From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-out.m-online.net (mail-out.m-online.net [212.18.0.9]) by sourceware.org (Postfix) with ESMTPS id E8A7F395253D for ; Thu, 19 May 2022 15:25:25 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org E8A7F395253D Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=linux-m68k.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=nefkom.net Received: from frontend01.mail.m-online.net (unknown [192.168.8.182]) by mail-out.m-online.net (Postfix) with ESMTP id 4L3tw43qpvz1qyJB; Thu, 19 May 2022 17:25:24 +0200 (CEST) Received: from localhost (dynscan1.mnet-online.de [192.168.6.70]) by mail.m-online.net (Postfix) with ESMTP id 4L3tw42Sh7z1qqkB; Thu, 19 May 2022 17:25:24 +0200 (CEST) X-Virus-Scanned: amavisd-new at mnet-online.de Received: from mail.mnet-online.de ([192.168.8.182]) by localhost (dynscan1.mail.m-online.net [192.168.6.70]) (amavisd-new, port 10024) with ESMTP id YX7RcAszleho; Thu, 19 May 2022 17:25:23 +0200 (CEST) X-Auth-Info: JZwyQKTmjvfsu45U3gKlOVcvsv4qKx6mwCt81n9gJXx8KsySQQ5S3eounxsCWdXU Received: from igel.home (ppp-46-244-179-69.dynamic.mnet-online.de [46.244.179.69]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.mnet-online.de (Postfix) with ESMTPSA; Thu, 19 May 2022 17:25:23 +0200 (CEST) Received: by igel.home (Postfix, from userid 1000) id 23E782C3A89; Thu, 19 May 2022 17:25:23 +0200 (CEST) From: Andreas Schwab To: Wilco Dijkstra via Libc-alpha Cc: Wilco Dijkstra Subject: Re: [PATCH] Avoid RMW of flags2 outside lock (BZ #27842) References: X-Yow: I want to read my new poem about pork brains and outer space... Date: Thu, 19 May 2022 17:25:23 +0200 In-Reply-To: (Wilco Dijkstra via Libc-alpha's message of "Thu, 19 May 2022 15:10:22 +0000") Message-ID: <871qwpwnmk.fsf@igel.home> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, KAM_DMARC_STATUS, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 19 May 2022 15:25:27 -0000 On Mai 19 2022, Wilco Dijkstra via Libc-alpha wrote: > Remove an unconditional RMW on flags2 in flockfile - if _IO_FLAGS2_NEED_LOCK > is set, we are single-threaded and we can safely clear the flag. Isn't that backwards? In single-theaded case, the flags is normally not set, and it can safely be set. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."