[PATCH v5 31/48] x86: apm: Register with kernel power-off handler

[Guenter Roeck <linux@roeck-us.net>]

Register with kernel power-off handler instead of setting pm_power_off
directly. Register with high priority to reflect that the original code
overwrites existing power-off handlers.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v5:
- Rebase to v3.18-rc3
v4:
- Do not use notifiers but internal functions and data structures to manage
  the list of power-off handlers. Drop unused parameters from callbacks, and
  make the power-off function type void
v3:
- Replace poweroff in all newly introduced variables and in text
  with power_off or power-off as appropriate
- Replace POWEROFF_PRIORITY_xxx with POWER_OFF_PRIORITY_xxx
v2:
- Use define to specify poweroff handler priority

 arch/x86/kernel/apm_32.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/apm_32.c b/arch/x86/kernel/apm_32.c
index 5848744..04910de 100644
--- a/arch/x86/kernel/apm_32.c
+++ b/arch/x86/kernel/apm_32.c
@@ -981,7 +981,7 @@ recalc:
  *	on their first cpu.
  */
 
-static void apm_power_off(void)
+static void apm_power_off(struct power_off_handler_block *this)
 {
 	/* Some bioses don't like being called from CPU != 0 */
 	if (apm_info.realmode_power_off) {
@@ -992,6 +992,11 @@ static void apm_power_off(void)
 	}
 }
 
+static struct power_off_handler_block apm_power_off_hb = {
+	.handler = apm_power_off,
+	.priority = POWER_OFF_PRIORITY_HIGH,
+};
+
 #ifdef CONFIG_APM_DO_ENABLE
 
 /**
@@ -1847,8 +1852,11 @@ static int apm(void *unused)
 	}
 
 	/* Install our power off handler.. */
-	if (power_off)
-		pm_power_off = apm_power_off;
+	if (power_off) {
+		error = register_power_off_handler(&apm_power_off_hb);
+		if (error)
+			pr_warn("apm: Failed to register power-off handler\n");
+	}
 
 	if (num_online_cpus() == 1 || smp) {
 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
@@ -2408,9 +2416,8 @@ static void __exit apm_exit(void)
 			apm_error("disengage power management", error);
 	}
 	misc_deregister(&apm_device);
+	unregister_power_off_handler(&apm_power_off_hb);
 	remove_proc_entry("apm", NULL);
-	if (power_off)
-		pm_power_off = NULL;
 	if (kapmd_task) {
 		kthread_stop(kapmd_task);
 		kapmd_task = NULL;
-- 
1.9.1