exit: reparent: introduce find_alive_thread()
Add the new simple helper to factor out the for_each_thread() code in
find_child_reaper() and find_new_reaper(). It can also simplify the
potential PF_EXITING -> exit_state change, plus perhaps we can change this
code to take SIGNAL_GROUP_EXIT into account.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Sterling Alexander <stalexan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/exit.c b/kernel/exit.c
index 930fbe1..b0f482f 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -459,6 +459,17 @@
clear_thread_flag(TIF_MEMDIE);
}
+static struct task_struct *find_alive_thread(struct task_struct *p)
+{
+ struct task_struct *t;
+
+ for_each_thread(p, t) {
+ if (!(t->flags & PF_EXITING))
+ return t;
+ }
+ return NULL;
+}
+
static struct task_struct *find_child_reaper(struct task_struct *father)
__releases(&tasklist_lock)
__acquires(&tasklist_lock)
@@ -469,9 +480,8 @@
if (likely(reaper != father))
return reaper;
- for_each_thread(father, reaper) {
- if (reaper->flags & PF_EXITING)
- continue;
+ reaper = find_alive_thread(father);
+ if (reaper) {
pid_ns->child_reaper = reaper;
return reaper;
}
@@ -497,16 +507,13 @@
static struct task_struct *find_new_reaper(struct task_struct *father,
struct task_struct *child_reaper)
{
- struct task_struct *thread;
+ struct task_struct *thread, *reaper;
- for_each_thread(father, thread) {
- if (thread->flags & PF_EXITING)
- continue;
+ thread = find_alive_thread(father);
+ if (thread)
return thread;
- }
if (father->signal->has_child_subreaper) {
- struct task_struct *reaper;
/*
* Find the first ->is_child_subreaper ancestor in our pid_ns.
* We start from father to ensure we can not look into another
@@ -520,10 +527,9 @@
break;
if (!reaper->signal->is_child_subreaper)
continue;
- for_each_thread(reaper, thread) {
- if (!(thread->flags & PF_EXITING))
- return thread;
- }
+ thread = find_alive_thread(reaper);
+ if (thread)
+ return thread;
}
}