From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Snook Subject: [PATCH 18/24] make atomic_read() behave consistently on sh Date: Thu, 9 Aug 2007 10:10:34 -0400 Message-ID: <20070809141034.GA18253@shell.boston.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii 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 To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, torvalds@linux-foundation.org Return-path: Received: from mx1.redhat.com ([66.187.233.31]:53749 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934939AbXHIOLI (ORCPT ); Thu, 9 Aug 2007 10:11:08 -0400 Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Chris Snook Purify volatile use for atomic_t on sh. Signed-off-by: Chris Snook --- linux-2.6.23-rc2-orig/include/asm-sh/atomic.h 2007-07-08 19:32:17.000000000 -0400 +++ linux-2.6.23-rc2/include/asm-sh/atomic.h 2007-08-09 07:21:33.000000000 -0400 @@ -7,11 +7,15 @@ * */ -typedef struct { volatile int counter; } atomic_t; +typedef struct { int counter; } atomic_t; #define ATOMIC_INIT(i) ( (atomic_t) { (i) } ) -#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_set(v,i) ((v)->counter = (i)) #include