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_PASS autolearn=ham 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 8F40AC43381 for ; Mon, 25 Mar 2019 11:59:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 677FF20863 for ; Mon, 25 Mar 2019 11:59:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731096AbfCYL7H (ORCPT ); Mon, 25 Mar 2019 07:59:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52782 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730837AbfCYL7G (ORCPT ); Mon, 25 Mar 2019 07:59:06 -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 824E53060487; Mon, 25 Mar 2019 11:59:06 +0000 (UTC) Received: from maximlenovopc.usersys.redhat.com (unknown [10.35.206.72]) by smtp.corp.redhat.com (Postfix) with ESMTP id 76E866EDB1; Mon, 25 Mar 2019 11:58:56 +0000 (UTC) Message-ID: <2eb96074b91bb9b8cc2c46c6e1d0e20e790a8531.camel@redhat.com> Subject: Re: [PATCH 7/8] vfio/mdev: Fix aborting mdev child device removal if one fails From: Maxim Levitsky To: Parav Pandit , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, kwankhede@nvidia.com, alex.williamson@redhat.com Date: Mon, 25 Mar 2019 13:58:55 +0200 In-Reply-To: <1553296835-37522-8-git-send-email-parav@mellanox.com> References: <1553296835-37522-1-git-send-email-parav@mellanox.com> <1553296835-37522-8-git-send-email-parav@mellanox.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 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 [10.5.110.47]); Mon, 25 Mar 2019 11:59:06 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2019-03-22 at 18:20 -0500, Parav Pandit wrote: > device_for_each_child() stops executing callback function for remaining > child devices, if callback hits an error. > Each child mdev device is independent of each other. > While unregistering parent device, mdev core must remove all child mdev > devices. > Therefore, mdev_device_remove_cb() always returns success so that > device_for_each_child doesn't abort if one child removal hits error. > > While at it, improve remove and unregister functions for below simplicity. > > There isn't need to pass forced flag pointer during mdev parent > removal which invokes mdev_device_remove(). So simplify the flow. > > mdev_device_remove() is called from two paths. > 1. mdev_unregister_driver() > mdev_device_remove_cb() > mdev_device_remove() > 2. remove_store() > mdev_device_remove() > > When device is removed by user using remote_store(), device under > removal is mdev device. > When device is removed during parent device removal using generic child > iterator, mdev check is already done using dev_is_mdev(). > > Hence, remove the unnecessary loop in mdev_device_remove(). > > Fixes: 7b96953bc640 ("vfio: Mediated device Core driver") > Signed-off-by: Parav Pandit > --- > drivers/vfio/mdev/mdev_core.c | 24 +++++------------------- > 1 file changed, 5 insertions(+), 19 deletions(-) > > diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c > index ab05464..944a058 100644 > --- a/drivers/vfio/mdev/mdev_core.c > +++ b/drivers/vfio/mdev/mdev_core.c > @@ -150,10 +150,10 @@ static int mdev_device_remove_ops(struct mdev_device > *mdev, bool force_remove) > > static int mdev_device_remove_cb(struct device *dev, void *data) > { > - if (!dev_is_mdev(dev)) > - return 0; > + if (dev_is_mdev(dev)) > + mdev_device_remove(dev, true); > > - return mdev_device_remove(dev, data ? *(bool *)data : true); > + return 0; > } > > /* > @@ -241,7 +241,6 @@ int mdev_register_device(struct device *dev, const struct > mdev_parent_ops *ops) > void mdev_unregister_device(struct device *dev) > { > struct mdev_parent *parent; > - bool force_remove = true; > > mutex_lock(&parent_list_lock); > parent = __find_parent_device(dev); > @@ -255,8 +254,7 @@ void mdev_unregister_device(struct device *dev) > list_del(&parent->next); > class_compat_remove_link(mdev_bus_compat_class, dev, NULL); > > - device_for_each_child(dev, (void *)&force_remove, > - mdev_device_remove_cb); > + device_for_each_child(dev, NULL, mdev_device_remove_cb); > > parent_remove_sysfs_files(parent); > > @@ -346,24 +344,12 @@ int mdev_device_create(struct kobject *kobj, struct > device *dev, uuid_le uuid) > > int mdev_device_remove(struct device *dev, bool force_remove) > { > - struct mdev_device *mdev, *tmp; > + struct mdev_device *mdev; > struct mdev_parent *parent; > struct mdev_type *type; > int ret; > > mdev = to_mdev_device(dev); > - > - mutex_lock(&mdev_list_lock); > - list_for_each_entry(tmp, &mdev_list, next) { > - if (tmp == mdev) > - break; > - } > - > - if (tmp != mdev) { > - mutex_unlock(&mdev_list_lock); > - return -ENODEV; > - } > - > if (!mdev->active) { > mutex_unlock(&mdev_list_lock); > return -EAGAIN; Very nice catch and good refactoring. Reviewed-by: Maxim Levitsky Best regards, Maxim Levitsky