Re: [PATCH v2 5/8] rtc: isl12022: implement RTC_VL_READ ioctl

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Alessandro Zummo <a.zummo@towertech.it>,
	devicetree@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 5/8] rtc: isl12022: implement RTC_VL_READ ioctl
Date: Thu, 15 Jun 2023 13:58:16 +0300	[thread overview]
Message-ID: <ZIruyH5hpyboGwLU@smile.fi.intel.com> (raw)
In-Reply-To: <bd17c1a4-6102-3d93-5494-89fdb0a346e5@rasmusvillemoes.dk>

On Thu, Jun 15, 2023 at 12:53:24PM +0200, Rasmus Villemoes wrote:
> On 14/06/2023 17.13, Andy Shevchenko wrote:
> > When reading such a code the following questions are arisen:
> > 1) Can the positive return value be the case?
> > 2) If so, what is the meaning of a such?
> > 3) Why do we not care about it?
> > 
> > All this can simply gone if we use
> > 
> > 	ret = foo(...);
> > 	if (ret)
> > 		return ret;
> > 
> > As it's clear that whatever is non-zero we accept as something to be promoted
> > to the upper layer. I hope this explains my position.
> 
> But we're in a context (in this case an ->ioctl method) where _our_
> caller expects 0/-ESOMETHING, so returning something positive would be a
> bug - i.e., either way of spelling that if(), the reader must know that
> foo() also has those 0/-ESOMETHING semantics.

I totally understand this. But then it's either problem of regmap API
documentation or API itself. I.o.w. not _your_ problem.

> I honestly didn't think much about it, but looking at the existing code
> and the stuff I add, all other places actually do 'if (ret)', so I've
> updated this site for consistency.

Thank you!

-- 
With Best Regards,
Andy Shevchenko