drm: Reshuffle getfb error returns

Make it a little more clear what's going on inside of getfb, and also
make it easier to add alternate paths to get a handle in future.

Signed-off-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180323134553.15993-3-daniels@collabora.com

diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
index ad67203..8c4d32a 100644 (file)
--- a/drivers/gpu/drm/drm_framebuffer.c
+++ b/drivers/gpu/drm/drm_framebuffer.c
@@ -468,29 +468,31 @@ int drm_mode_getfb(struct drm_device *dev,
                goto out;
        }
 
+       if (!fb->funcs->create_handle) {
+               ret = -ENODEV;
+               goto out;
+       }
+
        r->height = fb->height;
        r->width = fb->width;
        r->depth = fb->format->depth;
        r->bpp = fb->format->cpp[0] * 8;
        r->pitch = fb->pitches[0];
-       if (fb->funcs->create_handle) {
-               if (drm_is_current_master(file_priv) || capable(CAP_SYS_ADMIN) ||
-                   drm_is_control_client(file_priv)) {
-                       ret = fb->funcs->create_handle(fb, file_priv,
-                                                      &r->handle);
-               } else {
-                       /* GET_FB() is an unprivileged ioctl so we must not
-                        * return a buffer-handle to non-master processes! For
-                        * backwards-compatibility reasons, we cannot make
-                        * GET_FB() privileged, so just return an invalid handle
-                        * for non-masters. */
-                       r->handle = 0;
-                       ret = 0;
-               }
-       } else {
-               ret = -ENODEV;
+
+       /* GET_FB() is an unprivileged ioctl so we must not return a
+        * buffer-handle to non-master processes! For
+        * backwards-compatibility reasons, we cannot make GET_FB() privileged,
+        * so just return an invalid handle for non-masters.
+        */
+       if (!drm_is_current_master(file_priv) && !capable(CAP_SYS_ADMIN) &&
+           !drm_is_control_client(file_priv)) {
+               r->handle = 0;
+               ret = 0;
+               goto out;
        }
 
+       ret = fb->funcs->create_handle(fb, file_priv, &r->handle);
+
 out:
        drm_framebuffer_put(fb);