export pid symbols needed for kvm_vcpu_on_spin

Export the symbols required for a race-free kvm_vcpu_on_spin.
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

kernel/fork.c

@@ -193,6 +193,7 @@ void __put_task_struct(struct task_struct *tsk)
 	if (!profile_handoff_task(tsk))
 		free_task(tsk);
 }
+EXPORT_SYMBOL_GPL(__put_task_struct);
 
 /*
  * macro override instead of weak attribute alias, to workaround

kernel/pid.c

@@ -435,6 +435,7 @@ struct pid *get_task_pid(struct task_struct *task, enum pid_type type)
 	rcu_read_unlock();
 	return pid;
 }
+EXPORT_SYMBOL_GPL(get_task_pid);
 
 struct task_struct *get_pid_task(struct pid *pid, enum pid_type type)
 {
@@ -446,6 +447,7 @@ struct task_struct *get_pid_task(struct pid *pid, enum pid_type type)
 	rcu_read_unlock();
 	return result;
 }
+EXPORT_SYMBOL_GPL(get_pid_task);
 
 struct pid *find_get_pid(pid_t nr)
 {