1 files changed, 31 insertions, 4 deletions

diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c
index 12b39b3d9c38..661a07217057 100644
--- a/arch/s390/kernel/topology.c
+++ b/arch/s390/kernel/topology.c
@@ -9,6 +9,7 @@
 #include <linux/device.h>
 #include <linux/bootmem.h>
 #include <linux/sched.h>
+#include <linux/kthread.h>
 #include <linux/workqueue.h>
 #include <linux/cpu.h>
 #include <linux/smp.h>
@@ -66,6 +67,8 @@ static struct timer_list topology_timer;
 static void set_topology_timer(void);
 static DECLARE_WORK(topology_work, topology_work_fn);
 
+cpumask_t cpu_core_map[NR_CPUS];
+
 cpumask_t cpu_coregroup_map(unsigned int cpu)
 {
         struct core_info *core = &core_info;
@@ -199,6 +202,14 @@ int topology_set_cpu_management(int fc)
         return rc;
 }
 
+static void update_cpu_core_map(void)
+{
+        int cpu;
+
+        for_each_present_cpu(cpu)
+                cpu_core_map[cpu] = cpu_coregroup_map(cpu);
+}
+
 void arch_update_cpu_topology(void)
 {
         struct tl_info *info = tl_info;
@@ -206,20 +217,33 @@ void arch_update_cpu_topology(void)
         int cpu;
 
         if (!machine_has_topology) {
+                update_cpu_core_map();
                 topology_update_polarization_simple();
                 return;
         }
         stsi(info, 15, 1, 2);
         tl_to_cores(info);
+        update_cpu_core_map();
         for_each_online_cpu(cpu) {
                 sysdev = get_cpu_sysdev(cpu);
                 kobject_uevent(&sysdev->kobj, KOBJ_CHANGE);
         }
 }
 
-static void topology_work_fn(struct work_struct *work)
+static int topology_kthread(void *data)
 {
         arch_reinit_sched_domains();
+        return 0;
+}
+
+static void topology_work_fn(struct work_struct *work)
+{
+        /* We can't call arch_reinit_sched_domains() from a multi-threaded
+         * workqueue context since it may deadlock in case of cpu hotplug.
+         * So we have to create a kernel thread in order to call
+         * arch_reinit_sched_domains().
+         */
+        kthread_run(topology_kthread, NULL, "topology_update");
 }
 
 void topology_schedule_update(void)
@@ -251,20 +275,23 @@ static int __init init_topology_update(void)
 {
         int rc;
 
+        rc = 0;
         if (!machine_has_topology) {
                 topology_update_polarization_simple();
-                return 0;
+                goto out;
         }
         init_timer_deferrable(&topology_timer);
         if (machine_has_topology_irq) {
                 rc = register_external_interrupt(0x2005, topology_interrupt);
                 if (rc)
-                        return rc;
+                        goto out;
                 ctl_set_bit(0, 8);
         }
         else
                 set_topology_timer();
-        return 0;
+out:
+        update_cpu_core_map();
+        return rc;
 }
 __initcall(init_topology_update);