linux-kernel - Re: [PATCH v7 3/4] firmware: arm_scmi: Add SCMI v3.2 pincontrol protocol basic support

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Message-ID: <ZgwQn7DzrBh-aUVX@smile.fi.intel.com>
Date: Tue, 2 Apr 2024 17:05:19 +0300
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: Peng Fan <peng.fan@....com>
Cc: "Peng Fan (OSS)" <peng.fan@....nxp.com>,
	Sudeep Holla <sudeep.holla@....com>,
	Cristian Marussi <cristian.marussi@....com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Linus Walleij <linus.walleij@...aro.org>,
	Dan Carpenter <dan.carpenter@...aro.org>,
	"linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	Oleksii Moisieiev <oleksii_moisieiev@...m.com>
Subject: Re: [PATCH v7 3/4] firmware: arm_scmi: Add SCMI v3.2 pincontrol
 protocol basic support

On Tue, Apr 02, 2024 at 01:27:19PM +0000, Peng Fan wrote:
> > On Tue, Apr 02, 2024 at 10:22:23AM +0800, Peng Fan (OSS) wrote:

..

> > > +#include <linux/module.h>
> > > +#include <linux/scmi_protocol.h>
> > > +#include <linux/slab.h>
> > 
> > Please, follow IWYU principle, a lot of headers are missed.
> 
> ok. I will try to figure out. BTW, is there an easy way to filter
> out what is missed?

For you is much easier than to me as I'm not familiar with the code.
Basically you should know what you wrote :-)

But if you are asking about tooling, we would appreciate when somebody comes
with a such.

> > > +#include "common.h"
> > > +#include "protocols.h"

..

> > > +		ret = scmi_pinctrl_get_pin_info(ph, selector,
> > > +						&pi->pins[selector]);
> > 
> > It's netter as a single line.
> 
> I try to follow 80 max chars per SCMI coding style. If Sudeep and Cristian
> is ok, I could use a single line.

It's minor, but even before relaxation of 80 limit it was and is mentioned
in the documentation that you may go over if it increases readability.

> > > +		if (ret)
> > > +			return ret;
> > > +	}

..

> > > +static int scmi_pinctrl_protocol_init(const struct
> > > +scmi_protocol_handle *ph) {
> > > +	int ret;
> > > +	u32 version;
> > > +	struct scmi_pinctrl_info *pinfo;
> > > +
> > > +	ret = ph->xops->version_get(ph, &version);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	dev_dbg(ph->dev, "Pinctrl Version %d.%d\n",
> > > +		PROTOCOL_REV_MAJOR(version),
> > PROTOCOL_REV_MINOR(version));
> > > +
> > > +	pinfo = devm_kzalloc(ph->dev, sizeof(*pinfo), GFP_KERNEL);
> > > +	if (!pinfo)
> > > +		return -ENOMEM;
> > > +
> > > +	ret = scmi_pinctrl_attributes_get(ph, pinfo);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	pinfo->pins = devm_kcalloc(ph->dev, pinfo->nr_pins,
> > > +				   sizeof(*pinfo->pins), GFP_KERNEL);
> > > +	if (!pinfo->pins)
> > > +		return -ENOMEM;
> > > +
> > > +	pinfo->groups = devm_kcalloc(ph->dev, pinfo->nr_groups,
> > > +				     sizeof(*pinfo->groups), GFP_KERNEL);
> > > +	if (!pinfo->groups)
> > > +		return -ENOMEM;
> > > +
> > > +	pinfo->functions = devm_kcalloc(ph->dev, pinfo->nr_functions,
> > > +					sizeof(*pinfo->functions),
> > GFP_KERNEL);
> > > +	if (!pinfo->functions)
> > > +		return -ENOMEM;
> > > +
> > > +	pinfo->version = version;
> > > +
> > > +	return ph->set_priv(ph, pinfo, version);
> > 
> > Same comments as per previous version. devm_ here is simply wrong.
> > It breaks the order of freeing resources.
> > 
> > I.o.w. I see *no guarantee* that these init-deinit functions will be properly
> > called from the respective probe-remove. Moreover the latter one may also
> > have its own devm allocations (which are rightfully placed) and you get
> > completely out of control the resource management.
> 
> I see an old thread.
> https://lore.kernel.org/linux-arm-kernel/ZJ78hBcjAhiU+ZBO@e120937-lin/#t
> 
> The free in deinit is not to free the ones alloced in init, it is to free the ones
> alloced such as in scmi_pinctrl_get_function_info

Even messier than I thought. For bare minimum these two should be documented
and renamed accordingly that no-one will think that deinit is a counter part
of init.


-- 
With Best Regards,
Andy Shevchenko