From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756231Ab2JJVVB (ORCPT ); Wed, 10 Oct 2012 17:21:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:4678 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755538Ab2JJVU7 (ORCPT ); Wed, 10 Oct 2012 17:20:59 -0400 Date: Wed, 10 Oct 2012 14:20:51 -0700 From: Zach Brown To: "Theodore Ts'o" , Kent Overstreet , linux-bcache@vger.kernel.org, linux-kernel@vger.kernel.org, dm-devel@redhat.com Subject: Re: [PATCH 2/5] aio: kiocb_cancel() Message-ID: <20121010212051.GD6371@lenny.home.zabbo.net> References: <1349764760-21093-1-git-send-email-koverstreet@google.com> <1349764760-21093-2-git-send-email-koverstreet@google.com> <20121009182625.GM26187@lenny.home.zabbo.net> <20121009213700.GF29494@google.com> <20121010110356.GA11468@thunk.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121010110356.GA11468@thunk.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > And maybe the current way of doing things isn't the best way. But it > would be nice if we didn't completely give up on the functionality of > aio_cancel. I sympathize, but the reality is that the current infrastructure is very bad and no one is using it. It's not like we're getting rid of the syscall. I'll be behaving exactly as it does today: returning the error code that indicates that cancellation failed because it lost the race with completion. Every caller has to cope with that to use cancel safely. So if someone eventually implements iocb cancel safely we'll be able to plumb it back under the aio syscalls. But until that day I see no reason to carry around buggy infrastructure that is only slowing down the fast path. - z