From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1646100-1521559247-2-1730117727406599209 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='de', MailFrom='org' X-Spam-charsets: plain='us-ascii' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: linux-api-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1521559247; b=fgp4v1nrt1ai6QSULQ7s8CiRieSsjpibQ/J6vOHbeFQQ0Ec RMeA2h3N8v5d8F8LQqql+kVyH7lQM3UhJoi4ixUMNC7IO8txUZsjz1Uf9V/YnRIY rCoGYVnaKSU4ygHM4ns9mtlRJcmxh535r099U63GLLiCtztsDOAjdw0nztx8ArN2 iLF3D6Yat2SqS3OLAhr80BZZFSLWYzQJXUDS12txZ1Es8EeOVXwzL4id6/f9CwMj gEDah0x0YBbt/xI01nnk54awfPl1OChA+ZJ/X4COv5EW4w5Te469HCbrFA9cxH6p 6UQGEaNh4sCcexwihhPHon84/kDKBkf8WT4XiNw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=date:from:to:cc:subject:message-id :references:mime-version:content-type:in-reply-to:sender :list-id; s=arctest; t=1521559247; bh=WkCCaOdclLw/zmOslPn0/t6SDr lwrr6vIkWLd3Tc26Y=; b=A8b0IHBUctp0rP+2ANvyex6p1nBFRIWXy1FsBzF59n /BDNvxoRhU16AI0HKmURSB3Yqg1+RdLJYxq3yG+hCutKuBqxtPxp0sPWuRt74gfi LBkkyFSYXiA8qr7av4q9j2MGZdvCg1HznzG1Scz0UkpcoZ32mTZ2QbQv0nVHp8Vs QI6EQdUwtqqtUzKyrkQW3PeAX9j6HbaQI9Z0jU5xHABks8WOSZqtOmLeF7sy1Fpd PfR9me/wfx3SyShx7fNqMI9VAVgF6UpzNAqU675PrCpLNiYXjodn39QiN9orbk3K B4Vv8bvLaMiAe2FTkWgp97TYFOATQaJOjfh4Wck/TuNg== ARC-Authentication-Results: i=1; mx3.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=lst.de; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=lst.de header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx3.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=lst.de; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=lst.de header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751557AbeCTPU1 (ORCPT ); Tue, 20 Mar 2018 11:20:27 -0400 Received: from verein.lst.de ([213.95.11.211]:37717 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751186AbeCTPUZ (ORCPT ); Tue, 20 Mar 2018 11:20:25 -0400 Date: Tue, 20 Mar 2018 16:20:22 +0100 From: Christoph Hellwig To: "Darrick J. Wong" Cc: Christoph Hellwig , viro@zeniv.linux.org.uk, Avi Kivity , linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, netdev@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 07/36] aio: add delayed cancel support Message-ID: <20180320152022.GB23920@lst.de> References: <20180305212743.16664-1-hch@lst.de> <20180305212743.16664-8-hch@lst.de> <20180320031957.GJ7282@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180320031957.GJ7282@magnolia> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-api-owner@vger.kernel.org X-Mailing-List: linux-api@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Mon, Mar 19, 2018 at 08:19:57PM -0700, Darrick J. Wong wrote: > On Mon, Mar 05, 2018 at 01:27:14PM -0800, Christoph Hellwig wrote: > > The upcoming aio poll support would like to be able to complete the > > iocb inline from the cancellation context, but that would cause > > a lock order reversal. Add support for optionally moving the cancelation > > outside the context lock to avoid this reversal. > > I started to wonder which lock order reversal the commit message refers > to? > > I think the reason for adding delayed cancellations is that we want to > be able to call io_cancel -> kiocb_cancel -> aio_poll_cancel -> > aio_complete without double locking ctx_lock? It is. I've updated the commit message.