Merge branch 'linus' into pci-for-jesse

1 files changed, 13 insertions, 4 deletions

diff --git a/drivers/s390/char/sclp_config.c b/drivers/s390/char/sclp_config.c
index ad05a87bc48..fff4ff485d9 100644
--- a/drivers/s390/char/sclp_config.c
+++ b/drivers/s390/char/sclp_config.c
@@ -8,6 +8,7 @@
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/cpu.h>
+#include <linux/kthread.h>
 #include <linux/sysdev.h>
 #include <linux/workqueue.h>
 #include <asm/smp.h>
@@ -40,9 +41,19 @@ static void sclp_cpu_capability_notify(struct work_struct *work)
 	put_online_cpus();
 }
 
-static void __ref sclp_cpu_change_notify(struct work_struct *work)
+static int sclp_cpu_kthread(void *data)
 {
 	smp_rescan_cpus();
+	return 0;
+}
+
+static void __ref sclp_cpu_change_notify(struct work_struct *work)
+{
+	/* Can't call smp_rescan_cpus() from  workqueue context since it may
+	 * deadlock in case of cpu hotplug. So we have to create a kernel
+	 * thread in order to call it.
+	 */
+	kthread_run(sclp_cpu_kthread, NULL, "cpu_rescan");
 }
 
 static void sclp_conf_receiver_fn(struct evbuf_header *evbuf)
@@ -74,10 +85,8 @@ static int __init sclp_conf_init(void)
 	INIT_WORK(&sclp_cpu_change_work, sclp_cpu_change_notify);
 
 	rc = sclp_register(&sclp_conf_register);
-	if (rc) {
-		printk(KERN_ERR TAG "failed to register (%d).\n", rc);
+	if (rc)
 		return rc;
-	}
 
 	if (!(sclp_conf_register.sclp_send_mask & EVTYP_CONFMGMDATA_MASK)) {
 		printk(KERN_WARNING TAG "no configuration management.\n");