domain drivers. On MediaTek platforms, power domains may have
> > regulator supplies tied to them. The driver currently tries to use
> > devm_regulator_get() to not have to manage the lifecycle, but ends up
> > doing it in a very hacky way by replacing the device node of the power
> > domain controller device to the device node of the power domain that is
> > currently being registered, getting the supply, and reverting the device
> > node.
> >
> > Provide a better API so that the hack can be replaced.
>
> ...
>
> > +#if IS_ENABLED(CONFIG_OF)
>
> Do we really need this?

What's the point of going through devres_* stuff if we already know
_of_regulator_get() is going to fail anyway?

Also, _of_regulator_get() does not have a stub version for !CONFIG_OF.

> > +static struct regulator *_devm_of_regulator_get(struct device *dev, struct device_node *node,
> > +                                             const char *id, int get_type)
> > +{
> > +     struct regulator **ptr, *regulator;
> > +
> > +     ptr = devres_alloc(devm_regulator_release, sizeof(*ptr), GFP_KERNEL);
> > +     if (!ptr)
> > +             return ERR_PTR(-ENOMEM);
> > +
> > +     regulator = _of_regulator_get(dev, node, id, get_type);
> > +     if (!IS_ERR(regulator)) {
> > +             *ptr = regulator;
> > +             devres_add(dev, ptr);
> > +     } else {
> > +             devres_free(ptr);
> > +     }
> > +
> > +     return regulator;
>
> Why not using devm_add_action() / devm_add_action_or_reset()
> (whichever suits better here)?

Cargo cult from _devm_regulator_get() in this file. However since this is
meant to share the same release function, both functions need to use the
same mechanism.

I could also argue that this is not an action, but an allocation, and so
devres_alloc() seems to make more sense.


ChenYu

> > +}
>
> > +#endif
>
> ...
>
> > +static inline struct regulator *__must_check devm_of_regulator_get_optional(struct device *dev,
> > +                                                                         struct device_node *node,
> > +                                                                         const char *id)
>
> I don't know the conventions here, but I find better to have it as
>
> static inline __must_check struct regulator *
> devm_of_regulator_get_optional(struct device *dev, struct device_node *node, const char *id)
>
> Similar to other stubs and declarations.

I don't think there are any conventions. This file already has three types:

1. Wrap the line with the function name on the second line
2. Wrap the arguments; wrapped arguments aligned to the left parenthesis.
3. Wrap the arguments; wrapped arguments aligned with aribtrary number of
   tabs.

I prefer the way I have put them.