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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 980E1C0650E for ; Mon, 1 Jul 2019 17:24:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7A80421479 for ; Mon, 1 Jul 2019 17:24:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729259AbfGARYn (ORCPT ); Mon, 1 Jul 2019 13:24:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33350 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727702AbfGARYn (ORCPT ); Mon, 1 Jul 2019 13:24:43 -0400 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 mx1.redhat.com (Postfix) with ESMTPS id 1ACDDC057F2E; Mon, 1 Jul 2019 17:24:43 +0000 (UTC) Received: from x1.home (ovpn-116-83.phx2.redhat.com [10.3.116.83]) by smtp.corp.redhat.com (Postfix) with ESMTP id C25185D70D; Mon, 1 Jul 2019 17:24:42 +0000 (UTC) Date: Mon, 1 Jul 2019 11:24:42 -0600 From: Alex Williamson To: Kirti Wankhede Cc: , , Subject: Re: [PATCH v2] mdev: Send uevents around parent device registration Message-ID: <20190701112442.176a8407@x1.home> In-Reply-To: <08597ab4-cc37-3973-8927-f1bc430f6185@nvidia.com> References: <156199271955.1646.13321360197612813634.stgit@gimli.home> <08597ab4-cc37-3973-8927-f1bc430f6185@nvidia.com> Organization: Red Hat MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Mon, 01 Jul 2019 17:24:43 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Mon, 1 Jul 2019 22:43:10 +0530 Kirti Wankhede wrote: > On 7/1/2019 8:24 PM, Alex Williamson wrote: > > This allows udev to trigger rules when a parent device is registered > > or unregistered from mdev. > > > > Signed-off-by: Alex Williamson > > --- > > > > v2: Don't remove the dev_info(), Kirti requested they stay and > > removing them is only tangential to the goal of this change. > > > > Thanks. > > > > drivers/vfio/mdev/mdev_core.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c > > index ae23151442cb..7fb268136c62 100644 > > --- a/drivers/vfio/mdev/mdev_core.c > > +++ b/drivers/vfio/mdev/mdev_core.c > > @@ -146,6 +146,8 @@ int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops) > > { > > int ret; > > struct mdev_parent *parent; > > + char *env_string = "MDEV_STATE=registered"; > > + char *envp[] = { env_string, NULL }; > > > > /* check for mandatory ops */ > > if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups) > > @@ -197,6 +199,8 @@ int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops) > > mutex_unlock(&parent_list_lock); > > > > dev_info(dev, "MDEV: Registered\n"); > > + kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp); > > + > > return 0; > > > > add_dev_err: > > @@ -220,6 +224,8 @@ EXPORT_SYMBOL(mdev_register_device); > > void mdev_unregister_device(struct device *dev) > > { > > struct mdev_parent *parent; > > + char *env_string = "MDEV_STATE=unregistered"; > > + char *envp[] = { env_string, NULL }; > > > > mutex_lock(&parent_list_lock); > > parent = __find_parent_device(dev); > > @@ -243,6 +249,8 @@ void mdev_unregister_device(struct device *dev) > > up_write(&parent->unreg_sem); > > > > mdev_put_parent(parent); > > + > > + kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp); > > mdev_put_parent() calls put_device(dev). If this is the last instance > holding device, then on put_device(dev) dev would get freed. > > This event should be before mdev_put_parent() So you're suggesting the vendor driver is calling mdev_unregister_device() without a reference to the struct device that it's passing to unregister? Sounds bogus to me. We take a reference to the device so that it can't disappear out from under us, the caller cannot rely on our reference and the caller provided the struct device. Thanks, Alex