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Date: Sat, 6 Apr 2024 17:07:17 +0100
From: Jonathan Cameron <jic23@kernel.org>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Nuno =?UTF-8?B?U8Oh?= <noname.nuno@gmail.com>, Nuno Sa
 <nuno.sa@analog.com>, Petr Mladek <pmladek@suse.com>, Lars-Peter Clausen
 <lars@metafoo.de>, Olivier Moysan <olivier.moysan@foss.st.com>, Jyoti
 Bhayana <jbhayana@google.com>, Chris Down <chris@chrisdown.name>, John
 Ogness <john.ogness@linutronix.de>, Greg Kroah-Hartman
 <gregkh@linuxfoundation.org>, linux-kernel@vger.kernel.org,
 linux-iio@vger.kernel.org
Subject: Re: [PATCH 3/4] iio: backend: make use of dev_errp_probe()
Message-ID: <20240406170717.31ab7e47@jic23-huawei>
In-Reply-To: <Zg7DWQtY6SP9E_1m@smile.fi.intel.com>
References: <20240404-dev-add_dev_errp_probe-v1-0-d18e3eb7ec3f@analog.com>
	<20240404-dev-add_dev_errp_probe-v1-3-d18e3eb7ec3f@analog.com>
	<Zg6bsS3WMvp-nY3S@smile.fi.intel.com>
	<9f91388faee750e16021f2c0544e7a158a16202b.camel@gmail.com>
	<Zg7DWQtY6SP9E_1m@smile.fi.intel.com>
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On Thu, 4 Apr 2024 18:12:25 +0300
Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:

> On Thu, Apr 04, 2024 at 04:58:27PM +0200, Nuno S=C3=A1 wrote:
> > On Thu, 2024-04-04 at 15:23 +0300, Andy Shevchenko wrote: =20
> > > On Thu, Apr 04, 2024 at 01:06:25PM +0200, Nuno Sa wrote: =20
> > > > Using dev_errp_probe() to simplify the code. =20
>=20
> ...
>=20
> > > > +	if (IS_ERR(fwnode))
> > > > +		return dev_errp_probe(dev, PTR_ERR(fwnode),
> > > > +				=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 "Cannot get Firmware reference\=
n"); =20
> > >=20
> > > ERR_CAST() seems quite good candidate to have here.
> > >=20
> > > 		return dev_errp_probe(dev, fwnode, "Cannot get Firmware
> > > reference\n");
> > >=20
> > > (Assuming dev_errp_probe() magically understands that, note you may h=
ave it as
> > > =C2=A0a macro and distinguish parameter type with _Generic() or so an=
d behave
> > > =C2=A0differently: ERR_PTR() vs. ERR_CAST(), see acpi_dev_hid_uid_mat=
ch()
> > > =C2=A0implementation, but also keep in mind that it doesn't distingui=
sh NULL/0,
> > > there
> > > =C2=A0is a patch available in the mailing list to fix that, though.) =
=20
> >=20
> > Do we care that much for going with that trouble? =20
>=20
> I don't think we do. We are not supposed to be called with ret =3D=3D 0/N=
ULL.
> That's why I pointed out to the current version.
>=20
> > I understand like this we go
> > PTR_ERR() to then comeback to ERR_PTR() but this for probe() which is n=
ot a
> > fastpath. So perhaps we could just keep it simple? =20
>=20
> It's not about performance, it's about readability. See the difference be=
tween
> yours and mine.
>=20

You are suggesting making it transparently take an error ptr or an integer?
Whilst clever, I'm not seeing that as a good idea for readability / reviewa=
bility.
I expect something that looks like a function to take the same parameters (=
other vargs)
always.  _Generic messes with that.

Maybe I just don't like to learn new things!  If consensus comes down in fa=
vour
of _Generic trickery then I'll get used to it eventually.

Jonathan