posix-timers: always do get_task_struct(timer->it_process)

Change the code to get/put timer->it_process regardless of
SIGEV_THREAD_ID.  This streamlines the create/destroy paths and allows us
to simplify the usage of exit_itimers() in de_thread().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: mingo@elte.hu
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 4 insertions, 6 deletions

diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index 3dfd15aecc60..bd9c931b3659 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -540,11 +540,10 @@ sys_timer_create(const clockid_t which_clock,
                          */
                         spin_lock_irqsave(&process->sighand->siglock, flags);
                         if (!(process->flags & PF_EXITING)) {
+                                get_task_struct(process);
                                 new_timer->it_process = process;
                                 list_add(&new_timer->list,
                                          &process->signal->posix_timers);
-                                if (new_timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
-                                        get_task_struct(process);
                                 spin_unlock_irqrestore(&process->sighand->siglock, flags);
                         } else {
                                 spin_unlock_irqrestore(&process->sighand->siglock, flags);
@@ -561,6 +560,7 @@ sys_timer_create(const clockid_t which_clock,
                 new_timer->it_sigev_signo = SIGALRM;
                 new_timer->it_sigev_value.sival_int = new_timer->it_id;
                 process = current->group_leader;
+                get_task_struct(process);
                 spin_lock_irqsave(&process->sighand->siglock, flags);
                 new_timer->it_process = process;
                 list_add(&new_timer->list, &process->signal->posix_timers);
@@ -853,8 +853,7 @@ retry_delete:
          * This keeps any tasks waiting on the spin lock from thinking
          * they got something (see the lock code above).
          */
-        if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
-                put_task_struct(timer->it_process);
+        put_task_struct(timer->it_process);
         timer->it_process = NULL;
 
         unlock_timer(timer, flags);
@@ -881,8 +880,7 @@ retry_delete:
          * This keeps any tasks waiting on the spin lock from thinking
          * they got something (see the lock code above).
          */
-        if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
-                put_task_struct(timer->it_process);
+        put_task_struct(timer->it_process);
         timer->it_process = NULL;
 
         unlock_timer(timer, flags);