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 CFE12C4332F for ; Wed, 9 Nov 2022 12:30:01 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oskCy-0005LQ-5I; Wed, 09 Nov 2022 07:29:32 -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 1oskCw-0005Kk-CH for qemu-devel@nongnu.org; Wed, 09 Nov 2022 07:29:30 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oskCu-0008Sp-Ko for qemu-devel@nongnu.org; Wed, 09 Nov 2022 07:29:30 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667996968; 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: in-reply-to:in-reply-to:references:references; bh=oIfbGEpMn3ZxHXULHbON+b9cK8EcMQ0TguPrHQLFt7k=; b=Z3LNx3ciSEq+6wwAjPeZqQEiPm+cAGud8QKXNkIE+ZbsDtWI2sWTpI0LDYhqk01hC/BYET YJA83i56SiJaf9a0BBT5/4VKGvLieCdlPaCfdiYpL6UobP3ArSesaom+Wou/u1TQaRwLVg 4pgqF1w+A83Gmr9ZegQSBGNAHRuh7BQ= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-373-MRJibsNKN8y70_Yxeg-aVg-1; Wed, 09 Nov 2022 07:29:24 -0500 X-MC-Unique: MRJibsNKN8y70_Yxeg-aVg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4617F380671D; Wed, 9 Nov 2022 12:29:24 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.193.175]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CC37EC16922; Wed, 9 Nov 2022 12:29:23 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id C16CD21E6921; Wed, 9 Nov 2022 13:29:20 +0100 (CET) From: Markus Armbruster To: Klaus Jensen Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, Keith Busch , Klaus Jensen Subject: Re: [PATCH 1/2] hw/nvme: fix incorrect use of errp/local_err References: <20221109105357.30430-1-its@irrelevant.dk> <20221109105357.30430-2-its@irrelevant.dk> Date: Wed, 09 Nov 2022 13:29:20 +0100 In-Reply-To: <20221109105357.30430-2-its@irrelevant.dk> (Klaus Jensen's message of "Wed, 9 Nov 2022 11:53:56 +0100") Message-ID: <87wn84nwf3.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 10.11.54.8 Received-SPF: pass client-ip=170.10.129.124; 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 Klaus Jensen writes: > From: Klaus Jensen > > Make nvme_check_constraints() return an int and fix incorrect use of > errp/local_err. > > Signed-off-by: Klaus Jensen > --- > hw/nvme/ctrl.c | 48 +++++++++++++++++++++++------------------------- > 1 file changed, 23 insertions(+), 25 deletions(-) > > diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c > index ac3885ce5079..4cc6ae753295 100644 > --- a/hw/nvme/ctrl.c > +++ b/hw/nvme/ctrl.c > @@ -7035,7 +7035,7 @@ static const MemoryRegionOps nvme_cmb_ops = { > }, > }; > > -static void nvme_check_constraints(NvmeCtrl *n, Error **errp) > +static int nvme_check_params(NvmeCtrl *n, Error **errp) I prefer bool true on success, false on failure. I use int only when it lets me return additional information, such as a non-negative value on success, or a negative error code on failure. nvme_init_pci() is an example of the latter (although its caller doesn't care). Local consistency with nvme_init_subsys() is desirable. You could convert it to bool, along with nvme_init_pci(). Or you keep all three int. Up to you. > { > NvmeParams *params = &n->params; > > @@ -7049,38 +7049,38 @@ static void nvme_check_constraints(NvmeCtrl *n, Error **errp) > if (n->namespace.blkconf.blk && n->subsys) { > error_setg(errp, "subsystem support is unavailable with legacy " > "namespace ('drive' property)"); > - return; > + return -1; > } > > if (params->max_ioqpairs < 1 || > params->max_ioqpairs > NVME_MAX_IOQPAIRS) { > error_setg(errp, "max_ioqpairs must be between 1 and %d", > NVME_MAX_IOQPAIRS); > - return; > + return -1; > } > > if (params->msix_qsize < 1 || > params->msix_qsize > PCI_MSIX_FLAGS_QSIZE + 1) { > error_setg(errp, "msix_qsize must be between 1 and %d", > PCI_MSIX_FLAGS_QSIZE + 1); > - return; > + return -1; > } > > if (!params->serial) { > error_setg(errp, "serial property not set"); > - return; > + return -1; > } > > if (n->pmr.dev) { > if (host_memory_backend_is_mapped(n->pmr.dev)) { > error_setg(errp, "can't use already busy memdev: %s", > object_get_canonical_path_component(OBJECT(n->pmr.dev))); > - return; > + return -1; > } > > if (!is_power_of_2(n->pmr.dev->size)) { > error_setg(errp, "pmr backend size needs to be power of 2 in