From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from nblzone-211-213.nblnetworks.fi ([83.145.211.213]:35186 "EHLO hillosipuli.retiisi.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751100AbcKHNzd (ORCPT ); Tue, 8 Nov 2016 08:55:33 -0500 From: Sakari Ailus To: linux-media@vger.kernel.org, hverkuil@xs4all.nl Cc: mchehab@osg.samsung.com, shuahkh@osg.samsung.com, laurent.pinchart@ideasonboard.com Subject: [RFC v4 01/21] Revert "[media] media: fix media devnode ioctl/syscall and unregister race" Date: Tue, 8 Nov 2016 15:55:10 +0200 Message-Id: <1478613330-24691-1-git-send-email-sakari.ailus@linux.intel.com> In-Reply-To: <20161108135438.GO3217@valkosipuli.retiisi.org.uk> References: <20161108135438.GO3217@valkosipuli.retiisi.org.uk> Sender: linux-media-owner@vger.kernel.org List-ID: 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 2783531..f2525eb 100644 --- a/drivers/media/media-device.c +++ b/drivers/media/media-device.c @@ -730,7 +730,6 @@ 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; } @@ -787,9 +786,6 @@ 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); @@ -810,10 +806,13 @@ 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 @@ int __must_check media_devnode_register(struct media_device *mdev, 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 cd23e91..d55ec2b 100644 --- a/include/media/media-devnode.h +++ b/include/media/media-devnode.h @@ -128,26 +128,14 @@ 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); -- 2.1.4