Re: [PATCH v4 4/6] iio: light: stk3310: use dev_err_probe where possible

["Nuno Sá" <noname.nuno@gmail.com>]

On Tue, 2024-11-12 at 11:15 +0100, Uwe Kleine-König wrote:
> Hello Andy, hello Aren,
> 
> On Mon, Nov 11, 2024 at 11:44:51AM +0200, Andy Shevchenko wrote:
> > On Sun, Nov 10, 2024 at 04:34:30PM -0500, Aren wrote:
> > > On Sun, Nov 10, 2024 at 09:52:32PM +0200, Andy Shevchenko wrote:
> > > > Sun, Nov 10, 2024 at 02:14:24PM -0500, Aren kirjoitti:
> > 
> > You can do it differently
> > 
> > #define
> > STK3310_REGFIELD(name)							\
> > do
> > {										\
> > 	data->reg_##name
> > =							\
> > 		devm_regmap_field_alloc(dev, regmap,
> > stk3310_reg_field_##name);	\
> > 	if (IS_ERR(data-
> > >reg_##name))						\
> > 		return dev_err_probe(dev, PTR_ERR(data-
> > >reg_##name),		\
> > 				     "reg field alloc
> > failed.\n");		\
> > } while (0)
> > 
> > > #define STK3310_REGFIELD(name)
> > > ({						\
> > > 	data->reg_##name = devm_regmap_field_alloc(dev,
> > > regmap,			\
> > > 						  
> > > stk3310_reg_field_##name);   \
> > > 	if (IS_ERR(data-
> > > >reg_##name))						\
> > > 		return dev_err_probe(dev, PTR_ERR(data-
> > > >reg_##name),		\
> > > 				     "reg field alloc
> > > failed\n");		\
> > > })
> > 
> > I am against unneeded use of GNU extensions.
> > 
> > > > > replacing "do { } while (0)" with "({ })" and deindenting could make
> > > > > enough room to clean this up the formatting of this macro though.
> > > > 
> > > > do {} while (0) is C standard, ({}) is not.
> > > 
> > > ({ }) is used throughout the kernel, and is documented as such[1]. I
> > > don't see a reason to avoid it, if it helps readability.
> > 
> > I don't see how it makes things better here, and not everybody is familiar with
> > the concept even if it's used in the kernel here and there. Also if a tool is
> > being used in one case it doesn't mean it's suitable for another.
> 
> Just to throw in my subjective view here: I don't expect anyone with
> some base level knowledge of C will have doubts about the semantics of
> ({ ... }) and compared to that I find do { ... } while (0) less optimal,
> because it's more verbose and when spotting the "do {" part, the
> semantic only gets clear when you also see the "while (0)". Having said
> that I also dislike the "do" starting on column 0, IMHO the RHS of the
> #define should be intended.
> 
> So if you ask me, this is not an unneeded use of an extension. The
> extension is used to improve readabilty and I blame the C standard to
> not support this syntax.
> 
> While I'm in critics mode: I consider hiding a return in a macro bad
> style.
> 

Not commenting on the debate between using the extension or not but I totally agree
with Uwe about hiding the return in the macro.

- Nuno Sá
>