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Date: Mon, 13 Aug 2012 18:49:42 -0700
From: Tejun Heo <tj@...nel.org>
To: linux-kernel@...r.kernel.org
Cc: torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
mingo@...hat.com, lauro.venancio@...nbossa.org, jak@...-linux.org,
Tejun Heo <tj@...nel.org>
Subject: [PATCH 2/6] 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@...nel.org>
---
include/linux/workqueue.h | 14 +++++-
kernel/workqueue.c | 122 ++++-----------------------------------------
2 files changed, 22 insertions(+), 114 deletions(-)
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 6cd8f91..b2716b6 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -412,11 +412,9 @@ extern int keventd_up(void);
int execute_in_process_context(work_func_t fn, struct execute_work *);
extern bool flush_work(struct work_struct *work);
-extern bool flush_work_sync(struct work_struct *work);
extern bool cancel_work_sync(struct work_struct *work);
extern bool flush_delayed_work(struct delayed_work *dwork);
-extern bool flush_delayed_work_sync(struct delayed_work *work);
extern bool cancel_delayed_work(struct delayed_work *dwork);
extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
@@ -441,6 +439,18 @@ static inline bool __deprecated __cancel_delayed_work(struct delayed_work *work)
return ret;
}
+/* used to be different but now identical to flush_work(), deprecated */
+static inline bool flush_work_sync(struct work_struct *work)
+{
+ return flush_work(work);
+}
+
+/* used to be different but now identical to flush_delayed_work(), deprecated */
+static inline bool flush_delayed_work_sync(struct delayed_work *dwork)
+{
+ return flush_delayed_work(dwork);
+}
+
#ifndef CONFIG_SMP
static inline long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
{
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 26f048b..938adc0 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2780,8 +2780,7 @@ reflush:
}
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;
@@ -2803,13 +2802,12 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr,
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);
@@ -2836,15 +2834,8 @@ already_gone:
* 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,
@@ -2857,85 +2848,15 @@ bool flush_work(struct work_struct *work)
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
- 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
+ } 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);
+EXPORT_SYMBOL_GPL(flush_work);
static bool __cancel_work_timer(struct work_struct *work, bool is_dwork)
{
@@ -2949,14 +2870,14 @@ static bool __cancel_work_timer(struct work_struct *work, bool is_dwork)
* 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;
}
@@ -3009,29 +2930,6 @@ bool flush_delayed_work(struct delayed_work *dwork)
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 - cancel a delayed work
* @dwork: delayed_work to cancel
*
--
1.7.7.3
--
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