From 8d03ecfe471802d6afe97da97722b6924533aa82 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 13 Feb 2013 19:29:10 -0800 Subject: workqueue: reimplement is_chained_work() using current_wq_worker() is_chained_work() was added before current_wq_worker() and implemented its own ham-fisted way of finding out whether %current is a workqueue worker - it iterates through all possible workers. Drop the custom implementation and reimplement using current_wq_worker(). Signed-off-by: Tejun Heo --- kernel/workqueue.c | 33 ++++++++------------------------- 1 file changed, 8 insertions(+), 25 deletions(-) (limited to 'kernel/workqueue.c') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 0d26ab3aee59..ea7f696f1060 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1159,35 +1159,18 @@ static void insert_work(struct cpu_workqueue_struct *cwq, /* * Test whether @work is being queued from another work executing on the - * same workqueue. This is rather expensive and should only be used from - * cold paths. + * same workqueue. */ static bool is_chained_work(struct workqueue_struct *wq) { - unsigned long flags; - unsigned int cpu; - - for_each_cwq_cpu(cpu, wq) { - struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); - struct worker_pool *pool = cwq->pool; - struct worker *worker; - struct hlist_node *pos; - int i; + struct worker *worker; - spin_lock_irqsave(&pool->lock, flags); - for_each_busy_worker(worker, i, pos, pool) { - if (worker->task != current) - continue; - spin_unlock_irqrestore(&pool->lock, flags); - /* - * I'm @worker, no locking necessary. See if @work - * is headed to the same workqueue. - */ - return worker->current_cwq->wq == wq; - } - spin_unlock_irqrestore(&pool->lock, flags); - } - return false; + worker = current_wq_worker(); + /* + * Return %true iff I'm a worker execuing a work item on @wq. If + * I'm @worker, it's safe to dereference it without locking. + */ + return worker && worker->current_cwq->wq == wq; } static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, -- cgit v1.2.3