Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S939606AbXHIOCp (ORCPT ); Thu, 9 Aug 2007 10:02:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S935256AbXHIOCd (ORCPT ); Thu, 9 Aug 2007 10:02:33 -0400 Received: from mx1.redhat.com ([66.187.233.31]:50451 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933695AbXHIOCb (ORCPT ); Thu, 9 Aug 2007 10:02:31 -0400 Date: Thu, 9 Aug 2007 10:01:54 -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 14/24] make atomic_read() behave consistently on parisc Message-ID: <20070809140154.GA17489@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 Content-Length: 1809 Lines: 55 From: Chris Snook Purify volatile use for atomic[64]_t on parisc. Signed-off-by: Chris Snook --- linux-2.6.23-rc2-orig/include/asm-parisc/atomic.h 2007-07-08 19:32:17.000000000 -0400 +++ linux-2.6.23-rc2/include/asm-parisc/atomic.h 2007-08-09 07:11:38.000000000 -0400 @@ -128,7 +128,7 @@ __cmpxchg(volatile void *ptr, unsigned l * Cache-line alignment would conflict with, for example, linux/module.h */ -typedef struct { volatile int counter; } atomic_t; +typedef struct { int counter; } atomic_t; /* It's possible to reduce all atomic operations to either * __atomic_add_return, atomic_set and atomic_read (the latter @@ -157,9 +157,13 @@ static __inline__ void atomic_set(atomic _atomic_spin_unlock_irqrestore(v, flags); } +/* + * Casting to volatile here minimizes the need for barriers, + * without having to declare the type itself as volatile. + */ static __inline__ int atomic_read(const atomic_t *v) { - return v->counter; + return (*(volatile int *)&(v)->counter); } /* exported interface */ @@ -227,7 +231,7 @@ static __inline__ int atomic_add_unless( #ifdef CONFIG_64BIT -typedef struct { volatile s64 counter; } atomic64_t; +typedef struct { s64 counter; } atomic64_t; #define ATOMIC64_INIT(i) ((atomic64_t) { (i) }) @@ -258,7 +262,7 @@ atomic64_set(atomic64_t *v, s64 i) static __inline__ s64 atomic64_read(const atomic64_t *v) { - return v->counter; + return (*(volatile s64 *)&(v)->counter); } #define atomic64_add(i,v) ((void)(__atomic64_add_return( ((s64)i),(v)))) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/