move exit_task_work() past exit_files() et.al.

... and get rid of PF_EXITING check in task_work_add().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/kernel/exit.c b/kernel/exit.c
index 2f59cc334516a9b9e831bb54aa0375c999ae69b2..d17f6c4ddfa9755f4318413805f9b64417b34d47 100644 (file)
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -953,14 +953,11 @@ void do_exit(long code)
        exit_signals(tsk);  /* sets PF_EXITING */
        /*
         * tsk->flags are checked in the futex code to protect against
-        * an exiting task cleaning up the robust pi futexes, and in
-        * task_work_add() to avoid the race with exit_task_work().
+        * an exiting task cleaning up the robust pi futexes.
         */
        smp_mb();
        raw_spin_unlock_wait(&tsk->pi_lock);
 
-       exit_task_work(tsk);
-
        if (unlikely(in_atomic()))
                printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
                                current->comm, task_pid_nr(current),
@@ -995,6 +992,7 @@ void do_exit(long code)
        exit_shm(tsk);
        exit_files(tsk);
        exit_fs(tsk);
+       exit_task_work(tsk);
        check_stack_usage();
        exit_thread();
 

diff --git a/kernel/task_work.c b/kernel/task_work.c
index 76266fb665dcf8b21f0416c67df3fd8efd165ae6..fb396089f66a4def58e8c4e57f612cecf3b5b0a6 100644 (file)
--- a/kernel/task_work.c
+++ b/kernel/task_work.c
@@ -5,34 +5,26 @@
 int
 task_work_add(struct task_struct *task, struct callback_head *twork, bool notify)
 {
+       struct callback_head *last, *first;
        unsigned long flags;
-       int err = -ESRCH;
 
-#ifndef TIF_NOTIFY_RESUME
-       if (notify)
-               return -ENOTSUPP;
-#endif
        /*
-        * We must not insert the new work if the task has already passed
-        * exit_task_work(). We rely on do_exit()->raw_spin_unlock_wait()
-        * and check PF_EXITING under pi_lock.
+        * Not inserting the new work if the task has already passed
+        * exit_task_work() is the responisbility of callers.
         */
        raw_spin_lock_irqsave(&task->pi_lock, flags);
-       if (likely(!(task->flags & PF_EXITING))) {
-               struct callback_head *last = task->task_works;
-               struct callback_head *first = last ? last->next : twork;
-               twork->next = first;
-               if (last)
-                       last->next = twork;
-               task->task_works = twork;
-               err = 0;
-       }
+       last = task->task_works;
+       first = last ? last->next : twork;
+       twork->next = first;
+       if (last)
+               last->next = twork;
+       task->task_works = twork;
        raw_spin_unlock_irqrestore(&task->pi_lock, flags);
 
        /* test_and_set_bit() implies mb(), see tracehook_notify_resume(). */
-       if (likely(!err) && notify)
+       if (notify)
                set_notify_resume(task);
-       return err;
+       return 0;
 }
 
 struct callback_head *