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,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 76C92C433E0 for ; Thu, 6 Aug 2020 11:57:45 +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 3F5AB22D00 for ; Thu, 6 Aug 2020 11:57:45 +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="Lf6FZGc2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3F5AB22D00 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]:34288 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k3bRs-0005u1-Q3 for qemu-devel@archiver.kernel.org; Thu, 06 Aug 2020 04:40:28 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:40168) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k3bR9-0005QQ-QS for qemu-devel@nongnu.org; Thu, 06 Aug 2020 04:39:43 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:41946 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1k3bR7-0000s0-DT for qemu-devel@nongnu.org; Thu, 06 Aug 2020 04:39:43 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1596703179; 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:in-reply-to:in-reply-to: references:references; bh=GqG+JA+Gqx9K0v+2iqLpk3uvYM5+OokXWP84pT375gs=; b=Lf6FZGc24Ch3NferHyjysguu1eKMB6xZ2Eh1JRZObNLVSGfr+wSJpEoxoQPP3vU9d4hww4 yFiCf+mMk8Hai3vV642JCB89Q6KffIPAdSg2gKmn4DvO7vgQTFr5WYqeguvLnXHXAHmu26 o/gh4mnqicfURotLD5d2RL2lxOgzecI= 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-186-ROiBYr-_PuuuMbqfiG5i7w-1; Thu, 06 Aug 2020 04:38:50 -0400 X-MC-Unique: ROiBYr-_PuuuMbqfiG5i7w-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1F4F7102C7ED; Thu, 6 Aug 2020 08:38:49 +0000 (UTC) Received: from redhat.com (unknown [10.36.110.44]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2B7C25DA6A; Thu, 6 Aug 2020 08:38:43 +0000 (UTC) Date: Thu, 6 Aug 2020 09:38:41 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Markus Armbruster Subject: Re: [PATCH] ide: Get rid of IDEDrive struct Message-ID: <20200806083841.GA4159383@redhat.com> References: <20200805194812.1735218-1-ehabkost@redhat.com> <20200805221417.GC1700540@habkost.net> <877ducb9jl.fsf@dusky.pond.sub.org> MIME-Version: 1.0 In-Reply-To: <877ducb9jl.fsf@dusky.pond.sub.org> User-Agent: Mutt/1.14.5 (2020-06-23) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 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 Received-SPF: pass client-ip=205.139.110.120; envelope-from=berrange@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/06 00:24:10 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=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: Peter Maydell , Eduardo Habkost , Qemu-block , QEMU Developers , Gerd Hoffmann , John Snow Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Aug 06, 2020 at 07:58:06AM +0200, Markus Armbruster wrote: > Eduardo Habkost writes: > > > On Wed, Aug 05, 2020 at 09:41:25PM +0100, Peter Maydell wrote: > >> On Wed, 5 Aug 2020 at 20:49, Eduardo Habkost wrote: > >> > > >> > The struct had a single field (IDEDevice dev), and is only used > >> > in the QOM type declarations and property lists. We can simply > >> > use the IDEDevice struct directly instead. > >> > > >> > Signed-off-by: Eduardo Habkost > >> > @@ -327,7 +323,6 @@ static void ide_hd_class_init(ObjectClass *klass, void *data) > >> > static const TypeInfo ide_hd_info = { > >> > .name = "ide-hd", > >> > .parent = TYPE_IDE_DEVICE, > >> > - .instance_size = sizeof(IDEDrive), > >> > .class_init = ide_hd_class_init, > >> > }; > >> > >> This is one of those areas where this change works and reduces > >> amount of code, but on the other hand it means the QOM type > >> doesn't follow the common pattern for a leaf type of: > >> * it has a struct > >> * it has cast macros that cast to that struct > >> * the typeinfo instance_size is the size of that struct > >> (it wasn't exactly following this pattern before, of course). > > > > Is this really a pattern that exists and we want to follow? > > I don't see why that pattern would be useful for simple leaf > > types. > > I think the pattern exists, but we deviate from it in quite a few > places, probably just because it's so much boilerplate. > > Related: Daniel's "[PATCH 0/4] qom: reduce boilerplate required for > declaring and defining objects". Perhaps Daniel has an opinion on > taking shortcuts with leaf types. I think following a consistent pattern everywhere is important, because people look at existing code to guide their new code. The boilerplate pain is very real, but I think my patch series you point to will reduce the burden sufficiently that the kind of optimization proposed here is not required. 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 :|