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=-2.4 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT 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 700B5C43142 for ; Tue, 31 Jul 2018 08:53:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BBC8520870 for ; Tue, 31 Jul 2018 08:53:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="fG1BWqbh" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BBC8520870 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729782AbeGaKc2 (ORCPT ); Tue, 31 Jul 2018 06:32:28 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:48646 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727608AbeGaKc2 (ORCPT ); Tue, 31 Jul 2018 06:32:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=+d6dxIydmDGzGUcHW51+EdQ0pZRUvIfZR3rUqB2lB8g=; b=fG1BWqbh1pjNSkAW4EOvObe2Y migJeLN+9BpOxvO7PNGGjbsagFm5XaquhA222qvdvQW6CfT8laGd4eeiqlaUYnxYzYLzbvBj/GDYu 03QYzKUKMZrRVOtbJnUCOBKbU6e1UY/ubPhD8qsfiklV3zTFRN3fvgswj6YMjj12lpvYRNH7T+7FP RCdWmmXIZAlpziWcVh40Z7mWxx23Tfe+WVefh/JDnnceansuxQCkeXuMc89vAQTqbUmPB/qj/vTqa i7xLxEMml+rlLLGSTIdbc0dHroPScr5+jkN3MudQ2LrJy+LW3LTG2V59e7EVdpWdAEtbM4a1hWYBL NXwlLPWAg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fkQOp-0007J1-VQ; Tue, 31 Jul 2018 08:53:00 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id D40552027585B; Tue, 31 Jul 2018 10:52:57 +0200 (CEST) Date: Tue, 31 Jul 2018 10:52:57 +0200 From: Peter Zijlstra To: Byungchul Park Cc: linux-kernel@vger.kernel.org, kernel-team@lge.com, ying.huang@intel.com, mingo@kernel.org, jiangshanlai@gmail.com, paulmck@linux.vnet.ibm.com, josh@joshtriplett.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, joel@joelfernandes.org, len.brown@intel.com, glider@google.com, peter@hurleysoftware.com, aik@ozlabs.ru Subject: Re: [QUESTION] llist: Comment releasing 'must delete' restriction before traversing Message-ID: <20180731085257.GR2494@hirez.programming.kicks-ass.net> References: <1532998716-5037-1-git-send-email-byungchul.park@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1532998716-5037-1-git-send-email-byungchul.park@lge.com> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 31, 2018 at 09:58:36AM +0900, Byungchul Park wrote: > In restrictive cases like only addtions happen but never deletion, can't > we safely traverse a llist? I believe llist can be more useful if we can > release the restriction. Can't we? Yes you can, but I'm not sure it makes much sense to confuse the comments with this. This really ends up in the 'you had better know what you're doing' category.