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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5E20FC433EF for ; Thu, 30 Sep 2021 08:35:33 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 11BE361875 for ; Thu, 30 Sep 2021 08:35:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 11BE361875 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:51124 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mVrXQ-0006dq-5A for qemu-devel@archiver.kernel.org; Thu, 30 Sep 2021 04:35:32 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51292) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mVrWG-0005e4-Rs for qemu-devel@nongnu.org; Thu, 30 Sep 2021 04:34:20 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:60631) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mVrWF-0001sc-8W for qemu-devel@nongnu.org; Thu, 30 Sep 2021 04:34:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1632990858; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=swb1DMITHFf4zyHrhwEsJTEJCCYQl4Di7HZHrWlyDz0=; b=clDW46OIiU1FUNENohuS5iF/vru7lCoM0QzklVvgvay3bL03u0PezeWx2BKlZTun1NBSV7 +vKkE6yEuO7lQEbdJ6+iB9gMijdPJvSrHWMlOjWm1U5go3wa7nkKPhLhEtmboVMvdyL8T8 msr4EvijNqKOOka8vee3uwmCOj0aVw0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-405-2cN7ljbpNqSL_Eoo2c_bUw-1; Thu, 30 Sep 2021 04:34:14 -0400 X-MC-Unique: 2cN7ljbpNqSL_Eoo2c_bUw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BF2FE835DEB for ; Thu, 30 Sep 2021 08:34:13 +0000 (UTC) Received: from redhat.com (unknown [10.39.195.104]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7AE3D60877; Thu, 30 Sep 2021 08:34:12 +0000 (UTC) Date: Thu, 30 Sep 2021 09:34:09 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Leonardo Bras Soares Passos Subject: Re: [PATCH v3 1/3] QIOChannel: Add io_async_writev & io_async_flush callbacks Message-ID: References: <20210922222423.644444-1-leobras@redhat.com> <20210922222423.644444-2-leobras@redhat.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/2.0.7 (2021-05-04) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -8 X-Spam_score: -0.9 X-Spam_bar: / X-Spam_report: (-0.9 / 5.0 requ) DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: qemu-devel , Jason Wang , "Dr. David Alan Gilbert" , Peter Xu , Juan Quintela Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Sep 29, 2021 at 04:06:33PM -0300, Leonardo Bras Soares Passos wrote: > Hello Peter, thanks for reviewing! > > On Tue, Sep 28, 2021 at 6:52 PM Peter Xu wrote: > > > > On Fri, Sep 24, 2021 at 06:16:04PM +0100, Daniel P. Berrangé wrote: > > > > +ssize_t qio_channel_async_writev(QIOChannel *ioc, > > > > + const struct iovec *iov, > > > > + size_t niov, > > > > + int *fds, > > > > + size_t nfds, > > > > + Error **errp); > > > > > > This is missing any flags. We need something like > > > > > > QIO_CHANNEL_WRITE_FLAG_ZEROCOPY > > > > > > passed in an 'unsigned int flags' parameter. This in > > > turn makes me question whether we should have the > > > common helpers at all, as the api is going to be > > > different for sync vs async. > > > > > > The QIOChannelFeature enum probably ought to be > > > extended with QIO_CHANNEL_FEATURE_WRITE_ZEROCOPY with > > > support for probing whether that's supported or not. > > > > I'm also wondering whether we could just drop the fds/nfds as per my knowledge > > SCM_RIGHT is the only user, at the meantime I don't see why an async interface > > would pass in any fd anyways.. Thanks, > > FWIW, I think it's a great idea. > Daniel, what do you think? Yes, FD passing is not compatible with async operations, becuase it is too complex to deal with FD lifetime on failure to send IO Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|