[PATCH v1 3/6] kernel: Add devm_register_restart_handler()

[Dmitry Osipenko <digetx@gmail.com>]

Add resource-managed variant of register_restart_handler().

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 include/linux/reboot.h |  2 ++
 kernel/reboot.c        | 27 +++++++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/include/linux/reboot.h b/include/linux/reboot.h
index f72fb8729608..fb17fad63e53 100644
--- a/include/linux/reboot.h
+++ b/include/linux/reboot.h
@@ -49,6 +49,8 @@ extern int register_restart_handler(struct notifier_block *);
 extern int unregister_restart_handler(struct notifier_block *);
 extern void do_kernel_restart(char *cmd);
 
+extern int devm_register_restart_handler(struct device *, struct notifier_block *);
+
 extern int register_poweroff_handler(struct notifier_block *);
 extern int unregister_poweroff_handler(struct notifier_block *);
 
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 6e90afec2bb8..b611e49a5ac6 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -200,6 +200,33 @@ int unregister_restart_handler(struct notifier_block *nb)
 }
 EXPORT_SYMBOL(unregister_restart_handler);
 
+static void devm_unregister_restart_handler(struct device *dev, void *res)
+{
+	WARN_ON(unregister_restart_handler(*(struct notifier_block **)res));
+}
+
+int devm_register_restart_handler(struct device *dev, struct notifier_block *nb)
+{
+	struct notifier_block **rcnb;
+	int ret;
+
+	rcnb = devres_alloc(devm_unregister_restart_handler,
+			    sizeof(*rcnb), GFP_KERNEL);
+	if (!rcnb)
+		return -ENOMEM;
+
+	ret = register_restart_handler(nb);
+	if (!ret) {
+		*rcnb = nb;
+		devres_add(dev, rcnb);
+	} else {
+		devres_free(rcnb);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(devm_register_restart_handler);
+
 /**
  *	do_kernel_restart - Execute kernel restart handler call chain
  *
-- 
2.32.0