Date: Wed, 21 Nov 2012 11:09:08 +0100
From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
To: Grant Likely <grant.likely@secretlab.ca>
Cc: Arnd Bergmann <arnd@arndb.de>, Stephen Warren <swarren@wwwdotorg.org>,
        Josh Cartwright <josh.cartwright@gmail.com>,
        Stephen Warren <swarren@nvidia.com>, John Stultz <johnstul@us.ibm.com>,
        linux-kernel@vger.kernel.org, Rob Herring <rob.herring@calxeda.com>,
        linux-tegra@vger.kernel.org, Olof Johansson <olof@lixom.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH V4 1/3] of: introduce for_each_matching_node_and_match()
Message-ID: <20121121110908.64bc74cd@skate>
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	<201211210953.20552.arnd@arndb.de>
	<CACxGe6u5UBqVPrBqwn9rhjuBx4uCuuHKU=FcvSp0GJ2G8ogSNQ@mail.gmail.com>
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On Wed, 21 Nov 2012 10:06:16 +0000, Grant Likely wrote:
> On Wed, Nov 21, 2012 at 9:53 AM, Arnd Bergmann <arnd@arndb.de> wrote:
> > On Tuesday 20 November 2012, Stephen Warren wrote:
> >> However, this results in iterating over table twice; the second time
> >> inside of_match_node(). The implementation of for_each_matching_node()
> >> already found the match, so this is redundant. Invent new function
> >> of_find_matching_node_and_match() and macro
> >> for_each_matching_node_and_match() to remove the double iteration,
> >> thus transforming the above code to:
> >>
> >>     for_each_matching_node_and_match(np, table, &match)
> >>
> >> Signed-off-by: Stephen Warren <swarren@nvidia.com>
> >
> > This look useful, but I wonder if the interface would make more sense if you
> > make the last argument to the macro a normal pointer, rather than a
> > pointer-to-pointer. You can take the reference as part of the macro.
> 
> To me that makes for harder to understand code. It *looks* like an
> argument to a normal function call, but it gets changed by the caller.

Agreed. Too much magic is too much.

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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