[S390] cpu topology: Fix possible deadlock.

[linux-2.6-omap-h63xx.git] / arch / s390 / kernel / topology.c

diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c
index 0becefcf19b97750f880237831570ae159ff259f..661a07217057a37b8d08b7ad85c8d4a2508a2bd0 100644 (file)
--- 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>
@@ -229,9 +230,20 @@ void arch_update_cpu_topology(void)
        }
 }
 
-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)