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Commit aafe6c2a authored by Eric W. Biederman's avatar Eric W. Biederman Committed by Linus Torvalds
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[PATCH] de_thread: Use tsk not current 



Ingo Oeser pointed out that because current expands to an inline function
it is more space efficient and somewhat faster to simply keep a cached copy
of current in another variable.  This patch implements that for the
de_thread function.

(akpm: saves nearly 100 bytes of text on x86)

Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 66f37509

fs/exec.c

+23 −23
Original line number Diff line number Diff line
@@ -595,7 +595,7 @@ static int de_thread(struct task_struct *tsk) 
	if (!newsighand)

		return -ENOMEM;



	if (thread_group_empty(current))

	if (thread_group_empty(tsk))

		goto no_thread_group;



	/*
@@ -620,17 +620,17 @@ static int de_thread(struct task_struct *tsk) 
	 * Reparenting needs write_lock on tasklist_lock,

	 * so it is safe to do it under read_lock.

	 */

	if (unlikely(current->group_leader == child_reaper))

		child_reaper = current;

	if (unlikely(tsk->group_leader == child_reaper))

		child_reaper = tsk;



	zap_other_threads(current);

	zap_other_threads(tsk);

	read_unlock(&tasklist_lock);



	/*

	 * Account for the thread group leader hanging around:

	 */

	count = 1;

	if (!thread_group_leader(current)) {

	if (!thread_group_leader(tsk)) {

		count = 2;

		/*

		 * The SIGALRM timer survives the exec, but needs to point
@@ -639,14 +639,14 @@ static int de_thread(struct task_struct *tsk) 
		 * synchronize with any firing (by calling del_timer_sync)

		 * before we can safely let the old group leader die.

		 */

		sig->tsk = current;

		sig->tsk = tsk;

		spin_unlock_irq(lock);

		if (hrtimer_cancel(&sig->real_timer))

			hrtimer_restart(&sig->real_timer);

		spin_lock_irq(lock);

	}

	while (atomic_read(&sig->count) > count) {

		sig->group_exit_task = current;

		sig->group_exit_task = tsk;

		sig->notify_count = count;

		__set_current_state(TASK_UNINTERRUPTIBLE);

		spin_unlock_irq(lock);
@@ -662,13 +662,13 @@ static int de_thread(struct task_struct *tsk) 
	 * do is to wait for the thread group leader to become inactive,

	 * and to assume its PID:

	 */

	if (!thread_group_leader(current)) {

	if (!thread_group_leader(tsk)) {

		/*

		 * Wait for the thread group leader to be a zombie.

		 * It should already be zombie at this point, most

		 * of the time.

		 */

		leader = current->group_leader;

		leader = tsk->group_leader;

		while (leader->exit_state != EXIT_ZOMBIE)

			yield();
@@ -682,12 +682,12 @@ static int de_thread(struct task_struct *tsk) 
		 * When we take on its identity by switching to its PID, we

		 * also take its birthdate (always earlier than our own).

		 */

		current->start_time = leader->start_time;

		tsk->start_time = leader->start_time;



		write_lock_irq(&tasklist_lock);



		BUG_ON(leader->tgid != current->tgid);

		BUG_ON(current->pid == current->tgid);

		BUG_ON(leader->tgid != tsk->tgid);

		BUG_ON(tsk->pid == tsk->tgid);

		/*

		 * An exec() starts a new thread group with the

		 * TGID of the previous thread group. Rehash the
@@ -700,17 +700,17 @@ static int de_thread(struct task_struct *tsk) 
		 * Note: The old leader also uses this pid until release_task

		 *       is called.  Odd but simple and correct.

		 */

		detach_pid(current, PIDTYPE_PID);

		current->pid = leader->pid;

		attach_pid(current, PIDTYPE_PID,  current->pid);

		transfer_pid(leader, current, PIDTYPE_PGID);

		transfer_pid(leader, current, PIDTYPE_SID);

		list_replace_rcu(&leader->tasks, &current->tasks);

		detach_pid(tsk, PIDTYPE_PID);

		tsk->pid = leader->pid;

		attach_pid(tsk, PIDTYPE_PID,  tsk->pid);

		transfer_pid(leader, tsk, PIDTYPE_PGID);

		transfer_pid(leader, tsk, PIDTYPE_SID);

		list_replace_rcu(&leader->tasks, &tsk->tasks);



		current->group_leader = current;

		leader->group_leader = current;

		tsk->group_leader = tsk;

		leader->group_leader = tsk;



		current->exit_signal = SIGCHLD;

		tsk->exit_signal = SIGCHLD;



		BUG_ON(leader->exit_state != EXIT_ZOMBIE);

		leader->exit_state = EXIT_DEAD;
@@ -750,7 +750,7 @@ static int de_thread(struct task_struct *tsk) 
		spin_lock(&oldsighand->siglock);

		spin_lock_nested(&newsighand->siglock, SINGLE_DEPTH_NESTING);



		rcu_assign_pointer(current->sighand, newsighand);

		rcu_assign_pointer(tsk->sighand, newsighand);

		recalc_sigpending();



		spin_unlock(&newsighand->siglock);
@@ -761,7 +761,7 @@ static int de_thread(struct task_struct *tsk) 
			kmem_cache_free(sighand_cachep, oldsighand);

	}



	BUG_ON(!thread_group_leader(current));

	BUG_ON(!thread_group_leader(tsk));

	return 0;

}