PM / wakeup: Drop wakeup_source_init(), wakeup_source_prepare()

wakeup_source_init() has no users. Remove it.

As a result, wakeup_source_prepare() is only called from
wakeup_source_create(). Merge wakeup_source_prepare() into
wakeup_source_create() and remove it.

Change wakeup_source_create() behavior so that assigning NULL to wakeup
source's name throws an error.

Signed-off-by: Tri Vo <trong@android.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/wakeup.c

@@ -72,23 +72,6 @@ static struct wakeup_source deleted_ws = {
 	.lock =  __SPIN_LOCK_UNLOCKED(deleted_ws.lock),
 };
 
-/**
- * wakeup_source_prepare - Prepare a new wakeup source for initialization.
- * @ws: Wakeup source to prepare.
- * @name: Pointer to the name of the new wakeup source.
- *
- * Callers must ensure that the @name string won't be freed when @ws is still in
- * use.
- */
-void wakeup_source_prepare(struct wakeup_source *ws, const char *name)
-{
-	if (ws) {
-		memset(ws, 0, sizeof(*ws));
-		ws->name = name;
-	}
-}
-EXPORT_SYMBOL_GPL(wakeup_source_prepare);
-
 /**
  * wakeup_source_create - Create a struct wakeup_source object.
  * @name: Name of the new wakeup source.
@@ -96,13 +79,23 @@ EXPORT_SYMBOL_GPL(wakeup_source_prepare);
 struct wakeup_source *wakeup_source_create(const char *name)
 {
 	struct wakeup_source *ws;
+	const char *ws_name;
 
-	ws = kmalloc(sizeof(*ws), GFP_KERNEL);
+	ws = kzalloc(sizeof(*ws), GFP_KERNEL);
 	if (!ws)
-		return NULL;
+		goto err_ws;
+
+	ws_name = kstrdup_const(name, GFP_KERNEL);
+	if (!ws_name)
+		goto err_name;
+	ws->name = ws_name;
 
-	wakeup_source_prepare(ws, name ? kstrdup_const(name, GFP_KERNEL) : NULL);
 	return ws;
+
+err_name:
+	kfree(ws);
+err_ws:
+	return NULL;
 }
 EXPORT_SYMBOL_GPL(wakeup_source_create);