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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 9FAD5C352A1 for ; Wed, 7 Dec 2022 06:27:14 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1p2nsd-0000Eo-07; Wed, 07 Dec 2022 01:26:07 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p2nsZ-0000EO-Pp for qemu-devel@nongnu.org; Wed, 07 Dec 2022 01:26:04 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p2nsW-0007oU-Sc for qemu-devel@nongnu.org; Wed, 07 Dec 2022 01:26:02 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1670394354; 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; bh=Jj8Oc0Szx7ALqYTY8A992XdeKUZWjmeL+c28vmxqbSI=; b=houo/a0rgSX7b03HtZRgu3WMsKHIMQu5AtriA0K4tw6HwpMTHosldMCDwHJrwiep3B6w2G KZUjerLPC3rrGNc0+DbQgYxzejQ1redj79JYuMM0Nrcd08NzfABFhVle2DdQVXvoTkh7qF 3+1RGA8Thkn6owB7gkd8UH06e6lgm/U= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-668-MzQrzynTP4ewXlsMpdZrMw-1; Wed, 07 Dec 2022 01:25:53 -0500 X-MC-Unique: MzQrzynTP4ewXlsMpdZrMw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id F2C54811E75 for ; Wed, 7 Dec 2022 06:25:52 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.195.144]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C4BCB1415102; Wed, 7 Dec 2022 06:25:52 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id B0CAD21E6921; Wed, 7 Dec 2022 07:25:49 +0100 (CET) From: Markus Armbruster To: qemu-devel@nongnu.org Cc: "Michael S. Tsirkin" , Marcel Apfelbaum Subject: How to best make include/hw/pci/pcie_sriov.h self-contained Date: Wed, 07 Dec 2022 07:25:49 +0100 Message-ID: <87bkofivbm.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, 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_NONE=-0.0001, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org pcie_sriov.h needs PCI_NUM_REGIONS from pci.h, but doesn't include it. pci.h must be included before pcie_sriov.h or else compile fails. Adding #include "pci/pci.h" to pcie_sriov would be wrong, because it would close an inclusion loop: pci.h includes pcie.h (for PCIExpressDevice) includes pcie_sriov.h (for PCIESriovPF) includes pci.h (for PCI_NUM_REGIONS). The obvious solution is to move PCI_NUM_REGIONS pci.h somewhere pcie_sriov.h can include without creating a loop. We already have a few headers that don't include anything: pci_ids.h, pci_regs.h (includes include/standard-headers/linux/pci_regs.h, which doesn't count), pcie_regs.h. Moving PCI_NUM_REGIONS to one of these would work, but it doesn't feel right. We could create a new one, say pci_defs.h. Just for PCI_NUM_REGIONS feels silly. So, what else should move there? Any other ideas? In case you wonder why I bother you with this... Back in 2016, we discussed[1] rules for headers, and these were generally liked: 1. Have a carefully curated header that's included everywhere first. We got that already thanks to Peter: osdep.h. 2. Headers should normally include everything they need beyond osdep.h. If exceptions are needed for some reason, they must be documented in the header. If all that's needed from a header is typedefs, put those into qemu/typedefs.h instead of including the header. 3. Cyclic inclusion is forbidden. I'm working on patches to get include/ closer to obeying 2. [1] Message-ID: <87h9g8j57d.fsf@blackfin.pond.sub.org> https://lists.nongnu.org/archive/html/qemu-devel/2016-03/msg03345.html