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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7D43FC54798 for ; Fri, 23 Feb 2024 18:49:16 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rdab0-00037O-3M; Fri, 23 Feb 2024 13:48:31 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rdaD3-0000Dd-2k for qemu-devel@nongnu.org; Fri, 23 Feb 2024 13:23:45 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rdaD0-0002XV-8c for qemu-devel@nongnu.org; Fri, 23 Feb 2024 13:23:44 -0500 Received: from mail.maildlp.com (unknown [172.18.186.231]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4ThJDs3f70z67M1h; Sat, 24 Feb 2024 02:19:09 +0800 (CST) Received: from lhrpeml500005.china.huawei.com (unknown [7.191.163.240]) by mail.maildlp.com (Postfix) with ESMTPS id 9900A14058E; Sat, 24 Feb 2024 02:23:35 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.35; Fri, 23 Feb 2024 18:23:35 +0000 Date: Fri, 23 Feb 2024 18:23:34 +0000 To: Richard Henderson CC: Peter Maydell , Subject: Re: [PATCH] atomic.h: Reword confusing comment for qatomic_cmpxchg Message-ID: <20240223182334.000014ca@Huawei.com> In-Reply-To: <808e13f8-11da-4ec1-969d-d2495cbd3a88@linaro.org> References: <20240223182035.1048541-1-peter.maydell@linaro.org> <808e13f8-11da-4ec1-969d-d2495cbd3a88@linaro.org> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml100003.china.huawei.com (7.191.160.210) To lhrpeml500005.china.huawei.com (7.191.163.240) Received-SPF: pass client-ip=185.176.79.56; envelope-from=jonathan.cameron@huawei.com; helo=frasgout.his.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-to: Jonathan Cameron From: Jonathan Cameron via Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Fri, 23 Feb 2024 08:21:42 -1000 Richard Henderson wrote: > On 2/23/24 08:20, Peter Maydell wrote: > > The qatomic_cmpxchg() and qatomic_cmpxchg__nocheck() macros have > > a comment that reads: > > Returns the eventual value, failed or not > > > > This is somewhere between cryptic and wrong, since the value actually > > returned is the value that was in memory before the cmpxchg. Reword > > to match how we describe these macros in atomics.rst. > > > > Signed-off-by: Peter Maydell > > --- > > include/qemu/atomic.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h > > index f1d3d1702a9..99110abefb3 100644 > > --- a/include/qemu/atomic.h > > +++ b/include/qemu/atomic.h > > @@ -202,7 +202,7 @@ > > qatomic_xchg__nocheck(ptr, i); \ > > }) > > > > -/* Returns the eventual value, failed or not */ > > +/* Returns the old value of '*ptr' (whether the cmpxchg failed or not) */ > > #define qatomic_cmpxchg__nocheck(ptr, old, new) ({ \ > > typeof_strip_qual(*ptr) _old = (old); \ > > (void)__atomic_compare_exchange_n(ptr, &_old, new, false, \ > > Reviewed-by: Richard Henderson Reviewed-by: Jonathan Cameron As the person it confused ;) > > r~