Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751179AbWCaB3O (ORCPT ); Thu, 30 Mar 2006 20:29:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751178AbWCaB3O (ORCPT ); Thu, 30 Mar 2006 20:29:14 -0500 Received: from mga01.intel.com ([192.55.52.88]:15024 "EHLO fmsmga101-1.fm.intel.com") by vger.kernel.org with ESMTP id S1751108AbWCaB3N (ORCPT ); Thu, 30 Mar 2006 20:29:13 -0500 X-IronPort-AV: i="4.03,148,1141632000"; d="scan'208"; a="17991384:sNHT176792217" Message-Id: <200603310129.k2V1TCg27391@unix-os.sc.intel.com> From: "Chen, Kenneth W" To: "'Christoph Lameter'" Cc: "Nick Piggin" , "Zoltan Menyhart" , "Boehm, Hans" , "Grundler, Grant G" , , , Subject: RE: Synchronizing Bit operations V2 Date: Thu, 30 Mar 2006 17:29:56 -0800 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook, Build 11.0.6353 Thread-Index: AcZUYEhkCViVzmVURkezJv7VEOB0fAAAc8cA In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 916 Lines: 27 Christoph Lameter wrote on Thursday, March 30, 2006 5:13 PM > Then there will no barrier since clear_bit only has acquire semantics. > This is a bug in bit operations since smb_mb__before_clear_bit does > not work as documentted. Well, please make up your mind with: Option (1): #define clear_bit clear_bit_mode(..., RELEASE) #define Smp_mb__before_clear_bit do { } while (0) #define Smp_mb__after_clear_bit smp_mb() Or option (2): #define clear_bit clear_bit_mode(..., ACQUIRE) #define Smp_mb__before_clear_bit smp_mb() #define Smp_mb__after_clear_bit do { } while (0) I'm fine with either one. - Ken - 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/