xen/events: Convert to hotplug state machine

Install the callbacks via the state machine.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

1 files changed, 12 insertions, 22 deletions

diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c
index 266c2c733039..7ef27c6ed72f 100644
--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -418,30 +418,18 @@ static int evtchn_fifo_alloc_control_block(unsigned cpu)
         return ret;
 }
 
-static int evtchn_fifo_cpu_notification(struct notifier_block *self,
-                                                  unsigned long action,
-                                                  void *hcpu)
+static int xen_evtchn_cpu_prepare(unsigned int cpu)
 {
-        int cpu = (long)hcpu;
-        int ret = 0;
-
-        switch (action) {
-        case CPU_UP_PREPARE:
-                if (!per_cpu(cpu_control_block, cpu))
-                        ret = evtchn_fifo_alloc_control_block(cpu);
-                break;
-        case CPU_DEAD:
-                __evtchn_fifo_handle_events(cpu, true);
-                break;
-        default:
-                break;
-        }
-        return ret < 0 ? NOTIFY_BAD : NOTIFY_OK;
+        if (!per_cpu(cpu_control_block, cpu))
+                return evtchn_fifo_alloc_control_block(cpu);
+        return 0;
 }
 
-static struct notifier_block evtchn_fifo_cpu_notifier = {
-        .notifier_call  = evtchn_fifo_cpu_notification,
-};
+static int xen_evtchn_cpu_dead(unsigned int cpu)
+{
+        __evtchn_fifo_handle_events(cpu, true);
+        return 0;
+}
 
 int __init xen_evtchn_fifo_init(void)
 {
@@ -456,7 +444,9 @@ int __init xen_evtchn_fifo_init(void)
 
         evtchn_ops = &evtchn_ops_fifo;
 
-        register_cpu_notifier(&evtchn_fifo_cpu_notifier);
+        cpuhp_setup_state_nocalls(CPUHP_XEN_EVTCHN_PREPARE,
+                                  "CPUHP_XEN_EVTCHN_PREPARE",
+                                  xen_evtchn_cpu_prepare, xen_evtchn_cpu_dead);
 out:
         put_cpu();
         return ret;