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spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:49852 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lmITG-0001gz-Pn for qemu-devel@archiver.kernel.org; Thu, 27 May 2021 12:02:54 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58994) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lmIQE-0007Wg-Mk for qemu-devel@nongnu.org; Thu, 27 May 2021 11:59:46 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:49725) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lmIQC-00077r-Cf for qemu-devel@nongnu.org; Thu, 27 May 2021 11:59:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1622131182; 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=iq3/KZ7IAu4fYVHKvJToAIdCbMM1tPOI/jWQKHAJwoo=; b=FMty2HbmJ0gTwrCrUbZVjqB3boJNAT/Vif1cH9REQvMDlAUdcCCU2A75yc1tzfgF7ZqnVR wrknI7XfdedFRrA/sGv48WIBRHQzGTapc6k3OTHcRmjMtjxI38TY0nV9QDu+S1RpH6nzDp fjYlQKcygCCb5ZGR2+Ed2FBDhmA20oc= 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-533-cPcNCpf8OriUYUslO_mqQw-1; Thu, 27 May 2021 11:59:40 -0400 X-MC-Unique: cPcNCpf8OriUYUslO_mqQw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E8CAE801106; Thu, 27 May 2021 15:59:39 +0000 (UTC) Received: from work-vm (ovpn-114-249.ams2.redhat.com [10.36.114.249]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B9BE25B689; Thu, 27 May 2021 15:59:32 +0000 (UTC) Date: Thu, 27 May 2021 16:59:29 +0100 From: "Dr. David Alan Gilbert" To: Stefan Hajnoczi Subject: Re: [PATCH v3 03/26] DAX: vhost-user: Rework slave return values Message-ID: References: <20210428110100.27757-1-dgilbert@redhat.com> <20210428110100.27757-4-dgilbert@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 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.374, 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_H4=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: virtio-fs@redhat.com, qemu-devel@nongnu.org, vgoyal@redhat.com, groug@kaod.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Stefan Hajnoczi (stefanha@redhat.com) wrote: > On Wed, Apr 28, 2021 at 12:00:37PM +0100, Dr. David Alan Gilbert (git) wrote: > > From: "Dr. David Alan Gilbert" > > > > All the current slave handlers on the qemu side generate an 'int' > > return value that's squashed down to a bool (!!ret) and stuffed into > > a uint64_t (field of a union) to be returned. > > > > Move the uint64_t type back up through the individual handlers so > > that we can make one actually return a full uint64_t. > > > > Note that the definition in the interop spec says most of these > > cases are defined as returning 0 on success and non-0 for failure, > > so it's OK to change from a bool to another non-0. > > > > Vivek: > > This is needed because upcoming patches in series will add new functions > > which want to return full error code. Existing functions continue to > > return true/false so, it should not lead to change of behavior for > > existing users. > > > > Signed-off-by: Dr. David Alan Gilbert > > Reviewed-by: Greg Kurz > > --- > > hw/virtio/vhost-backend.c | 6 +++--- > > hw/virtio/vhost-user.c | 31 ++++++++++++++++--------------- > > include/hw/virtio/vhost-backend.h | 2 +- > > 3 files changed, 20 insertions(+), 19 deletions(-) > > > > diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c > > index 31b33bde37..1686c94767 100644 > > --- a/hw/virtio/vhost-backend.c > > +++ b/hw/virtio/vhost-backend.c > > @@ -401,8 +401,8 @@ int vhost_backend_invalidate_device_iotlb(struct vhost_dev *dev, > > return -ENODEV; > > } > > > > -int vhost_backend_handle_iotlb_msg(struct vhost_dev *dev, > > - struct vhost_iotlb_msg *imsg) > > +uint64_t vhost_backend_handle_iotlb_msg(struct vhost_dev *dev, > > + struct vhost_iotlb_msg *imsg) > > { > > int ret = 0; > > This patch is messy. We want uint64_t but these functions use int ret > internally. The actual return values are true/false instead of int 0 and > 1. Yeh. > Please use uint64_t everywhere: return 0 for success and 1 for failure > instead of bool literals and change the type of the local ret variables > to uint64_t. OK, reworked, this part of it now looks like : int vhost_backend_handle_iotlb_msg(struct vhost_dev *dev, - struct vhost_iotlb_msg *imsg) +uint64_t vhost_backend_handle_iotlb_msg(struct vhost_dev *dev, + struct vhost_iotlb_msg *imsg) { - int ret = 0; + uint64_t ret = 0; if (unlikely(!dev->vdev)) { error_report("Unexpected IOTLB message when virtio device is stopped"); - return -EINVAL; + return EINVAL; } switch (imsg->type) { case VHOST_IOTLB_MISS: - ret = vhost_device_iotlb_miss(dev, imsg->iova, - imsg->perm != VHOST_ACCESS_RO); + ret = -vhost_device_iotlb_miss(dev, imsg->iova, + imsg->perm != VHOST_ACCESS_RO); break; case VHOST_IOTLB_ACCESS_FAIL: /* FIXME: report device iotlb error */ error_report("Access failure IOTLB message type not supported"); - ret = -ENOTSUP; + ret = ENOTSUP; break; case VHOST_IOTLB_UPDATE: case VHOST_IOTLB_INVALIDATE: default: error_report("Unexpected IOTLB message type"); - ret = -EINVAL; + ret = EINVAL; break; } -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK