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Commit d2b34ee6 authored by Daniel Vetter's avatar Daniel Vetter
Browse files

drm: Protect authmagic with master_mutex 



Simplifies cleanup, and there's no reason drivers should ever care
about authmagic at all - it's all handled in the core.

And with that, Ladies and Gentlemen, it's time to pop the champagen
and celebrate: dev->struct_mutex is now officially gone from modern
drivers, and if a driver is using gem_free_object_unlocked and doesn't
do anything else silly it's positively impossible to ever touch
dev->struct_mutex at runtime, anywhere.

Well except for the mutex_init on driver load ;-)

v2: Rebased.

Cc: Chris Wilson <chris@chris-wilson.co.uk> (v1)
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v1)
Reviewed-by: default avatarEmil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1466148814-8194-4-git-send-email-daniel.vetter@ffwll.ch
parent a77316bf

drivers/gpu/drm/drm_auth.c

+6 −8
Original line number Diff line number Diff line
@@ -49,7 +49,7 @@ int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv) 
	struct drm_auth *auth = data;

	int ret = 0;



	mutex_lock(&dev->struct_mutex);

	mutex_lock(&dev->master_mutex);

	if (!file_priv->magic) {

		ret = idr_alloc(&file_priv->master->magic_map, file_priv,

				1, 0, GFP_KERNEL);
@@ -57,7 +57,7 @@ int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv) 
			file_priv->magic = ret;

	}

	auth->magic = file_priv->magic;

	mutex_unlock(&dev->struct_mutex);

	mutex_unlock(&dev->master_mutex);



	DRM_DEBUG("%u\n", auth->magic);
@@ -82,13 +82,13 @@ int drm_authmagic(struct drm_device *dev, void *data, 


	DRM_DEBUG("%u\n", auth->magic);



	mutex_lock(&dev->struct_mutex);

	mutex_lock(&dev->master_mutex);

	file = idr_find(&file_priv->master->magic_map, auth->magic);

	if (file) {

		file->authenticated = 1;

		idr_replace(&file_priv->master->magic_map, NULL, auth->magic);

	}

	mutex_unlock(&dev->struct_mutex);

	mutex_unlock(&dev->master_mutex);



	return file ? 0 : -EINVAL;

}
@@ -117,7 +117,7 @@ static struct drm_master *drm_master_create(struct drm_device *dev) 
 * @dev: The associated device.

 * @fpriv: File private identifying the client.

 *

 * This function must be called with dev::struct_mutex held.

 * This function must be called with dev::master_mutex held.

 * Returns negative error code on failure. Zero on success.

 */

static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
@@ -248,12 +248,10 @@ void drm_master_release(struct drm_file *file_priv) 
	struct drm_device *dev = file_priv->minor->dev;

	struct drm_master *master = file_priv->master;



	mutex_lock(&dev->struct_mutex);

	mutex_lock(&dev->master_mutex);

	if (file_priv->magic)

		idr_remove(&file_priv->master->magic_map, file_priv->magic);

	mutex_unlock(&dev->struct_mutex);



	mutex_lock(&dev->master_mutex);

	if (!file_priv->is_master)

		goto out;