kthread: Don't looking for a task in create_kthread() #2

Remove the unnecessary find_task_by_pid_ns(). kthread() can just
use "current" to get the same result.
Signed-off-by: Vitaliy Gusev <vgusev@openvz.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

kernel/kthread.c

@@ -76,6 +76,7 @@ static int kthread(void *_create)
 
 	/* OK, tell user we're spawned, wait for stop or wakeup */
 	__set_current_state(TASK_UNINTERRUPTIBLE);
+	create->result = current;
 	complete(&create->started);
 	schedule();
 
@@ -101,9 +102,6 @@ static void create_kthread(struct kthread_create_info *create)
 	} else {
 		struct sched_param param = { .sched_priority = 0 };
 		wait_for_completion(&create->started);
-		read_lock(&tasklist_lock);
-		create->result = find_task_by_pid_ns(pid, &init_pid_ns);
-		read_unlock(&tasklist_lock);
 		/*
 		 * root may have changed our (kthreadd's) priority or CPU mask.
 		 * The kernel thread should not inherit these properties.