size"); > - return; > + return -1; > } > > host_memory_backend_set_mapped(n->pmr.dev, true); > @@ -7089,64 +7089,64 @@ static void nvme_check_constraints(NvmeCtrl *n, Error **errp) > if (n->params.zasl > n->params.mdts) { > error_setg(errp, "zoned.zasl (Zone Append Size Limit) must be less " > "than or equal to mdts (Maximum Data Transfer Size)"); > - return; > + return -1; > } > > if (!n->params.vsl) { > error_setg(errp, "vsl must be non-zero"); > - return; > + return -1; > } > > if (params->sriov_max_vfs) { > if (!n->subsys) { > error_setg(errp, "subsystem is required for the use of SR-IOV"); > - return; > + return -1; > } > > if (params->sriov_max_vfs > NVME_MAX_VFS) { > error_setg(errp, "sriov_max_vfs must be between 0 and %d", > NVME_MAX_VFS); > - return; > + return -1; > } > > if (params->cmb_size_mb) { > error_setg(errp, "CMB is not supported with SR-IOV"); > - return; > + return -1; > } > > if (n->pmr.dev) { > error_setg(errp, "PMR is not supported with SR-IOV"); > - return; > + return -1; > } > > if (!params->sriov_vq_flexible || !params->sriov_vi_flexible) { > error_setg(errp, "both sriov_vq_flexible and sriov_vi_flexible" > " must be set for the use of SR-IOV"); > - return; > + return -1; > } > > if (params->sriov_vq_flexible < params->sriov_max_vfs * 2) { > error_setg(errp, "sriov_vq_flexible must be greater than or equal" > " to %d (sriov_max_vfs * 2)", params->sriov_max_vfs * 2); > - return; > + return -1; > } > > if (params->max_ioqpairs < params->sriov_vq_flexible + 2) { > error_setg(errp, "(max_ioqpairs - sriov_vq_flexible) must be" > " greater than or equal to 2"); > - return; > + return -1; > } > > if (params->sriov_vi_flexible < params->sriov_max_vfs) { > error_setg(errp, "sriov_vi_flexible must be greater than or equal" > " to %d (sriov_max_vfs)", params->sriov_max_vfs); > - return; > + return -1; > } > > if (params->msix_qsize < params->sriov_vi_flexible + 1) { > error_setg(errp, "(msix_qsize - sriov_vi_flexible) must be" > " greater than or equal to 1"); > - return; > + return -1; > } > > if (params->sriov_max_vi_per_vf && > @@ -7154,7 +7154,7 @@ static void nvme_check_constraints(NvmeCtrl *n, Error **errp) > error_setg(errp, "sriov_max_vi_per_vf must meet:" > " (sriov_max_vi_per_vf - 1) %% %d == 0 and" > " sriov_max_vi_per_vf >= 1", NVME_VF_RES_GRANULARITY); > - return; > + return -1; > } > > if (params->sriov_max_vq_per_vf && > @@ -7163,9 +7163,11 @@ static void nvme_check_constraints(NvmeCtrl *n, Error **errp) > error_setg(errp, "sriov_max_vq_per_vf must meet:" > " (sriov_max_vq_per_vf - 1) %% %d == 0 and" > " sriov_max_vq_per_vf >= 2", NVME_VF_RES_GRANULARITY); > - return; > + return -1; > } > } > + > + return 0; > } > > static void nvme_init_state(NvmeCtrl *n) > @@ -7564,7 +7566,6 @@ static void nvme_realize(PCIDevice *pci_dev, Error **errp) > { > NvmeCtrl *n = NVME(pci_dev); > NvmeNamespace *ns; > - Error *local_err = NULL; > NvmeCtrl *pn = NVME(pcie_sriov_get_pf(pci_dev)); > > if (pci_is_vf(pci_dev)) { > @@ -7576,9 +7577,7 @@ static void nvme_realize(PCIDevice *pci_dev, Error **errp) > n->subsys = pn->subsys; > } > > - nvme_check_constraints(n, &local_err); > - if (local_err) { > - error_propagate(errp, local_err); > + if (nvme_check_params(n, errp)) { If you stick to int, then please use if (nvme_check_params(n, errp) < 0) { Here's why. A bool-valued function that returns false on error we check like if (!foo()) { A pointer-valued function that returns null on error we also check like if (!foo()) { In both cases, convention makes it obvious we're testing for failure. If you check an int-valued function that returns negative on error like if (foo() < 0) { it's again obvious. However, if you exploit the fact that it returns zero on success in the check like if (foo()) { then convention is of no help to readers. They need to look up what foo() returns to see whether this is checking for success or for failure. Makes sense? > return; > } > > @@ -7586,7 +7585,6 @@ static void nvme_realize(PCIDevice *pci_dev, Error **errp) > &pci_dev->qdev, n->parent_obj.qdev.id); > > if (nvme_init_subsys(n, errp)) { > - error_propagate(errp, local_err); > return; > } > nvme_init_state(n);