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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 <tj@kernel.org>
This commit is contained in:
Tejun Heo 2013-02-13 19:29:10 -08:00
parent 1dd638149f
commit 8d03ecfe47
1 changed files with 8 additions and 25 deletions
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33
kernel/workqueue.c
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@ -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;
struct worker *worker;
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;
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,