iucv: prevent cpu hotplug when walking cpu_online_map.

The code used preempt_disable() to prevent cpu hotplug, however that
doesn't protect for cpus being added. So use get_online_cpus() instead.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Ursula Braun <braunu@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/iucv/iucv.c b/net/iucv/iucv.c
index 2d43175..531a206 100644 (file)
--- a/net/iucv/iucv.c
+++ b/net/iucv/iucv.c
@@ -474,14 +474,14 @@ static void iucv_setmask_mp(void)
 {
        int cpu;
 
-       preempt_disable();
+       get_online_cpus();
        for_each_online_cpu(cpu)
                /* Enable all cpus with a declared buffer. */
                if (cpu_isset(cpu, iucv_buffer_cpumask) &&
                    !cpu_isset(cpu, iucv_irq_cpumask))
                        smp_call_function_single(cpu, iucv_allow_cpu,
                                                 NULL, 0, 1);
-       preempt_enable();
+       put_online_cpus();
 }
 
 /**
@@ -521,16 +521,17 @@ static int iucv_enable(void)
                goto out;
        /* Declare per cpu buffers. */
        rc = -EIO;
-       preempt_disable();
+       get_online_cpus();
        for_each_online_cpu(cpu)
                smp_call_function_single(cpu, iucv_declare_cpu, NULL, 0, 1);
-       preempt_enable();
        if (cpus_empty(iucv_buffer_cpumask))
                /* No cpu could declare an iucv buffer. */
                goto out_path;
+       put_online_cpus();
        return 0;
 
 out_path:
+       put_online_cpus();
        kfree(iucv_path_table);
 out:
        return rc;
@@ -545,7 +546,9 @@ out:
  */
 static void iucv_disable(void)
 {
+       get_online_cpus();
        on_each_cpu(iucv_retrieve_cpu, NULL, 0, 1);
+       put_online_cpus();
        kfree(iucv_path_table);
 }