Otherwise we try to sleep with preemption disabled, etc.
Noticed by Thomas Gleixner.
Signed-off-by: David S. Miller <davem@davemloft.net>
 
        err = -ENODEV;
 
+       mutex_lock(&of_set_property_mutex);
        write_lock(&devtree_lock);
        prevp = &dp->properties;
        while (*prevp) {
                        void *old_val = prop->value;
                        int ret;
 
-                       mutex_lock(&of_set_property_mutex);
                        ret = prom_setprop(dp->node, name, val, len);
-                       mutex_unlock(&of_set_property_mutex);
 
                        err = -EINVAL;
                        if (ret >= 0) {
                prevp = &(*prevp)->next;
        }
        write_unlock(&devtree_lock);
+       mutex_unlock(&of_set_property_mutex);
 
        /* XXX Upate procfs if necessary... */