Send reboot notifications to Litmus

This patch causes reboot notifications to be send
to Litmus.  With this patch, Litmus attempts to
switch back to the Linux-plugin before the reboot
proceeds.  Any failures to switch back are reported
via printk() (the reboot is not halted).

1 files changed, 24 insertions, 0 deletions

diff --git a/litmus/litmus.c b/litmus/litmus.c
index c842de46587b..9c6b738ab99d 100644
--- a/litmus/litmus.c
+++ b/litmus/litmus.c
@@ -9,6 +9,7 @@
 #include <linux/sched.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/reboot.h>
 
 #include <litmus/litmus.h>
 #include <litmus/bheap.h>
@@ -528,6 +529,25 @@ static struct sysrq_key_op sysrq_kill_rt_tasks_op = {
 
 extern struct sched_plugin linux_sched_plugin;
 
+static int litmus_shutdown_nb(struct notifier_block *unused1,
+                                unsigned long unused2, void *unused3)
+{
+        /* Attempt to switch back to regular Linux scheduling.
+         * Forces the active plugin to clean up.
+         */
+        if (litmus != &linux_sched_plugin) {
+                int ret = switch_sched_plugin(&linux_sched_plugin);
+                if (ret) {
+                        printk("Auto-shutdown of active Litmus plugin failed.\n");
+                }
+        }
+        return NOTIFY_DONE;
+}
+
+static struct notifier_block shutdown_notifier = {
+        .notifier_call = litmus_shutdown_nb,
+};
+
 static int __init _init_litmus(void)
 {
         /*      Common initializers,
@@ -555,11 +575,15 @@ static int __init _init_litmus(void)
         init_topology();
 #endif
 
+        register_reboot_notifier(&shutdown_notifier);
+
         return 0;
 }
 
 static void _exit_litmus(void)
 {
+        unregister_reboot_notifier(&shutdown_notifier);
+
         exit_litmus_proc();
         kmem_cache_destroy(bheap_node_cache);
         kmem_cache_destroy(release_heap_cache);