[RFC/PATCH] v4l2-ctrls: eliminate lockdep false alarms for struct v4l2_ctrl_handler.lock

Commit Message

Andy Walls Dec. 24, 2010, 1:50 a.m. UTC

None

Patch

diff --git a/drivers/media/video/v4l2-ctrls.c b/drivers/media/video/v4l2-ctrls.c
index 9d2502c..8b7de34 100644
--- a/drivers/media/video/v4l2-ctrls.c
+++ b/drivers/media/video/v4l2-ctrls.c
@@ -761,10 +761,9 @@  static inline int handler_set_err(struct v4l2_ctrl_handler *hdl, int err)
 }
 
 /* Initialize the handler */
-int v4l2_ctrl_handler_init(struct v4l2_ctrl_handler *hdl,
-			   unsigned nr_of_controls_hint)
+int _v4l2_ctrl_handler_init(struct v4l2_ctrl_handler *hdl,
+			    unsigned nr_of_controls_hint)
 {
-	mutex_init(&hdl->lock);
 	INIT_LIST_HEAD(&hdl->ctrls);
 	INIT_LIST_HEAD(&hdl->ctrl_refs);
 	hdl->nr_of_buckets = 1 + nr_of_controls_hint / 8;
@@ -773,7 +772,7 @@  int v4l2_ctrl_handler_init(struct v4l2_ctrl_handler *hdl,
 	hdl->error = hdl->buckets ? 0 : -ENOMEM;
 	return hdl->error;
 }
-EXPORT_SYMBOL(v4l2_ctrl_handler_init);
+EXPORT_SYMBOL(_v4l2_ctrl_handler_init);
 
 /* Free all controls and control refs */
 void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl)
diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index 9b7bea9..3bc0f69 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -238,8 +238,21 @@  void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
   * Returns an error if the buckets could not be allocated. This error will
   * also be stored in @hdl->error.
   */
-int v4l2_ctrl_handler_init(struct v4l2_ctrl_handler *hdl,
-			   unsigned nr_of_controls_hint);
+int _v4l2_ctrl_handler_init(struct v4l2_ctrl_handler *hdl,
+			    unsigned nr_of_controls_hint);
+
+#define v4l2_ctrl_handler_init(hdl, nr_of_controls_hint)		\
+(									\
+	({								\
+		static struct lock_class_key _key;			\
+		mutex_init(&(hdl)->lock);				\
+		lockdep_set_class_and_name(&(hdl)->lock, &_key,		\
+					   KBUILD_BASENAME ":"		\
+					   __stringify(__LINE__) ":"	\
+					   "(" #hdl ")->lock");		\
+	}),								\
+	_v4l2_ctrl_handler_init(hdl, nr_of_controls_hint)		\
+)
 
 /** v4l2_ctrl_handler_free() - Free all controls owned by the handler and free
   * the control list.