drm: Make control nodes master-less v3

Like for render-nodes, there is no point in maintaining the master concept
for control nodes, so set the struct drm_file::master pointer to NULL.

At the same time, make sure DRM_MASTER | DRM_CONTROL_ALLOW ioctls are always
allowed when called through the control node. Previously the caller also
needed to be master.

v2: Adapt to refactoring of ioctl permission check.
v3: Formatting of logical expression. Use drm_is_control_client() instead of
    drm_is_control().

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 05e30530c025..cf2dfb790bf1 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -306,13 +306,14 @@ static int drm_ioctl_permit(u32 flags, struct drm_file *file_priv)
                      !file_priv->authenticated))
                 return -EACCES;
 
-        /* MASTER is only for master */
-        if (unlikely((flags & DRM_MASTER) && !file_priv->is_master))
+        /* MASTER is only for master or control clients */
+        if (unlikely((flags & DRM_MASTER) && !file_priv->is_master &&
+                     !drm_is_control_client(file_priv)))
                 return -EACCES;
 
         /* Control clients must be explicitly allowed */
         if (unlikely(!(flags & DRM_CONTROL_ALLOW) &&
-                     file_priv->minor->type == DRM_MINOR_CONTROL))
+                     drm_is_control_client(file_priv)))
                 return -EACCES;
 
         /* Render clients must be explicitly allowed */