* Derived from the taskqueue/keventd code by:
*
* David Woodhouse <dwmw2@infradead.org>
- * Andrew Morton <andrewm@uow.edu.au>
+ * Andrew Morton
* Kai Petzke <wpp@marie.physik.tu-berlin.de>
* Theodore Ts'o <tytso@mit.edu>
*
const char *name;
int singlethread;
int freezeable; /* Freeze threads during suspend */
+ int rt;
#ifdef CONFIG_LOCKDEP
struct lockdep_map lockdep_map;
#endif
}
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);
/*
* 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);
}
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);
}
*/
int queue_work(struct workqueue_struct *wq, struct work_struct *work)
{
- int ret = 0;
+ int ret;
+
+ ret = queue_work_on(get_cpu(), wq, work);
+ put_cpu();
- 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();
- ret = 1;
- }
return ret;
}
EXPORT_SYMBOL_GPL(queue_work);
BUG_ON(get_wq_data(work) != cwq);
work_clear_pending(work);
- lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
- lock_acquire(&lockdep_map, 0, 0, 0, 2, _THIS_IP_);
+ lock_map_acquire(&cwq->wq->lockdep_map);
+ lock_map_acquire(&lockdep_map);
f(work);
- lock_release(&lockdep_map, 1, _THIS_IP_);
- lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_);
+ lock_map_release(&lockdep_map);
+ lock_map_release(&cwq->wq->lockdep_map);
if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
printk(KERN_ERR "BUG: workqueue leaked lock or atomic: "
}
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)
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);
int cpu;
might_sleep();
- lock_acquire(&wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
- lock_release(&wq->lockdep_map, 1, _THIS_IP_);
+ lock_map_acquire(&wq->lockdep_map);
+ lock_map_release(&wq->lockdep_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_map_acquire(&cwq->wq->lockdep_map);
+ lock_map_release(&cwq->wq->lockdep_map);
+
+ 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.
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);
might_sleep();
- lock_acquire(&work->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
- lock_release(&work->lockdep_map, 1, _THIS_IP_);
+ lock_map_acquire(&work->lockdep_map);
+ lock_map_release(&work->lockdep_map);
cwq = get_wq_data(work);
if (!cwq)
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;
static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
{
+ struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
struct workqueue_struct *wq = cwq->wq;
const char *fmt = is_single_threaded(wq) ? "%s" : "%s/%d";
struct task_struct *p;
*/
if (IS_ERR(p))
return PTR_ERR(p);
-
+ if (cwq->wq->rt)
+ sched_setscheduler_nocheck(p, SCHED_FIFO, ¶m);
cwq->thread = p;
return 0;
struct workqueue_struct *__create_workqueue_key(const char *name,
int singlethread,
int freezeable,
+ int rt,
struct lock_class_key *key,
const char *lock_name)
{
lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
wq->singlethread = singlethread;
wq->freezeable = freezeable;
+ wq->rt = rt;
INIT_LIST_HEAD(&wq->list);
if (singlethread) {
err = create_workqueue_thread(cwq, singlethread_cpu);
start_workqueue_thread(cwq, -1);
} else {
- get_online_cpus();
+ cpu_maps_update_begin();
+ /*
+ * We must place this wq on list even if the code below fails.
+ * cpu_down(cpu) can remove cpu from cpu_populated_map before
+ * destroy_workqueue() takes the lock, in that case we leak
+ * cwq[cpu]->thread.
+ */
spin_lock(&workqueue_lock);
list_add(&wq->list, &workqueues);
spin_unlock(&workqueue_lock);
-
+ /*
+ * We must initialize cwqs for each possible cpu even if we
+ * are going to call destroy_workqueue() finally. Otherwise
+ * cpu_up() can hit the uninitialized cwq once we drop the
+ * lock.
+ */
for_each_possible_cpu(cpu) {
cwq = init_cpu_workqueue(wq, cpu);
if (err || !cpu_online(cpu))
err = create_workqueue_thread(cwq, cpu);
start_workqueue_thread(cwq, cpu);
}
- put_online_cpus();
+ cpu_maps_update_done();
}
if (err) {
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;
- lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
- lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_);
+ lock_map_acquire(&cwq->wq->lockdep_map);
+ lock_map_release(&cwq->wq->lockdep_map);
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.
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_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);
unsigned int cpu = (unsigned long)hcpu;
struct cpu_workqueue_struct *cwq;
struct workqueue_struct *wq;
+ int ret = NOTIFY_OK;
action &= ~CPU_TASKS_FROZEN;
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);
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);
case CPU_UP_CANCELED:
start_workqueue_thread(cwq, -1);
- case CPU_DEAD:
+ case CPU_POST_DEAD:
cleanup_workqueue_thread(cwq);
break;
}
switch (action) {
case CPU_UP_CANCELED:
- case CPU_DEAD:
+ case CPU_POST_DEAD:
cpu_clear(cpu, cpu_populated_map);
}
- return NOTIFY_OK;
+ return ret;
+}
+
+#ifdef CONFIG_SMP
+struct work_for_cpu {
+ struct work_struct work;
+ long (*fn)(void *);
+ void *arg;
+ long ret;
+};
+
+static void do_work_for_cpu(struct work_struct *w)
+{
+ struct work_for_cpu *wfc = container_of(w, struct work_for_cpu, work);
+
+ wfc->ret = wfc->fn(wfc->arg);
+}
+
+/**
+ * work_on_cpu - run a function in user context on a particular cpu
+ * @cpu: the cpu to run on
+ * @fn: the function to run
+ * @arg: the function arg
+ *
+ * This will return -EINVAL in the cpu is not online, or the return value
+ * of @fn otherwise.
+ */
+long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
+{
+ struct work_for_cpu wfc;
+
+ INIT_WORK(&wfc.work, do_work_for_cpu);
+ wfc.fn = fn;
+ wfc.arg = arg;
+ get_online_cpus();
+ if (unlikely(!cpu_online(cpu)))
+ wfc.ret = -EINVAL;
+ else {
+ schedule_work_on(cpu, &wfc.work);
+ flush_work(&wfc.work);
+ }
+ put_online_cpus();
+
+ return wfc.ret;
}
+EXPORT_SYMBOL_GPL(work_on_cpu);
+#endif /* CONFIG_SMP */
void __init init_workqueues(void)
{
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff