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Biederman" , Tycho Andersen , linux-kernel@vger.kernel.org Subject: [PATCH] pidfd: exit: kill the no longer used thread_group_exited() Message-ID: <20240205174347.GA31461@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.4 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1790081927663535727 X-GMAIL-MSGID: 1790081927663535727 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 38fd525a4c61 ("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: Oleg Nesterov Reviewed-by: Tycho Andersen --- include/linux/sched/signal.h | 2 -- kernel/exit.c | 24 ------------------------ 2 files changed, 26 deletions(-) diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h index 4b7664c56208..0a0e23c45406 100644 --- a/include/linux/sched/signal.h +++ b/include/linux/sched/signal.h @@ -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); diff --git a/kernel/exit.c b/kernel/exit.c index 493647fd7c07..41a12630cbbc 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1896,30 +1896,6 @@ 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