[PATCH] posix-timers: omit posix_cpu_timers_init_group when CONFIG_POSIX_TIMERS is disabled

[Liya Huang <1425075683@qq.com>]

    When POSIX timers are disabled (CONFIG_POSIX_TIMERS=n), the helper
    function posix_cpu_timers_init_group() is effectively a no-op—but it
    still consumes valuable code space. To avoid generating an empty stub,
    we should conditionally compile this function out entirely when POSIX
    timers support is turned off.

This logic was originally introduced in commit b18b6a9cef7f ("timers:
    Omit POSIX timer stuff from task_struct when disabled"), but was
    dropped in commit 244d49e30653 ("posix-cpu-timers: Move state tracking
     to struct posix_cputimers")

---
Signed-off-by: Liya Huang <1425075683@qq.com>
---
 kernel/fork.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/fork.c b/kernel/fork.c
index 168681fc4b25a9fddcb90ce155c027551455f4ee..9632e863c17b44424fadc40b2445034ec5cd20d6 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1883,6 +1883,7 @@ void __cleanup_sighand(struct sighand_struct *sighand)
 	}
 }
 
+#ifdef CONFIG_POSIX_TIMERS
 /*
  * Initialize POSIX timer handling for a thread group.
  */
@@ -1894,6 +1895,9 @@ static void posix_cpu_timers_init_group(struct signal_struct *sig)
 	cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
 	posix_cputimers_group_init(pct, cpu_limit);
 }
+#else
+static inline void posix_cpu_timers_init_group(struct signal_struct *sig) { }
+#endif
 
 static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
 {

---
base-commit: 0ff41df1cb268fc69e703a08a57ee14ae967d0ca
change-id: 20250607-posix_cpu_timers_init_group-0439fe81f23a

Best regards,
-- 
Liya Huang <1425075683@qq.com>