drm: add minor-lookup/release helpers

[platform/adaptation/renesas_rcar/renesas_kernel.git] / drivers / gpu / drm / drm_stub.c

diff --git a/drivers/gpu/drm/drm_stub.c b/drivers/gpu/drm/drm_stub.c
index 98a33c5..5b60d8a 100644 (file)
--- a/drivers/gpu/drm/drm_stub.c
+++ b/drivers/gpu/drm/drm_stub.c
@@ -356,6 +356,45 @@ static void drm_unplug_minor(struct drm_minor *minor)
 }
 
 /**
+ * drm_minor_acquire - Acquire a DRM minor
+ * @minor_id: Minor ID of the DRM-minor
+ *
+ * Looks up the given minor-ID and returns the respective DRM-minor object. The
+ * refence-count of the underlying device is increased so you must release this
+ * object with drm_minor_release().
+ *
+ * As long as you hold this minor, it is guaranteed that the object and the
+ * minor->dev pointer will stay valid! However, the device may get unplugged and
+ * unregistered while you hold the minor.
+ *
+ * Returns:
+ * Pointer to minor-object with increased device-refcount, or PTR_ERR on
+ * failure.
+ */
+struct drm_minor *drm_minor_acquire(unsigned int minor_id)
+{
+       struct drm_minor *minor;
+
+       minor = idr_find(&drm_minors_idr, minor_id);
+       if (!minor)
+               return ERR_PTR(-ENODEV);
+
+       drm_dev_ref(minor->dev);
+       return minor;
+}
+
+/**
+ * drm_minor_release - Release DRM minor
+ * @minor: Pointer to DRM minor object
+ *
+ * Release a minor that was previously acquired via drm_minor_acquire().
+ */
+void drm_minor_release(struct drm_minor *minor)
+{
+       drm_dev_unref(minor->dev);
+}
+
+/**
  * drm_put_minor - Destroy DRM minor
  * @minor: Minor to destroy
  *