kernel/reboot: Add SYS_OFF_MODE_RESTART_PREPARE mode

Add SYS_OFF_MODE_RESTART_PREPARE callbacks to be invoked before
a system restart.

Suggested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/include/linux/reboot.h b/include/linux/reboot.h
index e5d9ef886179c0924a12f98ca8e378a1462e3606..2b6bb593be5b655b3251506841b227813525454c 100644 (file)
--- a/include/linux/reboot.h
+++ b/include/linux/reboot.h
@@ -105,6 +105,14 @@ enum sys_off_mode {
         */
        SYS_OFF_MODE_POWER_OFF,
 
+       /**
+        * @SYS_OFF_MODE_RESTART_PREPARE:
+        *
+        * Handlers prepare system to be restarted. Handlers are
+        * allowed to sleep.
+        */
+       SYS_OFF_MODE_RESTART_PREPARE,
+
        /**
         * @SYS_OFF_MODE_RESTART:
         *

diff --git a/kernel/reboot.c b/kernel/reboot.c
index 3c35445bf5ad34cad207b91e8086e8d8498fa6f6..3bba88c7ffc6be6b86ee69d1b73f64d7beb70542 100644 (file)
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -243,6 +243,17 @@ void migrate_to_reboot_cpu(void)
        set_cpus_allowed_ptr(current, cpumask_of(cpu));
 }
 
+/*
+ *     Notifier list for kernel code which wants to be called
+ *     to prepare system for restart.
+ */
+static BLOCKING_NOTIFIER_HEAD(restart_prep_handler_list);
+
+static void do_kernel_restart_prepare(void)
+{
+       blocking_notifier_call_chain(&restart_prep_handler_list, 0, NULL);
+}
+
 /**
  *     kernel_restart - reboot the system
  *     @cmd: pointer to buffer containing command to execute for restart
@@ -254,6 +265,7 @@ void migrate_to_reboot_cpu(void)
 void kernel_restart(char *cmd)
 {
        kernel_restart_prepare(cmd);
+       do_kernel_restart_prepare();
        migrate_to_reboot_cpu();
        syscore_shutdown();
        if (!cmd)
@@ -396,6 +408,11 @@ register_sys_off_handler(enum sys_off_mode mode,
                handler->list = &power_off_handler_list;
                break;
 
+       case SYS_OFF_MODE_RESTART_PREPARE:
+               handler->list = &restart_prep_handler_list;
+               handler->blocking = true;
+               break;
+
        case SYS_OFF_MODE_RESTART:
                handler->list = &restart_handler_list;
                break;