From: Oleg Nesterov insert_work() inserts the new work_struct before or after cwq->worklist, depending on the "int tail" parameter. Change it to accept "list_head *" instead, this shrinks .text a bit and allows us to insert the barrier after specific work_struct. Signed-off-by: Oleg Nesterov Cc: Jarek Poplawski Cc: Max Krasnyansky Cc: Peter Zijlstra Signed-off-by: Andrew Morton --- kernel/workqueue.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff -puN kernel/workqueue.c~workqueues-insert_work-use-list_head-instead-of-int-tail kernel/workqueue.c --- a/kernel/workqueue.c~workqueues-insert_work-use-list_head-instead-of-int-tail +++ a/kernel/workqueue.c @@ -125,7 +125,7 @@ struct cpu_workqueue_struct *get_wq_data } static void insert_work(struct cpu_workqueue_struct *cwq, - struct work_struct *work, int tail) + struct work_struct *work, struct list_head *head) { set_wq_data(work, cwq); /* @@ -133,10 +133,7 @@ static void insert_work(struct cpu_workq * result of list_add() below, see try_to_grab_pending(). */ smp_wmb(); - if (tail) - list_add_tail(&work->entry, &cwq->worklist); - else - list_add(&work->entry, &cwq->worklist); + list_add_tail(&work->entry, head); wake_up(&cwq->more_work); } @@ -147,7 +144,7 @@ static void __queue_work(struct cpu_work unsigned long flags; spin_lock_irqsave(&cwq->lock, flags); - insert_work(cwq, work, 1); + insert_work(cwq, work, &cwq->worklist); spin_unlock_irqrestore(&cwq->lock, flags); } @@ -337,14 +334,14 @@ static void wq_barrier_func(struct work_ } static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, - struct wq_barrier *barr, int tail) + struct wq_barrier *barr, struct list_head *head) { INIT_WORK(&barr->work, wq_barrier_func); __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work)); init_completion(&barr->done); - insert_work(cwq, &barr->work, tail); + insert_work(cwq, &barr->work, head); } static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) @@ -364,7 +361,7 @@ static int flush_cpu_workqueue(struct cp active = 0; spin_lock_irq(&cwq->lock); if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) { - insert_wq_barrier(cwq, &barr, 1); + insert_wq_barrier(cwq, &barr, &cwq->worklist); active = 1; } spin_unlock_irq(&cwq->lock); @@ -449,7 +446,7 @@ static void wait_on_cpu_work(struct cpu_ spin_lock_irq(&cwq->lock); if (unlikely(cwq->current_work == work)) { - insert_wq_barrier(cwq, &barr, 0); + insert_wq_barrier(cwq, &barr, cwq->worklist.next); running = 1; } spin_unlock_irq(&cwq->lock); _