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Date: Mon, 16 Mar 2015 11:05:31 -0700
From: "H. Peter Anvin" <h.peter.anvin@intel.com>
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To: Ingo Molnar <mingo@kernel.org>,
        Ross Zwisler <ross.zwisler@linux.intel.com>
CC: Borislav Petkov <bp@alien8.de>, linux-kernel@vger.kernel.org,
        Thomas Gleixner <tglx@linutronix.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] x86: Add kerneldoc for pcommit_sfence()
References: <1426097961-24921-1-git-send-email-ross.zwisler@linux.intel.com> <20150311201830.GD3359@pd.tnic> <20150312105843.GA6812@gmail.com> <1426276993.3737.3.camel@theros.lm.intel.com> <20150316083510.GA19634@gmail.com>
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On 03/16/2015 01:35 AM, Ingo Molnar wrote:
> 
> :-/
> 
> Not sure what hpa's problem with 'void *' was: especially in MM code 
> we are using 'void *' rather widely.
> 
> All compilers that aim for being able to build the Linux kernel 
> implement 'void *' as well, so that 'standard C' argument is pretty 
> weak IMHO - unlike some of the more esoteric GCC extensions, this one 
> is actually pretty well done and widely used in and outside of the 
> kernel.
> 
>> It seems like both have arguments for them.  Char pointer arithmetic 
>> has the advantage that its behavior is standard in C, so it's not 
>> specific to gcc.  I agree that void* has the advantage that it fits 
>> more naturally with the types of the parameters passed in, requiring 
>> no casting.
> 
> It's also a bonus property of 'void *' that unlike 'char *' it cannot 
> be dereferenced. So we use it for opaque buffers wherever we can.
> 

The issue isn't void *, it is doing arithmetic on void *.

	-hpa