From: Oleg Nesterov Date: Wed, 30 Apr 2008 07:53:04 +0000 (-0700) Subject: signals: de_thread: simplify the ->child_reaper switching X-Git-Tag: upstream/snapshot3+hdmi~25440 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=7a5e873f096e04e6d8719e4ecb7b70d2decca503;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git signals: de_thread: simplify the ->child_reaper switching Now that we rely on SIGNAL_UNKILLABLE flag, de_thread() doesn't need the nasty hack to kill the old ->child_reaper during the mt-exec. This also means we can avoid taking tasklist_lock around zap_other_threads(). Signed-off-by: Oleg Nesterov Cc: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/exec.c b/fs/exec.c index a138839..8fccc27 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -766,9 +766,7 @@ static int de_thread(struct task_struct *tsk) /* * Kill all other threads in the thread group. - * We must hold tasklist_lock to call zap_other_threads. */ - read_lock(&tasklist_lock); spin_lock_irq(lock); if (signal_group_exit(sig)) { /* @@ -776,21 +774,10 @@ static int de_thread(struct task_struct *tsk) * return so that the signal is processed. */ spin_unlock_irq(lock); - read_unlock(&tasklist_lock); return -EAGAIN; } - - /* - * child_reaper ignores SIGKILL, change it now. - * Reparenting needs write_lock on tasklist_lock, - * so it is safe to do it under read_lock. - */ - if (unlikely(tsk->group_leader == task_child_reaper(tsk))) - task_active_pid_ns(tsk)->child_reaper = tsk; - sig->group_exit_task = tsk; zap_other_threads(tsk); - read_unlock(&tasklist_lock); /* Account for the thread group leader hanging around: */ count = thread_group_leader(tsk) ? 1 : 2; @@ -821,6 +808,8 @@ static int de_thread(struct task_struct *tsk) schedule(); } + if (unlikely(task_child_reaper(tsk) == leader)) + task_active_pid_ns(tsk)->child_reaper = tsk; /* * The only record we have of the real-time age of a * process, regardless of execs it's done, is start_time.