From patchwork Thu Jul 14 22:34:56 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sakari Ailus X-Patchwork-Id: 9230793 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 8552860574 for ; Thu, 14 Jul 2016 22:35:29 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7598B281DB for ; Thu, 14 Jul 2016 22:35:29 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6A57A28319; Thu, 14 Jul 2016 22:35:29 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 02B09281DB for ; Thu, 14 Jul 2016 22:35:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752240AbcGNWf0 (ORCPT ); Thu, 14 Jul 2016 18:35:26 -0400 Received: from nblzone-211-213.nblnetworks.fi ([83.145.211.213]:40442 "EHLO hillosipuli.retiisi.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751459AbcGNWfX (ORCPT ); Thu, 14 Jul 2016 18:35:23 -0400 Received: from lanttu.localdomain (lanttu-e.localdomain [192.168.1.64]) by hillosipuli.retiisi.org.uk (Postfix) with ESMTP id A8EEF60098; Fri, 15 Jul 2016 01:35:16 +0300 (EEST) From: Sakari Ailus To: linux-media@vger.kernel.org Cc: mchehab@osg.samsung.com, shuahkh@osg.samsung.com, laurent.pinchart@ideasonboard.com, hverkuil@xs4all.nl Subject: [RFC 01/16] Revert "[media] media: fix media devnode ioctl/syscall and unregister race" Date: Fri, 15 Jul 2016 01:34:56 +0300 Message-Id: <1468535711-13836-2-git-send-email-sakari.ailus@linux.intel.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1468535711-13836-1-git-send-email-sakari.ailus@linux.intel.com> References: <1468535711-13836-1-git-send-email-sakari.ailus@linux.intel.com> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This reverts commit 6f0dd24a084a ("[media] media: fix media devnode ioctl/syscall and unregister race"). The commit was part of an original patchset to avoid crashes when an unregistering device is in use. Signed-off-by: Sakari Ailus --- drivers/media/media-device.c | 15 +++++++-------- drivers/media/media-devnode.c | 8 +------- include/media/media-devnode.h | 16 ++-------------- 3 files changed, 10 insertions(+), 29 deletions(-) diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c index 1795abe..33a9952 100644 --- a/drivers/media/media-device.c +++ b/drivers/media/media-device.c @@ -732,7 +732,6 @@ int __must_check __media_device_register(struct media_device *mdev, if (ret < 0) { /* devnode free is handled in media_devnode_*() */ mdev->devnode = NULL; - media_devnode_unregister_prepare(devnode); media_devnode_unregister(devnode); return ret; } @@ -789,9 +788,6 @@ void media_device_unregister(struct media_device *mdev) return; } - /* Clear the devnode register bit to avoid races with media dev open */ - media_devnode_unregister_prepare(mdev->devnode); - /* Remove all entities from the media device */ list_for_each_entry_safe(entity, next, &mdev->entities, graph_obj.list) __media_device_unregister_entity(entity); @@ -812,10 +808,13 @@ void media_device_unregister(struct media_device *mdev) dev_dbg(mdev->dev, "Media device unregistered\n"); - device_remove_file(&mdev->devnode->dev, &dev_attr_model); - media_devnode_unregister(mdev->devnode); - /* devnode free is handled in media_devnode_*() */ - mdev->devnode = NULL; + /* Check if mdev devnode was registered */ + if (media_devnode_is_registered(mdev->devnode)) { + device_remove_file(&mdev->devnode->dev, &dev_attr_model); + media_devnode_unregister(mdev->devnode); + /* devnode free is handled in media_devnode_*() */ + mdev->devnode = NULL; + } } EXPORT_SYMBOL_GPL(media_device_unregister); diff --git a/drivers/media/media-devnode.c b/drivers/media/media-devnode.c index f2772ba..5b605ff 100644 --- a/drivers/media/media-devnode.c +++ b/drivers/media/media-devnode.c @@ -287,7 +287,7 @@ cdev_add_error: return ret; } -void media_devnode_unregister_prepare(struct media_devnode *devnode) +void media_devnode_unregister(struct media_devnode *devnode) { /* Check if devnode was ever registered at all */ if (!media_devnode_is_registered(devnode)) @@ -295,12 +295,6 @@ void media_devnode_unregister_prepare(struct media_devnode *devnode) mutex_lock(&media_devnode_lock); clear_bit(MEDIA_FLAG_REGISTERED, &devnode->flags); - mutex_unlock(&media_devnode_lock); -} - -void media_devnode_unregister(struct media_devnode *devnode) -{ - mutex_lock(&media_devnode_lock); /* Delete the cdev on this minor as well */ cdev_del(&devnode->cdev); mutex_unlock(&media_devnode_lock); diff --git a/include/media/media-devnode.h b/include/media/media-devnode.h index 37d4948..d5037a9 100644 --- a/include/media/media-devnode.h +++ b/include/media/media-devnode.h @@ -127,26 +127,14 @@ int __must_check media_devnode_register(struct media_device *mdev, struct module *owner); /** - * media_devnode_unregister_prepare - clear the media device node register bit - * @devnode: the device node to prepare for unregister - * - * This clears the passed device register bit. Future open calls will be met - * with errors. Should be called before media_devnode_unregister() to avoid - * races with unregister and device file open calls. - * - * This function can safely be called if the device node has never been - * registered or has already been unregistered. - */ -void media_devnode_unregister_prepare(struct media_devnode *devnode); - -/** * media_devnode_unregister - unregister a media device node * @devnode: the device node to unregister * * This unregisters the passed device. Future open calls will be met with * errors. * - * Should be called after media_devnode_unregister_prepare() + * This function can safely be called if the device node has never been + * registered or has already been unregistered. */ void media_devnode_unregister(struct media_devnode *devnode);