Commit e2e8a142 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Christian Brauner
Browse files

pidfd: exit: kill the no longer used thread_group_exited() 



It was used by pidfd_poll() but now it has no callers.

If it finally finds a modular user we can revert this change, but note
that the comment above this helper and the changelog in 38fd525a
("exit: Factor thread_group_exited out of pidfd_poll") are not accurate,
thread_group_exited() won't return true if all other threads have passed
exit_notify() and are zombies, it returns true only when all other threads
are completely gone. Not to mention that it can only work if the task
identified by @pid is a thread-group leader.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20240205174347.GA31461@redhat.com


Reviewed-by: default avatarTycho Andersen <tandersen@netflix.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 9ed52108

include/linux/sched/signal.h

+0 −2
Original line number Diff line number Diff line
@@ -735,8 +735,6 @@ static inline int thread_group_empty(struct task_struct *p) 
#define delay_group_leader(p) \

		(thread_group_leader(p) && !thread_group_empty(p))



extern bool thread_group_exited(struct pid *pid);



extern struct sighand_struct *__lock_task_sighand(struct task_struct *task,

							unsigned long *flags);

kernel/exit.c

+0 −24
Original line number Diff line number Diff line
@@ -1900,30 +1900,6 @@ COMPAT_SYSCALL_DEFINE5(waitid, 
}

#endif



/**

 * thread_group_exited - check that a thread group has exited

 * @pid: tgid of thread group to be checked.

 *

 * Test if the thread group represented by tgid has exited (all

 * threads are zombies, dead or completely gone).

 *

 * Return: true if the thread group has exited. false otherwise.

 */

bool thread_group_exited(struct pid *pid)

{

	struct task_struct *task;

	bool exited;



	rcu_read_lock();

	task = pid_task(pid, PIDTYPE_PID);

	exited = !task ||

		(READ_ONCE(task->exit_state) && thread_group_empty(task));

	rcu_read_unlock();



	return exited;

}

EXPORT_SYMBOL(thread_group_exited);



/*

 * This needs to be __function_aligned as GCC implicitly makes any

 * implementation of abort() cold and drops alignment specified by