arm64: numa: separate out updates to percpu nodeid and NUMA node cpumap

Currently numa_clear_node removes both cpu information from the NUMA
node cpumap as well as the NUMA node id from the cpu. Similarly
numa_store_cpu_info updates both percpu nodeid and NUMA cpumap.

However we need to retain the numa node id for the cpu and only remove
the cpu information from the numa node cpumap during CPU hotplug out.
The same can be extended for hotplugging in the CPU.

This patch separates out numa_{add,remove}_cpu from numa_clear_node and
numa_store_cpu_info.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Reviewed-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
Tested-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c
index dad128b..146c04c 100644
--- a/arch/arm64/mm/numa.c
+++ b/arch/arm64/mm/numa.c
@@ -70,19 +70,32 @@ EXPORT_SYMBOL(cpumask_of_node);
 
 #endif
 
-static void map_cpu_to_node(unsigned int cpu, int nid)
+static void numa_update_cpu(unsigned int cpu, bool remove)
 {
-	set_cpu_numa_node(cpu, nid);
-	if (nid >= 0)
+	int nid = cpu_to_node(cpu);
+
+	if (nid == NUMA_NO_NODE)
+		return;
+
+	if (remove)
+		cpumask_clear_cpu(cpu, node_to_cpumask_map[nid]);
+	else
 		cpumask_set_cpu(cpu, node_to_cpumask_map[nid]);
 }
 
+void numa_add_cpu(unsigned int cpu)
+{
+	numa_update_cpu(cpu, false);
+}
+
+void numa_remove_cpu(unsigned int cpu)
+{
+	numa_update_cpu(cpu, true);
+}
+
 void numa_clear_node(unsigned int cpu)
 {
-	int nid = cpu_to_node(cpu);
-
-	if (nid >= 0)
-		cpumask_clear_cpu(cpu, node_to_cpumask_map[nid]);
+	numa_remove_cpu(cpu);
 	set_cpu_numa_node(cpu, NUMA_NO_NODE);
 }
 
@@ -116,7 +129,7 @@ static void __init setup_node_to_cpumask_map(void)
  */
 void numa_store_cpu_info(unsigned int cpu)
 {
-	map_cpu_to_node(cpu, cpu_to_node_map[cpu]);
+	set_cpu_numa_node(cpu, cpu_to_node_map[cpu]);
 }
 
 void __init early_map_cpu_to_node(unsigned int cpu, int nid)