summaryrefslogtreecommitdiffstats
path: root/kernel/workqueue.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/workqueue.c')
-rw-r--r--kernel/workqueue.c149
1 files changed, 117 insertions, 32 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index ce7799540c9..ec7e4f62aaf 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -125,7 +125,7 @@ struct cpu_workqueue_struct *get_wq_data(struct work_struct *work)
}
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);
/*
@@ -133,21 +133,17 @@ static void insert_work(struct cpu_workqueue_struct *cwq,
* 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);
}
-/* Preempt must be disabled. */
static void __queue_work(struct cpu_workqueue_struct *cwq,
struct work_struct *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);
}
@@ -163,17 +159,39 @@ static void __queue_work(struct cpu_workqueue_struct *cwq,
*/
int queue_work(struct workqueue_struct *wq, struct work_struct *work)
{
+ int ret;
+
+ ret = queue_work_on(get_cpu(), wq, work);
+ put_cpu();
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(queue_work);
+
+/**
+ * queue_work_on - queue work on specific cpu
+ * @cpu: CPU number to execute work on
+ * @wq: workqueue to use
+ * @work: work to queue
+ *
+ * Returns 0 if @work was already on a queue, non-zero otherwise.
+ *
+ * We queue the work to a specific CPU, the caller must ensure it
+ * can't go away.
+ */
+int
+queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work)
+{
int ret = 0;
if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
BUG_ON(!list_empty(&work->entry));
- __queue_work(wq_per_cpu(wq, get_cpu()), work);
- put_cpu();
+ __queue_work(wq_per_cpu(wq, cpu), work);
ret = 1;
}
return ret;
}
-EXPORT_SYMBOL_GPL(queue_work);
+EXPORT_SYMBOL_GPL(queue_work_on);
static void delayed_work_timer_fn(unsigned long __data)
{
@@ -337,14 +355,14 @@ static void wq_barrier_func(struct work_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 +382,7 @@ static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq)
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);
@@ -397,11 +415,62 @@ void flush_workqueue(struct workqueue_struct *wq)
might_sleep();
lock_acquire(&wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
lock_release(&wq->lockdep_map, 1, _THIS_IP_);
- for_each_cpu_mask(cpu, *cpu_map)
+ for_each_cpu_mask_nr(cpu, *cpu_map)
flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu));
}
EXPORT_SYMBOL_GPL(flush_workqueue);
+/**
+ * flush_work - block until a work_struct's callback has terminated
+ * @work: the work which is to be flushed
+ *
+ * Returns false if @work has already terminated.
+ *
+ * It is expected that, prior to calling flush_work(), the caller has
+ * arranged for the work to not be requeued, otherwise it doesn't make
+ * sense to use this function.
+ */
+int flush_work(struct work_struct *work)
+{
+ struct cpu_workqueue_struct *cwq;
+ struct list_head *prev;
+ struct wq_barrier barr;
+
+ might_sleep();
+ cwq = get_wq_data(work);
+ if (!cwq)
+ return 0;
+
+ lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
+ lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_);
+
+ prev = NULL;
+ spin_lock_irq(&cwq->lock);
+ if (!list_empty(&work->entry)) {
+ /*
+ * See the comment near try_to_grab_pending()->smp_rmb().
+ * If it was re-queued under us we are not going to wait.
+ */
+ smp_rmb();
+ if (unlikely(cwq != get_wq_data(work)))
+ goto out;
+ prev = &work->entry;
+ } else {
+ if (cwq->current_work != work)
+ goto out;
+ prev = &cwq->worklist;
+ }
+ insert_wq_barrier(cwq, &barr, prev->next);
+out:
+ spin_unlock_irq(&cwq->lock);
+ if (!prev)
+ return 0;
+
+ wait_for_completion(&barr.done);
+ return 1;
+}
+EXPORT_SYMBOL_GPL(flush_work);
+
/*
* Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit,
* so this work can't be re-armed in any way.
