linux-kernel - Re: [PATCH 1/9] remove volatile keyword from clflush.

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Message-ID: <4758656B.1000301@goop.org>
Date:	Thu, 06 Dec 2007 13:11:07 -0800
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	Glauber de Oliveira Costa <gcosta@...hat.com>
CC:	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
	glommer@...il.com, tglx@...utronix.de, mingo@...e.hu,
	ehabkost@...hat.com, avi@...ranet.com, anthony@...emonkey.ws,
	virtualization@...ts.linux-foundation.org, rusty@...tcorp.com.au,
	ak@...e.de, chrisw@...s-sol.org, rostedt@...dmis.org, hpa@...or.com
Subject: Re: [PATCH 1/9] remove volatile keyword from clflush.

Glauber de Oliveira Costa wrote:
> the p parameter is an explicit memory reference, and is
> enough to prevent gcc to being nasty here. The volatile
> seems completely not needed.
>   

The usual reason for these types of "volatiles" is to make type checking
happier, since "volatile void *" is compatible with any argument you
might pass.  IOW, if you pass a plain "char *" then the compiler will
promote it to "volatile char *" and not complain, and passing an already
volatile pointer will be OK too.

The volatile isn't there to modify the generated code in any way.

    J
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