[PATCH 21/51] drm: Use drmm_ for drm_dev_init cleanup

From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: DRI Development <dri-devel@lists.freedesktop.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
	Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
	Daniel Vetter <daniel.vetter@intel.com>
Subject: [PATCH 21/51] drm: Use drmm_ for drm_dev_init cleanup
Date: Mon, 23 Mar 2020 15:49:20 +0100	[thread overview]
Message-ID: <20200323144950.3018436-22-daniel.vetter@ffwll.ch> (raw)
In-Reply-To: <20200323144950.3018436-1-daniel.vetter@ffwll.ch>

Well for the simple stuff at least, vblank, gem and minor cleanup I
want to further split up as a demonstration.

v2: We need to clear drm_device->dev otherwise the debug drm printing
after our cleanup hook (e.g. in drm_manged_release) will chase
released memory and result in a use-after-free. Not really pretty, but
oh well.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 drivers/gpu/drm/drm_drv.c | 48 ++++++++++++++++++++-------------------
 1 file changed, 25 insertions(+), 23 deletions(-)

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index c80ebc6811b1..a710c53d13a8 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -580,6 +580,23 @@ static void drm_fs_inode_free(struct inode *inode)
  *    used.
  */
 
+static void drm_dev_init_release(struct drm_device *dev, void *res)
+{
+	drm_legacy_ctxbitmap_cleanup(dev);
+	drm_legacy_remove_map_hash(dev);
+	drm_fs_inode_free(dev->anon_inode);
+
+	put_device(dev->dev);
+	/* Prevent use-after-free in drm_managed_release when debugging is
+	 * enabled. Slightly awkward, but can't really be helped. */
+	dev->dev = NULL;
+	mutex_destroy(&dev->master_mutex);
+	mutex_destroy(&dev->clientlist_mutex);
+	mutex_destroy(&dev->filelist_mutex);
+	mutex_destroy(&dev->struct_mutex);
+	drm_legacy_destroy_members(dev);
+}
+
 /**
  * drm_dev_init - Initialise new DRM device
  * @dev: DRM device
@@ -647,11 +664,15 @@ int drm_dev_init(struct drm_device *dev,
 	mutex_init(&dev->clientlist_mutex);
 	mutex_init(&dev->master_mutex);
 
+	ret = drmm_add_action(dev, drm_dev_init_release, NULL);
+	if (ret)
+		return ret;
+
 	dev->anon_inode = drm_fs_inode_new();
 	if (IS_ERR(dev->anon_inode)) {
 		ret = PTR_ERR(dev->anon_inode);
 		DRM_ERROR("Cannot allocate anonymous inode: %d\n", ret);
-		goto err_free;
+		goto err;
 	}
 
 	if (drm_core_check_feature(dev, DRIVER_RENDER)) {
@@ -688,19 +709,12 @@ int drm_dev_init(struct drm_device *dev,
 	if (drm_core_check_feature(dev, DRIVER_GEM))
 		drm_gem_destroy(dev);
 err_ctxbitmap:
-	drm_legacy_ctxbitmap_cleanup(dev);
-	drm_legacy_remove_map_hash(dev);
 err_minors:
 	drm_minor_free(dev, DRM_MINOR_PRIMARY);
 	drm_minor_free(dev, DRM_MINOR_RENDER);
-	drm_fs_inode_free(dev->anon_inode);
-err_free:
-	put_device(dev->dev);
-	mutex_destroy(&dev->master_mutex);
-	mutex_destroy(&dev->clientlist_mutex);
-	mutex_destroy(&dev->filelist_mutex);
-	mutex_destroy(&dev->struct_mutex);
-	drm_legacy_destroy_members(dev);
+err:
+	drm_managed_release(dev);
+
 	return ret;
 }
 EXPORT_SYMBOL(drm_dev_init);
@@ -763,20 +777,8 @@ void drm_dev_fini(struct drm_device *dev)
 	if (drm_core_check_feature(dev, DRIVER_GEM))
 		drm_gem_destroy(dev);
 
-	drm_legacy_ctxbitmap_cleanup(dev);
-	drm_legacy_remove_map_hash(dev);
-	drm_fs_inode_free(dev->anon_inode);
-
 	drm_minor_free(dev, DRM_MINOR_PRIMARY);
 	drm_minor_free(dev, DRM_MINOR_RENDER);
-
-	put_device(dev->dev);
-
-	mutex_destroy(&dev->master_mutex);
-	mutex_destroy(&dev->clientlist_mutex);
-	mutex_destroy(&dev->filelist_mutex);
-	mutex_destroy(&dev->struct_mutex);
-	drm_legacy_destroy_members(dev);
 }
 EXPORT_SYMBOL(drm_dev_fini);
 
-- 
2.25.1

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