posix-timers: Remove "it_signal = NULL" assignment in itimer_delete()

itimer_delete() is invoked during do_exit(). At this point it is the
last thread in the group dying and doing the clean up.
Since it is the last thread in the group, there can not be any other
task attempting to lock the itimer which means the NULL assignment (which
avoids lookups in __lock_timer()) is not required.

The assignment and comment was copied in commit 0e568881178ff ("[PATCH]
fix posix-timers to have proper per-process scope") from
sys_timer_delete() which was/is the syscall interface and requires the
assignment.

Remove the superfluous ->it_signal = NULL assignment.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190621143643.25649-2-bigeasy@linutronix.de

diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 29176635991f032c2fa3059c835b1dd9646f1ad6..caa63e58e3d885f98739f24383e95bb74b5ef381 100644 (file)
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -990,11 +990,6 @@ retry_delete:
                goto retry_delete;
        }
        list_del(&timer->list);
-       /*
-        * This keeps any tasks waiting on the spin lock from thinking
-        * they got something (see the lock code above).
-        */
-       timer->it_signal = NULL;
 
        unlock_timer(timer, flags);
        release_posix_timer(timer, IT_ID_SET);