kernel/reboot: Add device to sys_off_handler

If the dev is known (e.g. a devm-based sys_off_handler is used), it can
be passed to the handler's callback to have it available there.
Otherwise, cb_data might be set to the dev in most of the cases.

Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Benjamin Bara <benjamin.bara@skidata.com>
Link: https://lore.kernel.org/r/20230327-tegra-pmic-reboot-v7-3-18699d5dcd76@skidata.com
Signed-off-by: Lee Jones <lee@kernel.org>

Author: benjamin-bara-skidata

include/linux/reboot.h

@@ -129,11 +129,14 @@ enum sys_off_mode {
  * @cb_data: User's callback data.
  * @cmd: Command string. Currently used only by the sys-off restart mode,
  *       NULL otherwise.
+ * @dev: Device of the sys-off handler. Only if known (devm_register_*),
+ *       NULL otherwise.
  */
 struct sys_off_data {
 	int mode;
 	void *cb_data;
 	const char *cmd;
+	struct device *dev;
 };
 
 struct sys_off_handler *

kernel/reboot.c

@@ -55,6 +55,7 @@ struct sys_off_handler {
 	enum sys_off_mode mode;
 	bool blocking;
 	void *list;
+	struct device *dev;
 };
 
 /*
@@ -324,6 +325,7 @@ static int sys_off_notify(struct notifier_block *nb,
 	data.cb_data = handler->cb_data;
 	data.mode = mode;
 	data.cmd = cmd;
+	data.dev = handler->dev;
 
 	return handler->sys_off_cb(&data);
 }
@@ -511,6 +513,7 @@ int devm_register_sys_off_handler(struct device *dev,
 	handler = register_sys_off_handler(mode, priority, callback, cb_data);
 	if (IS_ERR(handler))
 		return PTR_ERR(handler);
+	handler->dev = dev;
 
 	return devm_add_action_or_reset(dev, devm_unregister_sys_off_handler,
 					handler);