From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755473AbYHDNiU (ORCPT ); Mon, 4 Aug 2008 09:38:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752460AbYHDNiM (ORCPT ); Mon, 4 Aug 2008 09:38:12 -0400 Received: from vpn.id2.novell.com ([195.33.99.129]:19209 "EHLO vpn.id2.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752190AbYHDNiM convert rfc822-to-8bit (ORCPT ); Mon, 4 Aug 2008 09:38:12 -0400 Message-Id: <4897228E.76E4.0078.0@novell.com> X-Mailer: Novell GroupWise Internet Agent 7.0.3 Date: Mon, 04 Aug 2008 14:38:54 +0100 From: "Jan Beulich" To: , , Cc: "Nick Piggin" , Subject: [PATCH] x86: fix spin_is_contended() Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The masked difference is what needs to be compared against 1, rather than the difference of masked values (which can be negative). Signed-off-by: Jan Beulich Cc: Nick Piggin --- include/asm-x86/spinlock.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- linux-2.6.27-rc1/include/asm-x86/spinlock.h 2008-07-31 17:08:34.000000000 +0200 +++ 2.6.27-rc1-x86-spin-is-contended/include/asm-x86/spinlock.h 2008-08-04 11:09:33.000000000 +0200 @@ -65,7 +65,7 @@ static inline int __ticket_spin_is_conte { int tmp = ACCESS_ONCE(lock->slock); - return (((tmp >> 8) & 0xff) - (tmp & 0xff)) > 1; + return (((tmp >> 8) - tmp) & 0xff) > 1; } static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock) @@ -127,7 +127,7 @@ static inline int __ticket_spin_is_conte { int tmp = ACCESS_ONCE(lock->slock); - return (((tmp >> 16) & 0xffff) - (tmp & 0xffff)) > 1; + return (((tmp >> 16) - tmp) & 0xffff) > 1; } static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock)