Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull smp hotplug updates from Thomas Gleixner:
 "This is the final round of converting the notifier mess to the state
  machine. The removal of the notifiers and the related infrastructure
  will happen around rc1, as there are conversions outstanding in other
  trees.

  The whole exercise removed about 2000 lines of code in total and in
  course of the conversion several dozen bugs got fixed. The new
  mechanism allows to test almost every hotplug step standalone, so
  usage sites can exercise all transitions extensively.

  There is more room for improvement, like integrating all the
  pointlessly different architecture mechanisms of synchronizing,
  setting cpus online etc into the core code"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits)
  tracing/rb: Init the CPU mask on allocation
  soc/fsl/qbman: Convert to hotplug state machine
  soc/fsl/qbman: Convert to hotplug state machine
  zram: Convert to hotplug state machine
  KVM/PPC/Book3S HV: Convert to hotplug state machine
  arm64/cpuinfo: Convert to hotplug state machine
  arm64/cpuinfo: Make hotplug notifier symmetric
  mm/compaction: Convert to hotplug state machine
  iommu/vt-d: Convert to hotplug state machine
  mm/zswap: Convert pool to hotplug state machine
  mm/zswap: Convert dst-mem to hotplug state machine
  mm/zsmalloc: Convert to hotplug state machine
  mm/vmstat: Convert to hotplug state machine
  mm/vmstat: Avoid on each online CPU loops
  mm/vmstat: Drop get_online_cpus() from init_cpu_node_state/vmstat_cpu_dead()
  tracing/rb: Convert to hotplug state machine
  oprofile/nmi timer: Convert to hotplug state machine
  net/iucv: Use explicit clean up labels in iucv_init()
  x86/pci/amd-bus: Convert to hotplug state machine
  x86/oprofile/nmi: Convert to hotplug state machine
  ...

1 files changed, 9 insertions, 36 deletions

diff --git a/arch/sparc/kernel/sysfs.c b/arch/sparc/kernel/sysfs.c
index fa8e21abb5e0..4808b6d23455 100644
--- a/arch/sparc/kernel/sysfs.c
+++ b/arch/sparc/kernel/sysfs.c
@@ -221,7 +221,7 @@ static struct device_attribute cpu_core_attrs[] = {
 
 static DEFINE_PER_CPU(struct cpu, cpu_devices);
 
-static void register_cpu_online(unsigned int cpu)
+static int register_cpu_online(unsigned int cpu)
 {
 	struct cpu *c = &per_cpu(cpu_devices, cpu);
 	struct device *s = &c->dev;
@@ -231,11 +231,12 @@ static void register_cpu_online(unsigned int cpu)
 		device_create_file(s, &cpu_core_attrs[i]);
 
 	register_mmu_stats(s);
+	return 0;
 }
 
-#ifdef CONFIG_HOTPLUG_CPU
-static void unregister_cpu_online(unsigned int cpu)
+static int unregister_cpu_online(unsigned int cpu)
 {
+#ifdef CONFIG_HOTPLUG_CPU
 	struct cpu *c = &per_cpu(cpu_devices, cpu);
 	struct device *s = &c->dev;
 	int i;
@@ -243,33 +244,10 @@ static void unregister_cpu_online(unsigned int cpu)
 	unregister_mmu_stats(s);
 	for (i = 0; i < ARRAY_SIZE(cpu_core_attrs); i++)
 		device_remove_file(s, &cpu_core_attrs[i]);
-}
-#endif
-
-static int sysfs_cpu_notify(struct notifier_block *self,
-				      unsigned long action, void *hcpu)
-{
-	unsigned int cpu = (unsigned int)(long)hcpu;
-
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		register_cpu_online(cpu);
-		break;
-#ifdef CONFIG_HOTPLUG_CPU
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		unregister_cpu_online(cpu);
-		break;
 #endif
-	}
-	return NOTIFY_OK;
+	return 0;
 }
 
-static struct notifier_block sysfs_cpu_nb = {
-	.notifier_call	= sysfs_cpu_notify,
-};
-
 static void __init check_mmu_stats(void)
 {
 	unsigned long dummy1, err;
@@ -294,26 +272,21 @@ static void register_nodes(void)
 
 static int __init topology_init(void)
 {
-	int cpu;
+	int cpu, ret;
 
 	register_nodes();
 
 	check_mmu_stats();
 
-	cpu_notifier_register_begin();
-
 	for_each_possible_cpu(cpu) {
 		struct cpu *c = &per_cpu(cpu_devices, cpu);
 
 		register_cpu(c, cpu);
-		if (cpu_online(cpu))
-			register_cpu_online(cpu);
 	}
 
-	__register_cpu_notifier(&sysfs_cpu_nb);
-
-	cpu_notifier_register_done();
-
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "sparc/topology:online",
+				register_cpu_online, unregister_cpu_online);
+	WARN_ON(ret < 0);
 	return 0;
 }