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

Pull CPU hotplug updates from Thomas Gleixner:
 "Yet another batch of cpu hotplug core updates and conversions:

   - Provide core infrastructure for multi instance drivers so the
     drivers do not have to keep custom lists.

   - Convert custom lists to the new infrastructure. The block-mq custom
     list conversion comes through the block tree and makes the diffstat
     tip over to more lines removed than added.

   - Handle unbalanced hotplug enable/disable calls more gracefully.

   - Remove the obsolete CPU_STARTING/DYING notifier support.

   - Convert another batch of notifier users.

   The relayfs changes which conflicted with the conversion have been
   shipped to me by Andrew.

   The remaining lot is targeted for 4.10 so that we finally can remove
   the rest of the notifiers"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (46 commits)
  cpufreq: Fix up conversion to hotplug state machine
  blk/mq: Reserve hotplug states for block multiqueue
  x86/apic/uv: Convert to hotplug state machine
  s390/mm/pfault: Convert to hotplug state machine
  mips/loongson/smp: Convert to hotplug state machine
  mips/octeon/smp: Convert to hotplug state machine
  fault-injection/cpu: Convert to hotplug state machine
  padata: Convert to hotplug state machine
  cpufreq: Convert to hotplug state machine
  ACPI/processor: Convert to hotplug state machine
  virtio scsi: Convert to hotplug state machine
  oprofile/timer: Convert to hotplug state machine
  block/softirq: Convert to hotplug state machine
  lib/irq_poll: Convert to hotplug state machine
  x86/microcode: Convert to hotplug state machine
  sh/SH-X3 SMP: Convert to hotplug state machine
  ia64/mca: Convert to hotplug state machine
  ARM/OMAP/wakeupgen: Convert to hotplug state machine
  ARM/shmobile: Convert to hotplug state machine
  arm64/FP/SIMD: Convert to hotplug state machine
  ...

1 files changed, 18 insertions, 26 deletions

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 30370817bf13..b37b57294566 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -709,28 +709,20 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
 	return 0;
 }
 
-static DEFINE_SPINLOCK(arm_pmu_lock);
-static LIST_HEAD(arm_pmu_list);
-
 /*
  * PMU hardware loses all context when a CPU goes offline.
  * When a CPU is hotplugged back in, since some hardware registers are
  * UNKNOWN at reset, the PMU must be explicitly reset to avoid reading
  * junk values out of them.
  */
-static int arm_perf_starting_cpu(unsigned int cpu)
+static int arm_perf_starting_cpu(unsigned int cpu, struct hlist_node *node)
 {
-	struct arm_pmu *pmu;
-
-	spin_lock(&arm_pmu_lock);
-	list_for_each_entry(pmu, &arm_pmu_list, entry) {
+	struct arm_pmu *pmu = hlist_entry_safe(node, struct arm_pmu, node);
 
-		if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
-			continue;
-		if (pmu->reset)
-			pmu->reset(pmu);
-	}
-	spin_unlock(&arm_pmu_lock);
+	if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
+		return 0;
+	if (pmu->reset)
+		pmu->reset(pmu);
 	return 0;
 }
 
@@ -842,9 +834,10 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
 	if (!cpu_hw_events)
 		return -ENOMEM;
 
-	spin_lock(&arm_pmu_lock);
-	list_add_tail(&cpu_pmu->entry, &arm_pmu_list);
-	spin_unlock(&arm_pmu_lock);
+	err = cpuhp_state_add_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
+					       &cpu_pmu->node);
+	if (err)
+		goto out_free;
 
 	err = cpu_pm_pmu_register(cpu_pmu);
 	if (err)
@@ -880,9 +873,9 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
 	return 0;
 
 out_unregister:
-	spin_lock(&arm_pmu_lock);
-	list_del(&cpu_pmu->entry);
-	spin_unlock(&arm_pmu_lock);
+	cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
+					    &cpu_pmu->node);
+out_free:
 	free_percpu(cpu_hw_events);
 	return err;
 }
@@ -890,9 +883,8 @@ out_unregister:
 static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu)
 {
 	cpu_pm_pmu_unregister(cpu_pmu);
-	spin_lock(&arm_pmu_lock);
-	list_del(&cpu_pmu->entry);
-	spin_unlock(&arm_pmu_lock);
+	cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
+					    &cpu_pmu->node);
 	free_percpu(cpu_pmu->hw_events);
 }
 
@@ -1091,9 +1083,9 @@ static int arm_pmu_hp_init(void)
 {
 	int ret;
 
-	ret = cpuhp_setup_state_nocalls(CPUHP_AP_PERF_ARM_STARTING,
-					"AP_PERF_ARM_STARTING",
-					arm_perf_starting_cpu, NULL);
+	ret = cpuhp_setup_state_multi(CPUHP_AP_PERF_ARM_STARTING,
+				      "AP_PERF_ARM_STARTING",
+				      arm_perf_starting_cpu, NULL);
 	if (ret)
 		pr_err("CPU hotplug notifier for ARM PMU could not be registered: %d\n",
 		       ret);