From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S940453AbXHIOP0 (ORCPT ); Thu, 9 Aug 2007 10:15:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S936423AbXHIOPH (ORCPT ); Thu, 9 Aug 2007 10:15:07 -0400 Received: from mx1.redhat.com ([66.187.233.31]:54837 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935516AbXHIOPE (ORCPT ); Thu, 9 Aug 2007 10:15:04 -0400 Date: Thu, 9 Aug 2007 10:14:47 -0400 From: Chris Snook To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, torvalds@linux-foundation.org Cc: netdev@vger.kernel.org, akpm@linux-foundation.org, ak@suse.de, heiko.carstens@de.ibm.com, davem@davemloft.net, schwidefsky@de.ibm.com, wensong@linux-vs.org, horms@verge.net.au, wjiang@resilience.com, cfriesen@nortel.com, zlynx@acm.org, rpjday@mindspring.com, jesper.juhl@gmail.com Subject: [PATCH 20/24] make atomic_read() behave consistently on sparc Message-ID: <20070809141447.GA18787@shell.boston.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Chris Snook Purify volatile use for atomic_t on sparc. Leave atomic24_t alone, since it's only used by sparc-specific code. Signed-off-by: Chris Snook --- linux-2.6.23-rc2-orig/include/asm-sparc/atomic.h 2007-07-08 19:32:17.000000000 -0400 +++ linux-2.6.23-rc2/include/asm-sparc/atomic.h 2007-08-09 07:29:31.000000000 -0400 @@ -13,7 +13,7 @@ #include -typedef struct { volatile int counter; } atomic_t; +typedef struct { int counter; } atomic_t; #ifdef __KERNEL__ @@ -61,7 +61,11 @@ extern int atomic_cmpxchg(atomic_t *, in extern int atomic_add_unless(atomic_t *, int, int); extern void atomic_set(atomic_t *, int); -#define atomic_read(v) ((v)->counter) +/* + * Casting to volatile here minimizes the need for barriers, + * without having to declare the type itself as volatile. + */ +#define atomic_read(v) (*(volatile int *)&(v)->counter) #define atomic_add(i, v) ((void)__atomic_add_return( (int)(i), (v))) #define atomic_sub(i, v) ((void)__atomic_add_return(-(int)(i), (v)))