From patchwork Mon Sep 22 21:50:42 2008 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 970 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id EE81BDDE08 for ; Tue, 23 Sep 2008 07:57:50 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753924AbYIVV5m (ORCPT ); Mon, 22 Sep 2008 17:57:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753800AbYIVV5l (ORCPT ); Mon, 22 Sep 2008 17:57:41 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:58971 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753919AbYIVV5j (ORCPT ); Mon, 22 Sep 2008 17:57:39 -0400 Received: from imap1.linux-foundation.org (imap1.linux-foundation.org [140.211.169.55]) by smtp1.linux-foundation.org (8.14.2/8.13.5/Debian-3ubuntu1.1) with ESMTP id m8MLrDOF018507 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 22 Sep 2008 14:57:34 -0700 Received: from localhost.localdomain (localhost [127.0.0.1]) by imap1.linux-foundation.org (8.13.5.20060308/8.13.5/Debian-3ubuntu1.1) with ESMTP id m8MLog27031875; Mon, 22 Sep 2008 14:50:43 -0700 Message-Id: <200809222150.m8MLog27031875@imap1.linux-foundation.org> Subject: [patch 7/8] hci_usb: replace mb with smp_mb To: davem@davemloft.net Cc: netdev@vger.kernel.org, akpm@linux-foundation.org, tom.leiming@gmail.com, hidave.darkstar@gmail.com, marcel@holtmann.org From: akpm@linux-foundation.org Date: Mon, 22 Sep 2008 14:50:42 -0700 X-Spam-Status: No, hits=-3.359 required=5 tests=AWL, BAYES_00, OSDL_HEADER_SUBJECT_BRACKETED X-Spam-Checker-Version: SpamAssassin 3.2.4-osdl_revision__1.47__ X-MIMEDefang-Filter: lf$Revision: 1.188 $ X-Scanned-By: MIMEDefang 2.63 on 140.211.169.13 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Ming Lei smp_mb is enough for ordering memory operations among processors,and mb is more expensive than smp_mb for UP machine, so replace it with smp_mb(). Signed-off-by: Ming Lei Acked-by: Marcel Holtmann Cc: Dave Young Signed-off-by: Andrew Morton --- drivers/bluetooth/hci_usb.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff -puN drivers/bluetooth/hci_usb.h~hci_usb-replace-mb-with-smp_mb drivers/bluetooth/hci_usb.h --- a/drivers/bluetooth/hci_usb.h~hci_usb-replace-mb-with-smp_mb +++ a/drivers/bluetooth/hci_usb.h @@ -70,8 +70,8 @@ static inline void _urb_queue_head(struc { unsigned long flags; spin_lock_irqsave(&q->lock, flags); - /* _urb_unlink needs to know which spinlock to use, thus mb(). */ - _urb->queue = q; mb(); list_add(&_urb->list, &q->head); + /* _urb_unlink needs to know which spinlock to use, thus smp_mb(). */ + _urb->queue = q; smp_mb(); list_add(&_urb->list, &q->head); spin_unlock_irqrestore(&q->lock, flags); } @@ -79,8 +79,8 @@ static inline void _urb_queue_tail(struc { unsigned long flags; spin_lock_irqsave(&q->lock, flags); - /* _urb_unlink needs to know which spinlock to use, thus mb(). */ - _urb->queue = q; mb(); list_add_tail(&_urb->list, &q->head); + /* _urb_unlink needs to know which spinlock to use, thus smp_mb(). */ + _urb->queue = q; smp_mb(); list_add_tail(&_urb->list, &q->head); spin_unlock_irqrestore(&q->lock, flags); } @@ -89,7 +89,7 @@ static inline void _urb_unlink(struct _u struct _urb_queue *q; unsigned long flags; - mb(); + smp_mb(); q = _urb->queue; /* If q is NULL, it will die at easy-to-debug NULL pointer dereference. No need to BUG(). */