From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C2B5FC43387 for ; Fri, 11 Jan 2019 04:25:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 90A312146F for ; Fri, 11 Jan 2019 04:25:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="3p+YzvoL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730745AbfAKEZq (ORCPT ); Thu, 10 Jan 2019 23:25:46 -0500 Received: from userp2130.oracle.com ([156.151.31.86]:45140 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728178AbfAKEZq (ORCPT ); Thu, 10 Jan 2019 23:25:46 -0500 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id x0B4JSSD132505; Fri, 11 Jan 2019 04:25:14 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=IY8sLSOYgVx/ehspVdffeUJz5kK176BpWKLb7Gb8WK8=; b=3p+YzvoL0kYZ22VTCKAtzcOvPcCWa1AF8i6o/mKy3lCv9jJw8TRok8KZ3siyhfk6VO69 rZX4InWXE4q/UvHY/+cqufalksSgkds64+vzPvNcbXHTtztupezvSNWc1vBpjUm+MFiH voZ/DNHbMq2dVsf4Gio22jF+Ay8e9FDvVehLWjn9eZlDaeleofJhBtgfUx9aSqgoFDyh BddQ+Piu2dzsswkn2uznkFzBkpZJ99thwsAyXWEHrAscUkftiQPZhs/Rs2GROUEHrYSs Ipni5h/slAQfai06eDDwNGEAkwrFmuAEQW512K3EdqLSSfosnJGA+iZV5nyBBtDLMoDQ fA== Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by userp2130.oracle.com with ESMTP id 2ptm0ujt7h-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 11 Jan 2019 04:25:13 +0000 Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserv0021.oracle.com (8.14.4/8.14.4) with ESMTP id x0B4PCE8022556 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 11 Jan 2019 04:25:13 GMT Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x0B4PBwc029642; Fri, 11 Jan 2019 04:25:12 GMT Received: from [10.39.212.228] (/10.39.212.228) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 10 Jan 2019 20:25:11 -0800 Subject: Re: [PATCH 3/3] bitops.h: set_mask_bits() to return old value To: Vineet Gupta , linux-kernel@vger.kernel.org Cc: linux-snps-arc@lists.infradead.org, linux-mm@kvack.org, peterz@infradead.org, Miklos Szeredi , Ingo Molnar , Jani Nikula , Chris Wilson , Andrew Morton , Will Deacon References: <1547166387-19785-1-git-send-email-vgupta@synopsys.com> <1547166387-19785-4-git-send-email-vgupta@synopsys.com> From: Anthony Yznaga Organization: Oracle Corporation Message-ID: <693b30a9-96dc-a5e6-9708-c215b90146b0@oracle.com> Date: Thu, 10 Jan 2019 20:25:09 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 MIME-Version: 1.0 In-Reply-To: <1547166387-19785-4-git-send-email-vgupta@synopsys.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9132 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1901110035 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/10/19 4:26 PM, Vineet Gupta wrote: > | > Also, set_mask_bits is used in fs quite a bit and we can possibly come up > | > with a generic llsc based implementation (w/o the cmpxchg loop) > | > | May I also suggest changing the return value of set_mask_bits() to old. > | > | You can compute the new value given old, but you cannot compute the old > | value given new, therefore old is the better return value. Also, no > | current user seems to use the return value, so changing it is without > | risk. > > Link: http://lkml.kernel.org/g/20150807110955.GH16853@twins.programming.kicks-ass.net > Suggested-by: Peter Zijlstra > Cc: Miklos Szeredi > Cc: Ingo Molnar > Cc: Jani Nikula > Cc: Chris Wilson > Cc: Andrew Morton > Cc: Will Deacon > Signed-off-by: Vineet Gupta > Reviewed-by: Anthony Yznaga From mboxrd@z Thu Jan 1 00:00:00 1970 From: anthony.yznaga@oracle.com (Anthony Yznaga) Date: Thu, 10 Jan 2019 20:25:09 -0800 Subject: [PATCH 3/3] bitops.h: set_mask_bits() to return old value In-Reply-To: <1547166387-19785-4-git-send-email-vgupta@synopsys.com> References: <1547166387-19785-1-git-send-email-vgupta@synopsys.com> <1547166387-19785-4-git-send-email-vgupta@synopsys.com> List-ID: Message-ID: <693b30a9-96dc-a5e6-9708-c215b90146b0@oracle.com> To: linux-snps-arc@lists.infradead.org On 1/10/19 4:26 PM, Vineet Gupta wrote: > | > Also, set_mask_bits is used in fs quite a bit and we can possibly come up > | > with a generic llsc based implementation (w/o the cmpxchg loop) > | > | May I also suggest changing the return value of set_mask_bits() to old. > | > | You can compute the new value given old, but you cannot compute the old > | value given new, therefore old is the better return value. Also, no > | current user seems to use the return value, so changing it is without > | risk. > > Link: http://lkml.kernel.org/g/20150807110955.GH16853 at twins.programming.kicks-ass.net > Suggested-by: Peter Zijlstra > Cc: Miklos Szeredi > Cc: Ingo Molnar > Cc: Jani Nikula > Cc: Chris Wilson > Cc: Andrew Morton > Cc: Will Deacon > Signed-off-by: Vineet Gupta > Reviewed-by: Anthony Yznaga