From e7fd8b68404f3d8bc03f85bc3c078d67096be06f Mon Sep 17 00:00:00 2001
From: Kai-Heng Feng <kai.heng.feng@canonical.com>
Date: Thu, 29 Sep 2022 15:05:23 +0800
Subject: [PATCH] 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>
---
include/linux/reboot.h | 8 ++++++++
kernel/reboot.c | 17 +++++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/include/linux/reboot.h b/include/linux/reboot.h
index e5d9ef886179c..2b6bb593be5b6 100644
--- 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 3c35445bf5ad3..3bba88c7ffc6b 100644
--- 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;
--
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