@@ -449,7 +518,7 @@ static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq,
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);
@@ -477,7 +546,7 @@ static void wait_on_work(struct work_struct *work)
wq = cwq->wq;
cpu_map = wq_cpu_map(wq);
- for_each_cpu_mask(cpu, *cpu_map)
+ for_each_cpu_mask_nr(cpu, *cpu_map)
wait_on_cpu_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
}
@@ -553,6 +622,19 @@ int schedule_work(struct work_struct *work)
}
EXPORT_SYMBOL(schedule_work);
+/*
+ * schedule_work_on - put work task on a specific cpu
+ * @cpu: cpu to put the work task on
+ * @work: job to be done
+ *
+ * This puts a job on a specific cpu
+ */
+int schedule_work_on(int cpu, struct work_struct *work)
+{
+ return queue_work_on(cpu, keventd_wq, work);
+}
+EXPORT_SYMBOL(schedule_work_on);
+
/**
* schedule_delayed_work - put work task in global workqueue after delay
* @dwork: job to be done
@@ -607,10 +689,10 @@ int schedule_on_each_cpu(work_func_t func)
struct work_struct *work = per_cpu_ptr(works, cpu);
INIT_WORK(work, func);
- set_bit(WORK_STRUCT_PENDING, work_data_bits(work));
- __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), work);
+ schedule_work_on(cpu, work);
}
- flush_workqueue(keventd_wq);
+ for_each_online_cpu(cpu)
+ flush_work(per_cpu_ptr(works, cpu));
put_online_cpus();
free_percpu(works);
return 0;
@@ -747,7 +829,7 @@ struct workqueue_struct *__create_workqueue_key(const char *name,
err = create_workqueue_thread(cwq, singlethread_cpu);
start_workqueue_thread(cwq, -1);
} else {
- get_online_cpus();
+ cpu_maps_update_begin();
spin_lock(&workqueue_lock);
list_add(&wq->list, &workqueues);
spin_unlock(&workqueue_lock);
@@ -759,7 +841,7 @@ struct workqueue_struct *__create_workqueue_key(const char *name,
err = create_workqueue_thread(cwq, cpu);
start_workqueue_thread(cwq, cpu);
}
- put_online_cpus();
+ cpu_maps_update_done();
}
if (err) {
@@ -773,8 +855,8 @@ EXPORT_SYMBOL_GPL(__create_workqueue_key);
static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq)
{
/*
- * Our caller is either destroy_workqueue() or CPU_DEAD,
- * get_online_cpus() protects cwq->thread.
+ * Our caller is either destroy_workqueue() or CPU_POST_DEAD,
+ * cpu_add_remove_lock protects cwq->thread.
*/
if (cwq->thread == NULL)
return;
@@ -784,7 +866,7 @@ static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq)
flush_cpu_workqueue(cwq);
/*
- * If the caller is CPU_DEAD and cwq->worklist was not empty,
+ * If the caller is CPU_POST_DEAD and cwq->worklist was not empty,
* a concurrent flush_workqueue() can insert a barrier after us.
* However, in that case run_workqueue() won't return and check
* kthread_should_stop() until it flushes all work_struct's.
@@ -808,14 +890,14 @@ void destroy_workqueue(struct workqueue_struct *wq)
const cpumask_t *cpu_map = wq_cpu_map(wq);
int cpu;
- get_online_cpus();
+ cpu_maps_update_begin();
spin_lock(&workqueue_lock);
list_del(&wq->list);
spin_unlock(&workqueue_lock);
- for_each_cpu_mask(cpu, *cpu_map)
+ for_each_cpu_mask_nr(cpu, *cpu_map)
cleanup_workqueue_thread(per_cpu_ptr(wq->cpu_wq, cpu));
- put_online_cpus();
+ cpu_maps_update_done();
free_percpu(wq->cpu_wq);
kfree(wq);
@@ -829,6 +911,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
unsigned int cpu = (unsigned long)hcpu;
struct cpu_workqueue_struct *cwq;
struct workqueue_struct *wq;
+ int ret = NOTIFY_OK;
action &= ~CPU_TASKS_FROZEN;
@@ -836,7 +919,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
case CPU_UP_PREPARE:
cpu_set(cpu, cpu_populated_map);
}
-
+undo:
list_for_each_entry(wq, &workqueues, list) {
cwq = per_cpu_ptr(wq->cpu_wq, cpu);
@@ -846,7 +929,9 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
break;
printk(KERN_ERR "workqueue [%s] for %i failed\n",
wq->name, cpu);
- return NOTIFY_BAD;
+ action = CPU_UP_CANCELED;
+ ret = NOTIFY_BAD;
+ goto undo;
case CPU_ONLINE:
start_workqueue_thread(cwq, cpu);
@@ -854,7 +939,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
case CPU_UP_CANCELED:
start_workqueue_thread(cwq, -1);
- case CPU_DEAD:
+ case CPU_POST_DEAD:
cleanup_workqueue_thread(cwq);
break;
}
@@ -862,11 +947,11 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
switch (action) {
case CPU_UP_CANCELED:
- case CPU_DEAD:
+ case CPU_POST_DEAD:
cpu_clear(cpu, cpu_populated_map);
}
- return NOTIFY_OK;
+ return ret;
}
void __init init_workqueues(void)