[S390] appldata: prevent cpu hotplug when walking cpu_online_map.

Use get_online_cpus() to prevent cpu hotplug in situations where
for_each_online_cpu() is called.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/appldata/appldata_base.c b/arch/s390/appldata/appldata_base.c
index 655d525..ad40729 100644 (file)
--- a/arch/s390/appldata/appldata_base.c
+++ b/arch/s390/appldata/appldata_base.c
@@ -130,6 +130,7 @@ static void appldata_work_fn(struct work_struct *work)
 
        P_DEBUG("  -= Work Queue =-\n");
        i = 0;
+       get_online_cpus();
        spin_lock(&appldata_ops_lock);
        list_for_each(lh, &appldata_ops_list) {
                ops = list_entry(lh, struct appldata_ops, list);
@@ -140,6 +141,7 @@ static void appldata_work_fn(struct work_struct *work)
                }
        }
        spin_unlock(&appldata_ops_lock);
+       put_online_cpus();
 }
 
 /*
@@ -266,12 +268,14 @@ appldata_timer_handler(ctl_table *ctl, int write, struct file *filp,
        len = *lenp;
        if (copy_from_user(buf, buffer, len > sizeof(buf) ? sizeof(buf) : len))
                return -EFAULT;
+       get_online_cpus();
        spin_lock(&appldata_timer_lock);
        if (buf[0] == '1')
                __appldata_vtimer_setup(APPLDATA_ADD_TIMER);
        else if (buf[0] == '0')
                __appldata_vtimer_setup(APPLDATA_DEL_TIMER);
        spin_unlock(&appldata_timer_lock);
+       put_online_cpus();
 out:
        *lenp = len;
        *ppos += len;
@@ -314,10 +318,12 @@ appldata_interval_handler(ctl_table *ctl, int write, struct file *filp,
                return -EINVAL;
        }
 
+       get_online_cpus();
        spin_lock(&appldata_timer_lock);
        appldata_interval = interval;
        __appldata_vtimer_setup(APPLDATA_MOD_TIMER);
        spin_unlock(&appldata_timer_lock);
+       put_online_cpus();
 
        P_INFO("Monitoring CPU interval set to %u milliseconds.\n",
                 interval);
@@ -556,8 +562,10 @@ static int __init appldata_init(void)
                return -ENOMEM;
        }
 
+       get_online_cpus();
        for_each_online_cpu(i)
                appldata_online_cpu(i);
+       put_online_cpus();
 
        /* Register cpu hotplug notifier */
        register_hotcpu_notifier(&appldata_nb);