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: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1466148814-8194-4-git-send-email-daniel.vetter@ffwll.ch

diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
index 24f0f2dc1cce6c209859883aa3042811489801d6..d858e69d337b24cc7604c3cbe9329bba97deb8bc 100644 (file)
--- a/drivers/gpu/drm/drm_auth.c
+++ b/drivers/gpu/drm/drm_auth.c
@@ -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;