Re: [PATCH v6 1/5] device property: Allow error pointer to be passed to fwnode APIs

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rob Herring" <robh@kernel.org>,
	linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
	devicetree@vger.kernel.org, "Daniel Scally" <djrscally@gmail.com>,
	"Heikki Krogerus" <heikki.krogerus@linux.intel.com>,
	"Sakari Ailus" <sakari.ailus@linux.intel.com>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Frank Rowand" <frowand.list@gmail.com>,
	"Len Brown" <lenb@kernel.org>, "Nuno Sá" <nuno.sa@analog.com>,
	"Michael Walle" <michael@walle.cc>
Subject: Re: [PATCH v6 1/5] device property: Allow error pointer to be passed to fwnode APIs
Date: Mon, 11 Apr 2022 18:46:07 +0300	[thread overview]
Message-ID: <YlRNPyxHcNRQE/5A@smile.fi.intel.com> (raw)
In-Reply-To: <YlQ69jMduq/evgTt@kroah.com>

On Mon, Apr 11, 2022 at 04:28:06PM +0200, Greg Kroah-Hartman wrote:
> On Mon, Apr 11, 2022 at 04:50:11PM +0300, Andy Shevchenko wrote:
> > On Fri, Apr 08, 2022 at 09:48:40PM +0300, Andy Shevchenko wrote:
> > > Some of the fwnode APIs might return an error pointer instead of NULL
> > > or valid fwnode handle. The result of such API call may be considered
> > > optional and hence the test for it is usually done in a form of
> > > 
> > > 	fwnode = fwnode_find_reference(...);
> > > 	if (IS_ERR(fwnode))
> > > 		...error handling...
> > > 
> > > Nevertheless the resulting fwnode may have bumped the reference count
> > > and hence caller of the above API is obliged to call fwnode_handle_put().
> > > Since fwnode may be not valid either as NULL or error pointer the check
> > > has to be performed there. This approach uglifies the code and adds
> > > a point of making a mistake, i.e. forgetting about error point case.
> > > 
> > > To prevent this, allow an error pointer to be passed to the fwnode APIs.
> > 
> > Rafael and Greg, if this okay for you, can the first three patches be
> > applied, so we will have at least the fix in and consider constification
> > a further work?
> 
> Give us a chance, you sent this on friday and are asking about it first
> thing Monday morning?
> 
> Please go and review other patches sent on the list to help us catch up.

OK! Reviewed (actually commented on) a few patches so far.

-- 
With Best Regards,
Andy Shevchenko