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

[linux-2.6-omap-h63xx.git] / arch / s390 / appldata / appldata_base.c

diff --git a/arch/s390/appldata/appldata_base.c b/arch/s390/appldata/appldata_base.c
index ac61cf43a7d950b36cf1316165ea499c63c6283d..ad40729bec3d9a062925b2b2db3bf7d990d0ea3e 100644 (file)
--- a/arch/s390/appldata/appldata_base.c
+++ b/arch/s390/appldata/appldata_base.c
@@ -53,29 +53,26 @@ static int appldata_interval_handler(ctl_table *ctl, int write,
 static struct ctl_table_header *appldata_sysctl_header;
 static struct ctl_table appldata_table[] = {
        {
-               .ctl_name       = CTL_APPLDATA_TIMER,
                .procname       = "timer",
                .mode           = S_IRUGO | S_IWUSR,
                .proc_handler   = &appldata_timer_handler,
        },
        {
-               .ctl_name       = CTL_APPLDATA_INTERVAL,
                .procname       = "interval",
                .mode           = S_IRUGO | S_IWUSR,
                .proc_handler   = &appldata_interval_handler,
        },
-       { .ctl_name = 0 }
+       { },
 };
 
 static struct ctl_table appldata_dir_table[] = {
        {
-               .ctl_name       = CTL_APPLDATA,
                .procname       = appldata_proc_name,
                .maxlen         = 0,
                .mode           = S_IRUGO | S_IXUGO,
                .child          = appldata_table,
        },
-       { .ctl_name = 0 }
+       { },
 };
 
 /*
@@ -133,6 +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);
@@ -143,6 +141,7 @@ static void appldata_work_fn(struct work_struct *work)
                }
        }
        spin_unlock(&appldata_ops_lock);
+       put_online_cpus();
 }
 
 /*
@@ -269,12 +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;
@@ -317,10 +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);
@@ -441,75 +444,38 @@ out:
  */
 int appldata_register_ops(struct appldata_ops *ops)
 {
-       struct list_head *lh;
-       struct appldata_ops *tmp_ops;
-       int i;
-
-       i = 0;
+       if ((ops->size > APPLDATA_MAX_REC_SIZE) || (ops->size < 0))
+               return -EINVAL;
 
-       if ((ops->size > APPLDATA_MAX_REC_SIZE) ||
-               (ops->size < 0)){
-               P_ERROR("Invalid size of %s record = %i, maximum = %i!\n",
-                       ops->name, ops->size, APPLDATA_MAX_REC_SIZE);
-               return -ENOMEM;
-       }
-       if ((ops->ctl_nr == CTL_APPLDATA) ||
-           (ops->ctl_nr == CTL_APPLDATA_TIMER) ||
-           (ops->ctl_nr == CTL_APPLDATA_INTERVAL)) {
-               P_ERROR("ctl_nr %i already in use!\n", ops->ctl_nr);
-               return -EBUSY;
-       }
-       ops->ctl_table = kzalloc(4*sizeof(struct ctl_table), GFP_KERNEL);
-       if (ops->ctl_table == NULL) {
-               P_ERROR("Not enough memory for %s ctl_table!\n", ops->name);
+       ops->ctl_table = kzalloc(4 * sizeof(struct ctl_table), GFP_KERNEL);
+       if (!ops->ctl_table)
                return -ENOMEM;
-       }
 
        spin_lock(&appldata_ops_lock);
-       list_for_each(lh, &appldata_ops_list) {
-               tmp_ops = list_entry(lh, struct appldata_ops, list);
-               P_DEBUG("register_ops loop: %i) name = %s, ctl = %i\n",
-                       ++i, tmp_ops->name, tmp_ops->ctl_nr);
-               P_DEBUG("Comparing %s (ctl %i) with %s (ctl %i)\n",
-                       tmp_ops->name, tmp_ops->ctl_nr, ops->name,
-                       ops->ctl_nr);
-               if (strncmp(tmp_ops->name, ops->name,
-                               APPLDATA_PROC_NAME_LENGTH) == 0) {
-                       P_ERROR("Name \"%s\" already registered!\n", ops->name);
-                       kfree(ops->ctl_table);
-                       spin_unlock(&appldata_ops_lock);
-                       return -EBUSY;
-               }
-               if (tmp_ops->ctl_nr == ops->ctl_nr) {
-                       P_ERROR("ctl_nr %i already registered!\n", ops->ctl_nr);
-                       kfree(ops->ctl_table);
-                       spin_unlock(&appldata_ops_lock);
-                       return -EBUSY;
-               }
-       }
        list_add(&ops->list, &appldata_ops_list);
        spin_unlock(&appldata_ops_lock);
 
-       ops->ctl_table[0].ctl_name = CTL_APPLDATA;
        ops->ctl_table[0].procname = appldata_proc_name;
        ops->ctl_table[0].maxlen   = 0;
        ops->ctl_table[0].mode     = S_IRUGO | S_IXUGO;
        ops->ctl_table[0].child    = &ops->ctl_table[2];
 
-       ops->ctl_table[1].ctl_name = 0;
-
-       ops->ctl_table[2].ctl_name = ops->ctl_nr;
        ops->ctl_table[2].procname = ops->name;
        ops->ctl_table[2].mode     = S_IRUGO | S_IWUSR;
        ops->ctl_table[2].proc_handler = appldata_generic_handler;
        ops->ctl_table[2].data = ops;
 
-       ops->ctl_table[3].ctl_name = 0;
-
        ops->sysctl_header = register_sysctl_table(ops->ctl_table);
-
+       if (!ops->sysctl_header)
+               goto out;
        P_INFO("%s-ops registered!\n", ops->name);
        return 0;
+out:
+       spin_lock(&appldata_ops_lock);
+       list_del(&ops->list);
+       spin_unlock(&appldata_ops_lock);
+       kfree(ops->ctl_table);
+       return -ENOMEM;
 }
 
 /*
@@ -519,15 +485,11 @@ int appldata_register_ops(struct appldata_ops *ops)
  */
 void appldata_unregister_ops(struct appldata_ops *ops)
 {
-       void *table;
        spin_lock(&appldata_ops_lock);
        list_del(&ops->list);
-       /* at that point any incoming access will fail */
-       table = ops->ctl_table;
-       ops->ctl_table = NULL;
        spin_unlock(&appldata_ops_lock);
        unregister_sysctl_table(ops->sysctl_header);
-       kfree(table);
+       kfree(ops->ctl_table);
        P_INFO("%s-ops unregistered!\n", ops->name);
 }
 /********************** module-ops management <END> **************************/
@@ -600,8 +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);