module: add MODULE_STATE_GOING notifier call

Provide module unload callback. Required by the gcov profiling
infrastructure to keep track of profiling data structures.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

kernel/module.c

diff --git a/kernel/module.c b/kernel/module.c
index d2d093e..8674a39 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -745,12 +745,13 @@
 	if (!forced && module_refcount(mod) != 0)
 		wait_for_zero_refcount(mod);
 
+	mutex_unlock(&module_mutex);
 	/* Final destruction now noone is using it. */
-	if (mod->exit != NULL) {
-		mutex_unlock(&module_mutex);
+	if (mod->exit != NULL)
 		mod->exit();
-		mutex_lock(&module_mutex);
-	}
+	blocking_notifier_call_chain(&module_notify_list,
+				     MODULE_STATE_GOING, mod);
+	mutex_lock(&module_mutex);
 	/* Store the name of the last unloaded module for diagnostic purposes */
 	strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module));
 	free_module(mod);
@@ -2191,6 +2192,8 @@
 		mod->state = MODULE_STATE_GOING;
 		synchronize_sched();
 		module_put(mod);
+		blocking_notifier_call_chain(&module_notify_list,
+					     MODULE_STATE_GOING, mod);
 		mutex_lock(&module_mutex);
 		free_module(mod);
 		mutex_unlock(&module_mutex);