iommu/vt-d: Convert to hotplug state machine

Install the callbacks via the state machine.

Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: iommu@lists.linux-foundation.org
Cc: rt@linutronix.de
Cc: David Woodhouse <dwmw2@infradead.org>
Link: http://lkml.kernel.org/r/20161126231350.10321-14-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

drivers/iommu/intel-iommu.c

@@ -4665,25 +4665,13 @@ static void free_all_cpu_cached_iovas(unsigned int cpu)
 	}
 }
 
-static int intel_iommu_cpu_notifier(struct notifier_block *nfb,
-				    unsigned long action, void *v)
+static int intel_iommu_cpu_dead(unsigned int cpu)
 {
-	unsigned int cpu = (unsigned long)v;
-
-	switch (action) {
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		free_all_cpu_cached_iovas(cpu);
-		flush_unmaps_timeout(cpu);
-		break;
-	}
-	return NOTIFY_OK;
+	free_all_cpu_cached_iovas(cpu);
+	flush_unmaps_timeout(cpu);
+	return 0;
 }
 
-static struct notifier_block intel_iommu_cpu_nb = {
-	.notifier_call = intel_iommu_cpu_notifier,
-};
-
 static ssize_t intel_iommu_show_version(struct device *dev,
 					struct device_attribute *attr,
 					char *buf)
@@ -4832,8 +4820,8 @@ int __init intel_iommu_init(void)
 	bus_register_notifier(&pci_bus_type, &device_nb);
 	if (si_domain && !hw_pass_through)
 		register_memory_notifier(&intel_iommu_memory_nb);
-	register_hotcpu_notifier(&intel_iommu_cpu_nb);
-
+	cpuhp_setup_state(CPUHP_IOMMU_INTEL_DEAD, "iommu/intel:dead", NULL,
+			  intel_iommu_cpu_dead);
 	intel_iommu_enabled = 1;
 
 	return 0;

include/linux/cpuhotplug.h

@@ -40,6 +40,7 @@ enum cpuhp_state {
 	CPUHP_PAGE_ALLOC_DEAD,
 	CPUHP_NET_DEV_DEAD,
 	CPUHP_PCI_XGENE_DEAD,
+	CPUHP_IOMMU_INTEL_DEAD,
 	CPUHP_WORKQUEUE_PREP,
 	CPUHP_POWER_NUMA_PREPARE,
 	CPUHP_HRTIMERS_PREPARE,