workqueue: gut flush[_delayed]_work_sync()
Now that all workqueues are non-reentrant, flush[_delayed]_work_sync()
are equivalent to flush[_delayed]_work(). Drop the separate
implementation and make them thin wrappers around
flush[_delayed]_work().
* start_flush_work() no longer takes @wait_executing as the only left
user - flush_work() - always sets it to %true.
* __cancel_work_timer() uses flush_work() instead of wait_on_work().
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index c4feef9..5f13a9a 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2801,8 +2801,7 @@
}
EXPORT_SYMBOL_GPL(drain_workqueue);
-static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr,
- bool wait_executing)
+static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr)
{
struct worker *worker = NULL;
struct global_cwq *gcwq;
@@ -2824,13 +2823,12 @@
cwq = get_work_cwq(work);
if (unlikely(!cwq || gcwq != cwq->pool->gcwq))
goto already_gone;
- } else if (wait_executing) {
+ } else {
worker = find_worker_executing_work(gcwq, work);
if (!worker)
goto already_gone;
cwq = worker->current_cwq;
- } else
- goto already_gone;
+ }
insert_wq_barrier(cwq, barr, work, worker);
spin_unlock_irq(&gcwq->lock);
@@ -2857,15 +2855,8 @@
* flush_work - wait for a work to finish executing the last queueing instance
* @work: the work to flush
*
- * Wait until @work has finished execution. This function considers
- * only the last queueing instance of @work. If @work has been
- * enqueued across different CPUs on a non-reentrant workqueue or on
- * multiple workqueues, @work might still be executing on return on
- * some of the CPUs from earlier queueing.
- *
- * If @work was queued only on a non-reentrant, ordered or unbound
- * workqueue, @work is guaranteed to be idle on return if it hasn't
- * been requeued since flush started.
+ * Wait until @work has finished execution. @work is guaranteed to be idle
+ * on return if it hasn't been requeued since flush started.
*
* RETURNS:
* %true if flush_work() waited for the work to finish execution,
@@ -2878,86 +2869,16 @@
lock_map_acquire(&work->lockdep_map);
lock_map_release(&work->lockdep_map);
- if (start_flush_work(work, &barr, true)) {
+ if (start_flush_work(work, &barr)) {
wait_for_completion(&barr.done);
destroy_work_on_stack(&barr.work);
return true;
- } else
+ } else {
return false;
+ }
}
EXPORT_SYMBOL_GPL(flush_work);
-static bool wait_on_cpu_work(struct global_cwq *gcwq, struct work_struct *work)
-{
- struct wq_barrier barr;
- struct worker *worker;
-
- spin_lock_irq(&gcwq->lock);
-
- worker = find_worker_executing_work(gcwq, work);
- if (unlikely(worker))
- insert_wq_barrier(worker->current_cwq, &barr, work, worker);
-
- spin_unlock_irq(&gcwq->lock);
-
- if (unlikely(worker)) {
- wait_for_completion(&barr.done);
- destroy_work_on_stack(&barr.work);
- return true;
- } else
- return false;
-}
-
-static bool wait_on_work(struct work_struct *work)
-{
- bool ret = false;
- int cpu;
-
- might_sleep();
-
- lock_map_acquire(&work->lockdep_map);
- lock_map_release(&work->lockdep_map);
-
- for_each_gcwq_cpu(cpu)
- ret |= wait_on_cpu_work(get_gcwq(cpu), work);
- return ret;
-}
-
-/**
- * flush_work_sync - wait until a work has finished execution
- * @work: the work to flush
- *
- * Wait until @work has finished execution. On return, it's
- * guaranteed that all queueing instances of @work which happened
- * before this function is called are finished. In other words, if
- * @work hasn't been requeued since this function was called, @work is
- * guaranteed to be idle on return.
- *
- * RETURNS:
- * %true if flush_work_sync() waited for the work to finish execution,
- * %false if it was already idle.
- */
-bool flush_work_sync(struct work_struct *work)
-{
- struct wq_barrier barr;
- bool pending, waited;
-
- /* we'll wait for executions separately, queue barr only if pending */
- pending = start_flush_work(work, &barr, false);
-
- /* wait for executions to finish */
- waited = wait_on_work(work);
-
- /* wait for the pending one */
- if (pending) {
- wait_for_completion(&barr.done);
- destroy_work_on_stack(&barr.work);
- }
-
- return pending || waited;
-}
-EXPORT_SYMBOL_GPL(flush_work_sync);
-
static bool __cancel_work_timer(struct work_struct *work, bool is_dwork)
{
unsigned long flags;
@@ -2970,14 +2891,14 @@
* would be waiting for before retrying.
*/
if (unlikely(ret == -ENOENT))
- wait_on_work(work);
+ flush_work(work);
} while (unlikely(ret < 0));
/* tell other tasks trying to grab @work to back off */
mark_work_canceling(work);
local_irq_restore(flags);
- wait_on_work(work);
+ flush_work(work);
clear_work_data(work);
return ret;
}
@@ -3030,29 +2951,6 @@
EXPORT_SYMBOL(flush_delayed_work);
/**
- * flush_delayed_work_sync - wait for a dwork to finish
- * @dwork: the delayed work to flush
- *
- * Delayed timer is cancelled and the pending work is queued for
- * execution immediately. Other than timer handling, its behavior
- * is identical to flush_work_sync().
- *
- * RETURNS:
- * %true if flush_work_sync() waited for the work to finish execution,
- * %false if it was already idle.
- */
-bool flush_delayed_work_sync(struct delayed_work *dwork)
-{
- local_irq_disable();
- if (del_timer_sync(&dwork->timer))
- __queue_work(dwork->cpu,
- get_work_cwq(&dwork->work)->wq, &dwork->work);
- local_irq_enable();
- return flush_work_sync(&dwork->work);
-}
-EXPORT_SYMBOL(flush_delayed_work_sync);
-
-/**
* cancel_delayed_work_sync - cancel a delayed work and wait for it to finish
* @dwork: the delayed work cancel
*
