From patchwork Wed Dec 20 10:36:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sakari Ailus X-Patchwork-Id: 756747 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E1B2B208DF for ; Wed, 20 Dec 2023 10:37:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="n08vFq4d" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1703068641; x=1734604641; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=fn5vdqTgrAwxvRPY8aEkpwtLLDHNckvF5vsntZp7xeE=; b=n08vFq4dquIqyXkwV4tARzvC2JBNbMinLia5xRRa9+xjkyq1SxPbhtIA sJklQJCrQokicqv//C2b4Pn1RZAEt6YPNLtGbCUagi9/Q+QkIZo8X1w3O kyAKiQJ01Zno/WQxNi4AymHNvMs8ZUlpj0BUufh8lY2dzG+0a0pho+s06 OYaVQTQM3Mt9nOJrlZZS1SFMLJ2JdtIGKFVBFFn1osWBluSE/NLFhru23 00kYaBe4f8Y77cZJLlBqKyPP0FwXg0weYrRW5clgb1E/wTdSBFDRg78UH IR43X/YYY2JPX2H18/g1b+G4uINCl7ENyQmR8tKzFGxkOzasUVCijWSfN Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10929"; a="9174301" X-IronPort-AV: E=Sophos;i="6.04,291,1695711600"; d="scan'208";a="9174301" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orvoesa102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Dec 2023 02:37:19 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10929"; a="769544226" X-IronPort-AV: E=Sophos;i="6.04,291,1695711600"; d="scan'208";a="769544226" Received: from turnipsi.fi.intel.com (HELO kekkonen.fi.intel.com) ([10.237.72.44]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Dec 2023 02:37:17 -0800 Received: from svinhufvud.ger.corp.intel.com (localhost [IPv6:::1]) by kekkonen.fi.intel.com (Postfix) with ESMTP id 947F811FC49; Wed, 20 Dec 2023 12:37:14 +0200 (EET) From: Sakari Ailus To: linux-media@vger.kernel.org Cc: laurent.pinchart@ideasonboard.com, Hans Verkuil Subject: [PATCH v2 01/29] Revert "[media] media: fix media devnode ioctl/syscall and unregister race" Date: Wed, 20 Dec 2023 12:36:45 +0200 Message-Id: <20231220103713.113386-2-sakari.ailus@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231220103713.113386-1-sakari.ailus@linux.intel.com> References: <20231220103713.113386-1-sakari.ailus@linux.intel.com> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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 Acked-by: Hans Verkuil --- drivers/media/mc/mc-device.c | 15 +++++++-------- drivers/media/mc/mc-devnode.c | 8 +------- include/media/media-devnode.h | 16 ++-------------- 3 files changed, 10 insertions(+), 29 deletions(-) diff --git a/drivers/media/mc/mc-device.c b/drivers/media/mc/mc-device.c index c0dd4ae57227..6c569ecd4b3d 100644 --- a/drivers/media/mc/mc-device.c +++ b/drivers/media/mc/mc-device.c @@ -741,7 +741,6 @@ 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; } @@ -797,9 +796,6 @@ 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); @@ -824,10 +820,13 @@ 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/mc/mc-devnode.c b/drivers/media/mc/mc-devnode.c index 680fbb3a9340..0ab33214d243 100644 --- a/drivers/media/mc/mc-devnode.c +++ b/drivers/media/mc/mc-devnode.c @@ -267,7 +267,7 @@ 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)) @@ -275,12 +275,6 @@ 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_device_del(&devnode->cdev, &devnode->dev); devnode->media_dev = NULL; diff --git a/include/media/media-devnode.h b/include/media/media-devnode.h index d27c1c646c28..46f0d3ae44d1 100644 --- a/include/media/media-devnode.h +++ b/include/media/media-devnode.h @@ -115,19 +115,6 @@ int __must_check media_devnode_register(struct media_device *mdev, struct media_devnode *devnode, 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 @@ -135,7 +122,8 @@ void media_devnode_unregister_prepare(struct media_devnode *devnode); * 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);