[patch 4/8] posix-timers: Move POSIX timer group exit related code out of do_exit()

[Thomas Gleixner <tglx@kernel.org>]

Move the POSIX timer group exit handling into the posix timer code and
provide a proper stub when POSIX timers are disabled in Kconfig.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@kernel.org>
---
 include/linux/posix-timers.h |    2 ++
 include/linux/sched/task.h   |    1 -
 kernel/exit.c                |    7 +++----
 kernel/time/posix-timers.c   |   16 +++++++++-------
 4 files changed, 14 insertions(+), 12 deletions(-)

--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -233,6 +233,7 @@ int update_rlimit_cpu(struct task_struct
 
 #ifdef CONFIG_POSIX_TIMERS
 void posixtimer_exec(void);
+void posixtimer_exit(void);
 
 static inline void posixtimer_putref(struct k_itimer *tmr)
 {
@@ -262,6 +263,7 @@ static inline bool posixtimer_valid(cons
 }
 #else  /* CONFIG_POSIX_TIMERS */
 static inline void posixtimer_exec(void) { }
+static inline void posixtimer_exit(void) { }
 static inline void posixtimer_sigqueue_getref(struct sigqueue *q) { }
 static inline void posixtimer_sigqueue_putref(struct sigqueue *q) { }
 #endif /* !CONFIG_POSIX_TIMERS */
--- a/include/linux/sched/task.h
+++ b/include/linux/sched/task.h
@@ -94,7 +94,6 @@ static inline void exit_thread(struct ta
 extern __noreturn void do_group_exit(int);
 
 extern void exit_files(struct task_struct *);
-extern void exit_itimers(struct task_struct *);
 
 extern pid_t kernel_clone(struct kernel_clone_args *kargs);
 struct task_struct *copy_process(struct pid *pid, int trace, int node,
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -963,13 +963,12 @@ void __noreturn do_exit(long code)
 			panic("Attempted to kill init! exitcode=0x%08x\n",
 				tsk->signal->group_exit_code ?: (int)code);
 
-#ifdef CONFIG_POSIX_TIMERS
-		hrtimer_cancel(&tsk->signal->real_timer);
-		exit_itimers(tsk);
-#endif
+		posixtimer_exit();
+
 		if (tsk->mm)
 			setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm);
 	}
+
 	acct_collect(code, group_dead);
 	if (group_dead)
 		tty_audit_exit();
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -1077,13 +1077,9 @@ SYSCALL_DEFINE1(timer_delete, timer_t, t
 	return 0;
 }
 
-/*
- * Invoked from do_exit() when the last thread of a thread group exits.
- * At that point no other task can access the timers of the dying
- * task anymore.
- */
-void exit_itimers(struct task_struct *tsk)
+static void posixtimer_delete_timers(void)
 {
+	struct task_struct *tsk = current;
 	struct hlist_head timers;
 	struct hlist_node *next;
 	struct k_itimer *timer;
@@ -1120,12 +1116,18 @@ void exit_itimers(struct task_struct *ts
 	}
 }
 
+void posixtimer_exit(void)
+{
+	hrtimer_cancel(&current->signal->real_timer);
+	posixtimer_delete_timers();
+}
+
 void posixtimer_exec(void)
 {
 	scoped_guard(spinlock_irq, &current->sighand->siglock)
 		posix_cpu_timers_exit(current);
 
-	exit_itimers(current);
+	posixtimer_delete_timers();
 	flush_itimer_signals();
 }