task_work: minor cleanups

Trivial.  Remove the unnecessary "work = NULL" initialization and turn
read_barrier_depends() into smp_read_barrier_depends() in
task_work_cancel().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/task_work.c b/kernel/task_work.c
index 65bd3c92d6f3a14cf9db95f9ab7e22c368457661..6ee09856f72505739f2bc520a1fb0b1a0200328e 100644 (file)
--- a/kernel/task_work.c
+++ b/kernel/task_work.c
@@ -25,7 +25,7 @@ struct callback_head *
 task_work_cancel(struct task_struct *task, task_work_func_t func)
 {
        struct callback_head **pprev = &task->task_works;
-       struct callback_head *work = NULL;
+       struct callback_head *work;
        unsigned long flags;
        /*
         * If cmpxchg() fails we continue without updating pprev.
@@ -35,7 +35,7 @@ task_work_cancel(struct task_struct *task, task_work_func_t func)
         */
        raw_spin_lock_irqsave(&task->pi_lock, flags);
        while ((work = ACCESS_ONCE(*pprev))) {
-               read_barrier_depends();
+               smp_read_barrier_depends();
                if (work->func != func)
                        pprev = &work->next;
                else if (cmpxchg(pprev, work, work->next) == work)