From: Oleg Nesterov Date: Wed, 30 Apr 2008 07:53:11 +0000 (-0700) Subject: ptrace: introduce task_detached() helper X-Git-Tag: v2.6.26-rc1~267 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d839fd4d2e95a5fbc4d50aa9d17eed6a5f2094e6;p=linux-2.6 ptrace: introduce task_detached() helper exit.c has numerous "->exit_signal == -1" comparisons, this check is subtle and deserves a helper. Imho makes the code more parseable for humans. At least it's surely more greppable. Also, a couple of whitespace cleanups. No functional changes. Signed-off-by: Oleg Nesterov Cc: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/kernel/exit.c b/kernel/exit.c index 6d019aa852..4035d391a0 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -52,6 +52,11 @@ static void exit_mm(struct task_struct * tsk); +static inline int task_detached(struct task_struct *p) +{ + return p->exit_signal == -1; +} + static void __unhash_process(struct task_struct *p) { nr_threads--; @@ -160,7 +165,7 @@ repeat: zap_leader = 0; leader = p->group_leader; if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) { - BUG_ON(leader->exit_signal == -1); + BUG_ON(task_detached(leader)); do_notify_parent(leader, leader->exit_signal); /* * If we were the last child thread and the leader has @@ -170,7 +175,7 @@ repeat: * do_notify_parent() will have marked it self-reaping in * that case. */ - zap_leader = (leader->exit_signal == -1); + zap_leader = task_detached(leader); } write_unlock_irq(&tasklist_lock); @@ -721,14 +726,14 @@ reparent_thread(struct task_struct *p, struct task_struct *father, int traced) return; /* We don't want people slaying init. */ - if (p->exit_signal != -1) + if (!task_detached(p)) p->exit_signal = SIGCHLD; /* If we'd notified the old parent about this child's death, * also notify the new parent. */ if (!traced && p->exit_state == EXIT_ZOMBIE && - p->exit_signal != -1 && thread_group_empty(p)) + !task_detached(p) && thread_group_empty(p)) do_notify_parent(p, p->exit_signal); kill_orphaned_pgrp(p, father); @@ -781,18 +786,18 @@ static void forget_original_parent(struct task_struct *father) } else { /* reparent ptraced task to its real parent */ __ptrace_unlink (p); - if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 && + if (p->exit_state == EXIT_ZOMBIE && !task_detached(p) && thread_group_empty(p)) do_notify_parent(p, p->exit_signal); } /* - * if the ptraced child is a zombie with exit_signal == -1 - * we must collect it before we exit, or it will remain - * zombie forever since we prevented it from self-reap itself - * while it was being traced by us, to be able to see it in wait4. + * if the ptraced child is a detached zombie we must collect + * it before we exit, or it will remain zombie forever since + * we prevented it from self-reap itself while it was being + * traced by us, to be able to see it in wait4. */ - if (unlikely(ptrace && p->exit_state == EXIT_ZOMBIE && p->exit_signal == -1)) + if (unlikely(ptrace && p->exit_state == EXIT_ZOMBIE && task_detached(p))) list_add(&p->ptrace_list, &ptrace_dead); } @@ -849,26 +854,26 @@ static void exit_notify(struct task_struct *tsk, int group_dead) * we have changed execution domain as these two values started * the same after a fork. */ - if (tsk->exit_signal != SIGCHLD && tsk->exit_signal != -1 && + if (tsk->exit_signal != SIGCHLD && !task_detached(tsk) && (tsk->parent_exec_id != tsk->real_parent->self_exec_id || - tsk->self_exec_id != tsk->parent_exec_id) - && !capable(CAP_KILL)) + tsk->self_exec_id != tsk->parent_exec_id) && + !capable(CAP_KILL)) tsk->exit_signal = SIGCHLD; - /* If something other than our normal parent is ptracing us, then * send it a SIGCHLD instead of honoring exit_signal. exit_signal * only has special meaning to our real parent. */ - if (tsk->exit_signal != -1 && thread_group_empty(tsk)) { - int signal = tsk->parent == tsk->real_parent ? tsk->exit_signal : SIGCHLD; + if (!task_detached(tsk) && thread_group_empty(tsk)) { + int signal = (tsk->parent == tsk->real_parent) + ? tsk->exit_signal : SIGCHLD; do_notify_parent(tsk, signal); } else if (tsk->ptrace) { do_notify_parent(tsk, SIGCHLD); } state = EXIT_ZOMBIE; - if (tsk->exit_signal == -1 && likely(!tsk->ptrace)) + if (task_detached(tsk) && likely(!tsk->ptrace)) state = EXIT_DEAD; tsk->exit_state = state; @@ -1173,7 +1178,7 @@ static int eligible_child(enum pid_type type, struct pid *pid, int options, * Do not consider detached threads that are * not ptraced: */ - if (p->exit_signal == -1 && !p->ptrace) + if (task_detached(p) && !p->ptrace) return 0; /* Wait for all children (clone and not) if __WALL is set; @@ -1365,9 +1370,9 @@ static int wait_task_zombie(struct task_struct *p, int noreap, * If it's still not detached after that, don't release * it now. */ - if (p->exit_signal != -1) { + if (!task_detached(p)) { do_notify_parent(p, p->exit_signal); - if (p->exit_signal != -1) { + if (!task_detached(p)) { p->exit_state = EXIT_ZOMBIE; p = NULL; }