From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932073AbcFOJ2f (ORCPT ); Wed, 15 Jun 2016 05:28:35 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:38473 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751889AbcFOJ2d (ORCPT ); Wed, 15 Jun 2016 05:28:33 -0400 X-IBM-Helo: d23dlp02.au.ibm.com X-IBM-MailFrom: xinhui.pan@linux.vnet.ibm.com X-IBM-RcptTo: linux-arch@vger.kernel.org;linux-kernel@vger.kernel.org Date: Wed, 15 Jun 2016 17:28:17 +0800 From: xinhui User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.8.0 MIME-Version: 1.0 To: Will Deacon CC: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, ingo@redhat.com, peterz@infradead.org, arnd@arndb.de, Waiman.Long@hpe.com Subject: Re: [PATCH] locking/qrwlock: Let qrwlock has same layout regardless of the endian References: <1465982177-2949-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> <20160615092051.GC24029@arm.com> In-Reply-To: <20160615092051.GC24029@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16061509-0008-0000-0000-00000099789D X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16061509-0009-0000-0000-00000777089C Message-Id: <57611FB1.8050205@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-06-15_06:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1606150105 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2016年06月15日 17:20, Will Deacon wrote: > On Wed, Jun 15, 2016 at 05:16:17PM +0800, Pan Xinhui wrote: >> This patch aims to get rid of endianness in queued_write_unlock(). We >> want to set __qrwlock->wmode to NULL, however the address is not >> &lock->cnts in big endian machine. That causes queued_write_unlock() >> write NULL to the wrong field of __qrwlock. >> >> Actually qrwlock can have same layout, IOW we can remove the #if >> __little_endian in struct __qrwlock. With such modification, we only >> need define some _QW* and _QR* with corresponding values in different >> endian systems. >> >> Suggested-by: Will Deacon >> Signed-off-by: Pan Xinhui >> --- >> include/asm-generic/qrwlock.h | 15 +++++++++++---- >> kernel/locking/qrwlock.c | 10 ++++------ >> 2 files changed, 15 insertions(+), 10 deletions(-) >> >> diff --git a/include/asm-generic/qrwlock.h b/include/asm-generic/qrwlock.h >> index 54a8e65..b135c11 100644 >> --- a/include/asm-generic/qrwlock.h >> +++ b/include/asm-generic/qrwlock.h >> @@ -27,11 +27,18 @@ >> /* >> * Writer states & reader shift and bias >> */ >> -#define _QW_WAITING 1 /* A writer is waiting */ >> -#define _QW_LOCKED 0xff /* A writer holds the lock */ >> -#define _QW_WMASK 0xff /* Writer mask */ >> +#ifdef __LITTLE_ENDIAN >> #define _QR_SHIFT 8 /* Reader count shift */ >> -#define _QR_BIAS (1U << _QR_SHIFT) >> +#define _QW_SHIFF 0 /* Writer mode shift */ > > Well, there are other typos that could've been worse, but you probably > want to fix this... > oh... I am really in rush. sorry. will fix it and seed patch v2 soon. thank you for pointing it out. > Will >