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=-8.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 C49A3C4363D for ; Thu, 24 Sep 2020 19:18:30 +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 F12D121D91 for ; Thu, 24 Sep 2020 19:18:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="dUmnD0d8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F12D121D91 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:41884 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kLWl9-0001vX-Sa for qemu-devel@archiver.kernel.org; Thu, 24 Sep 2020 15:18:27 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47428) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kLWdk-0005Ds-1i for qemu-devel@nongnu.org; Thu, 24 Sep 2020 15:10:49 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:53490) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kLWdg-0004bB-2V for qemu-devel@nongnu.org; Thu, 24 Sep 2020 15:10:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600974642; h=from:from: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=4z0A7EMcviNKUGxP8mlTfQPnRBVv33kdl1gcD44oSc8=; b=dUmnD0d8aLPiuHANKrkMwIE4J8HN49itZQ/abMztBYMnorRaCvG8yt0q30SrSMXN8tvZ+9 CEa8pJa9P/zkDh4x2s+6ZBTiDkaNdiWAvBXyxpfQz8GlvxGcXWNn27LFLhnsBlXj4TMPmY VxLDMerqPxlPVtQzRs4WEQUNxSuVhWg= 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-594-UM5rInt_M6aY6GY_e783Ng-1; Thu, 24 Sep 2020 15:10:35 -0400 X-MC-Unique: UM5rInt_M6aY6GY_e783Ng-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8C9CD807356; Thu, 24 Sep 2020 19:10:34 +0000 (UTC) Received: from [10.3.114.148] (ovpn-114-148.phx2.redhat.com [10.3.114.148]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CD06B5C1C7; Thu, 24 Sep 2020 19:10:30 +0000 (UTC) Subject: Re: [PATCH v9 4/7] scripts: add block-coroutine-wrapper.py To: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org References: <20200924185414.28642-1-vsementsov@virtuozzo.com> <20200924185414.28642-5-vsementsov@virtuozzo.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: <20235fa1-b269-7f49-0a0b-9f7c6f06eca8@redhat.com> Date: Thu, 24 Sep 2020 14:10:30 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200924185414.28642-5-vsementsov@virtuozzo.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eblake@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=63.128.21.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/24 01:10:00 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.199, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.214, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=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: , Cc: fam@euphon.net, kwolf@redhat.com, ehabkost@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com, stefanha@redhat.com, crosa@redhat.com, den@openvz.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 9/24/20 1:54 PM, Vladimir Sementsov-Ogievskiy wrote: > We have a very frequent pattern of creating a coroutine from a function > with several arguments: > > - create a structure to pack parameters > - create _entry function to call original function taking parameters > from struct > - do different magic to handle completion: set ret to NOT_DONE or > EINPROGRESS or use separate bool field > - fill the struct and create coroutine from _entry function with this > struct as a parameter > - do coroutine enter and BDRV_POLL_WHILE loop > > Let's reduce code duplication by generating coroutine wrappers. > > This patch adds scripts/block-coroutine-wrapper.py together with some > friends, which will generate functions with declared prototypes marked > by the 'generated_co_wrapper' specifier. > > The usage of new code generation is as follows: > > 1. define the coroutine function somewhere > > int coroutine_fn bdrv_co_NAME(...) {...} > > 2. declare in some header file > > int generated_co_wrapper bdrv_NAME(...); > > with same list of parameters (generated_co_wrapper is > defined in "include/block/block.h"). > > 3. Make sure the block_gen_c delaration in block/meson.build declaration > mentions the file with your marker function. > > Still, no function is now marked, this work is for the following > commit. > > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > +++ b/docs/devel/block-coroutine-wrapper.rst > @@ -0,0 +1,54 @@ > +======================= > +block-coroutine-wrapper > +======================= > + > +A lot of functions in QEMU block layer (see ``block/*``) can only be > +called in coroutine context. Such functions are normally marked by the > +coroutine_fn specifier. Still, sometimes we need to call them from > +non-coroutine context; for this we need to start a coroutine, run the > +needed function from it and wait for coroutine finish in to finish in a > +BDRV_POLL_WHILE() loop. To run a coroutine we need a function with one > +void* argument. So for each coroutine_fn function which needs a > +non-coroutine interface, we should define a structure to pack the > +parameters, define a separate function to unpack the parameters and > +call the original function and finally define a new interface function > +with same list of arguments as original one, which will pack the > +parameters into a struct, create a coroutine, run it and wait in > +BDRV_POLL_WHILE() loop. It's boring to create such wrappers by hand, > +so we have a script to generate them. > + > +++ b/scripts/block-coroutine-wrapper.py Reviewed-by: Eric Blake -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org