drm: Populate fb->dev from drm_helper_mode_fill_fb_struct()

Populating fb->dev before drm_framebuffer_init() allows us to use
fb->dev already while validating the framebuffer. Let's have
drm_helper_mode_fill_fb_struct() do that for us.

Also make drm_framebuffer_init() warn us if a different device
pointer is passed to it than was passed to
drm_helper_mode_fill_fb_struct().

v2: Reject fbs with invalid fb->dev (Laurent)

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com> (v1)
Link: http://patchwork.freedesktop.org/patch/msgid/1479498793-31021-19-git-send-email-ville.syrjala@linux.intel.com

2 files changed, 5 insertions, 1 deletions

diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
index cbf0c893f426..f397565d3c20 100644
--- a/drivers/gpu/drm/drm_framebuffer.c
+++ b/drivers/gpu/drm/drm_framebuffer.c
@@ -631,8 +631,11 @@ int drm_framebuffer_init(struct drm_device *dev, struct drm_framebuffer *fb,
 {
         int ret;
 
+        if (WARN_ON_ONCE(fb->dev != dev))
+                return -EINVAL;
+
         INIT_LIST_HEAD(&fb->filp_head);
-        fb->dev = dev;
+
         fb->funcs = funcs;
 
         ret = drm_mode_object_get_reg(dev, &fb->base, DRM_MODE_OBJECT_FB,
diff --git a/drivers/gpu/drm/drm_modeset_helper.c b/drivers/gpu/drm/drm_modeset_helper.c
index 285ffcba0fe8..57a319e3f780 100644
--- a/drivers/gpu/drm/drm_modeset_helper.c
+++ b/drivers/gpu/drm/drm_modeset_helper.c
@@ -90,6 +90,7 @@ void drm_helper_mode_fill_fb_struct(struct drm_device *dev,
                 fb->bits_per_pixel = info->cpp[0] * 8;
         }
 
+        fb->dev = dev;
         fb->width = mode_cmd->width;
         fb->height = mode_cmd->height;
         for (i = 0; i < 4; i++) {