提交 dac27f4a 编写于 作者: O Oleg Nesterov 提交者: Linus Torvalds

[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: NOleg Nesterov <oleg@tv-sign.ru>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
上级 a7e5328a
......@@ -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;
}
spin_unlock_irq(&sighand->siglock);
if (stop_count == 0)
sig->flags = SIGNAL_STOP_STOPPED;
current->exit_code = sig->group_exit_code;
__set_current_state(TASK_STOPPED);
spin_unlock_irq(&current->sighand->siglock);
finish_stop(stop_count);
return 1;
}
......
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