From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id 264ACA053B; Thu, 6 Feb 2020 12:14:38 +0100 (CET) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 9E43B1C0B9; Thu, 6 Feb 2020 12:14:37 +0100 (CET) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) by dpdk.org (Postfix) with ESMTP id 4886C1BFA1 for ; Thu, 6 Feb 2020 12:14:35 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1580987674; 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=rHTZHgmASPSoMGwevhPMX79nOsZmoqk9zStUKfH69Ac=; b=iuQQoERaiBV5tX7Dus2H45lzJlKqsCLBbMBjwVfvrTD75eBdtsLa7IMuqF43EaWfx6oN1x RIoIoj8Da+HXBX1gvZxbj0b7/GVJDrLdviRgH3b+Kk8qXoewauNv8URYLwrsv7HfIpIE2F OaZ2BFAUzxUv2y9RM6DWmzHxMdVWYe0= 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-160-1MlG-dHJOhuoPlWtqAiYTw-1; Thu, 06 Feb 2020 06:14:31 -0500 X-MC-Unique: 1MlG-dHJOhuoPlWtqAiYTw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4C9141857341; Thu, 6 Feb 2020 11:14:29 +0000 (UTC) Received: from gondolin (dhcp-192-195.str.redhat.com [10.33.192.195]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4670910016DA; Thu, 6 Feb 2020 11:14:22 +0000 (UTC) Date: Thu, 6 Feb 2020 12:14:19 +0100 From: Cornelia Huck To: Alex Williamson Cc: kvm@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, dev@dpdk.org, mtosatti@redhat.com, thomas@monjalon.net, bluca@debian.org, jerinjacobk@gmail.com, bruce.richardson@intel.com Message-ID: <20200206121419.69997326.cohuck@redhat.com> In-Reply-To: <158085754299.9445.4389176548645142886.stgit@gimli.home> References: <158085337582.9445.17682266437583505502.stgit@gimli.home> <158085754299.9445.4389176548645142886.stgit@gimli.home> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Subject: Re: [dpdk-dev] [RFC PATCH 1/7] vfio: Include optional device match in vfio_device_ops callbacks X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Tue, 04 Feb 2020 16:05:43 -0700 Alex Williamson wrote: > Allow bus drivers to provide their own callback to match a device to > the user provided string. > > Signed-off-by: Alex Williamson > --- > drivers/vfio/vfio.c | 19 +++++++++++++++---- > include/linux/vfio.h | 3 +++ > 2 files changed, 18 insertions(+), 4 deletions(-) > > diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c > index 388597930b64..dda1726adda8 100644 > --- a/drivers/vfio/vfio.c > +++ b/drivers/vfio/vfio.c > @@ -875,11 +875,22 @@ EXPORT_SYMBOL_GPL(vfio_device_get_from_dev); > static struct vfio_device *vfio_device_get_from_name(struct vfio_group *group, > char *buf) > { > - struct vfio_device *it, *device = NULL; > + struct vfio_device *it, *device = ERR_PTR(-ENODEV); > > mutex_lock(&group->device_lock); > list_for_each_entry(it, &group->device_list, group_next) { > - if (!strcmp(dev_name(it->dev), buf)) { > + int ret; > + > + if (it->ops->match) { > + ret = it->ops->match(it->device_data, buf); > + if (ret < 0 && ret != -ENODEV) { > + device = ERR_PTR(ret); > + break; > + } > + } else > + ret = strcmp(dev_name(it->dev), buf); The asymmetric braces look a bit odd. > + > + if (!ret) { > device = it; > vfio_device_get(device); > break; > @@ -1441,8 +1452,8 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) > return -EPERM; > > device = vfio_device_get_from_name(group, buf); > - if (!device) > - return -ENODEV; > + if (IS_ERR(device)) > + return PTR_ERR(device); > > ret = device->ops->open(device->device_data); > if (ret) { > diff --git a/include/linux/vfio.h b/include/linux/vfio.h > index e42a711a2800..755e0f0e2900 100644 > --- a/include/linux/vfio.h > +++ b/include/linux/vfio.h > @@ -26,6 +26,8 @@ > * operations documented below > * @mmap: Perform mmap(2) on a region of the device file descriptor > * @request: Request for the bus driver to release the device > + * @match: Optional device name match callback (return: 0 for match, -ENODEV > + * (or >0) for no match and continue, other -errno: no match and stop) I'm wondering about these conventions. If you basically want a tri-state return (match, don't match/continue, don't match/stop), putting -ENODEV and >0 together feels odd. I would rather expect either - < 0 == don't match/stop, 0 == don't match/continue, > 0 == match, or - 0 == match, -ENODEV (or some other defined error) == don't match/continue, all other values == don't match/abort? > */ > struct vfio_device_ops { > char *name; > @@ -39,6 +41,7 @@ struct vfio_device_ops { > unsigned long arg); > int (*mmap)(void *device_data, struct vm_area_struct *vma); > void (*request)(void *device_data, unsigned int count); > + int (*match)(void *device_data, char *buf); > }; > > extern struct iommu_group *vfio_iommu_group_get(struct device *dev); >