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Commit dac27f4a authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

[PATCH] simplify do_signal_stop() 



do_signal_stop() considers 'thread_group_empty()' as a special case.
This was needed to avoid taking tasklist_lock. Since this lock is
unneeded any longer, we can remove this special case and simplify
the code even more.

Also, before this patch, finish_stop() was called with stop_count == -1
for 'thread_group_empty()' case. This is not strictly wrong, but confusing
and unneeded.

Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent a7e5328a

kernel/signal.c

+8 −24
Original line number Diff line number Diff line
@@ -1685,8 +1685,7 @@ finish_stop(int stop_count) 
static int do_signal_stop(int signr)

{

	struct signal_struct *sig = current->signal;

	struct sighand_struct *sighand = current->sighand;

	int stop_count = -1;

	int stop_count;



	if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED))

		return 0;
@@ -1696,30 +1695,14 @@ static int do_signal_stop(int signr) 
		 * There is a group stop in progress.  We don't need to

		 * start another one.

		 */

		signr = sig->group_exit_code;

		stop_count = --sig->group_stop_count;

		current->exit_code = signr;

		set_current_state(TASK_STOPPED);

		if (stop_count == 0)

			sig->flags = SIGNAL_STOP_STOPPED;

	}

	else if (thread_group_empty(current)) {

		/*

		 * Lock must be held through transition to stopped state.

		 */

		current->exit_code = current->signal->group_exit_code = signr;

		set_current_state(TASK_STOPPED);

		sig->flags = SIGNAL_STOP_STOPPED;

	}

	else {

	} else {

		/*

		 * (sig->group_stop_count == 0)

		 * There is no group stop already in progress.

		 * We must initiate one now.

		 */

		struct task_struct *t;



		current->exit_code = signr;

		sig->group_exit_code = signr;



		stop_count = 0;
@@ -1735,13 +1718,14 @@ static int do_signal_stop(int signr) 
				signal_wake_up(t, 0);

			}

		sig->group_stop_count = stop_count;

	}



		set_current_state(TASK_STOPPED);

	if (stop_count == 0)

		sig->flags = SIGNAL_STOP_STOPPED;

	}

	current->exit_code = sig->group_exit_code;

	__set_current_state(TASK_STOPPED);



	spin_unlock_irq(&sighand->siglock);

	spin_unlock_irq(&current->sighand->siglock);

	finish_stop(stop_count);

	return 1;

}