From 62c124ff3bcdb414af635c2bf822c9e4f2a5abfa Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 2 Jun 2011 11:14:00 +0200 Subject: ptrace: use bit_waitqueue for TRAPPING instead of wait_chldexit ptracer->signal->wait_chldexit was used to wait for TRAPPING; however, ->wait_chldexit was already complicated with waker-side filtering without adding TRAPPING wait on top of it. Also, it unnecessarily made TRAPPING clearing depend on the current ptrace relationship - if the ptracee is detached, wakeup is lost. There is no reason to use signal->wait_chldexit here. We're just waiting for JOBCTL_TRAPPING bit to clear and given the relatively infrequent use of ptrace, bit_waitqueue can serve it perfectly. This patch makes JOBCTL_TRAPPING wait use bit_waitqueue instead of signal->wait_chldexit. -v2: Use JOBCTL_*_BIT macros instead of ilog2() as suggested by Linus. Signed-off-by: Tejun Heo Cc: Linus Torvalds Signed-off-by: Oleg Nesterov --- kernel/signal.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'kernel/signal.c') diff --git a/kernel/signal.c b/kernel/signal.c index 9ab91c516c3f..172a4c79f12c 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -272,8 +272,7 @@ static void task_clear_jobctl_trapping(struct task_struct *task) { if (unlikely(task->jobctl & JOBCTL_TRAPPING)) { task->jobctl &= ~JOBCTL_TRAPPING; - __wake_up_sync_key(&task->parent->signal->wait_chldexit, - TASK_UNINTERRUPTIBLE, 1, task); + wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT); } } -- cgit v1.2.3