#include <linux/cpu.h>
#include <linux/notifier.h>
#include <linux/kthread.h>
+#include <linux/hardirq.h>
+#include <linux/mempolicy.h>
+#include <linux/freezer.h>
+#include <linux/kallsyms.h>
+#include <linux/debug_locks.h>
/*
* The per-CPU workqueue (if single thread, we always use the first
* possible cpu).
*
* The sequence counters are for flush_scheduled_work(). It wants to wait
- * until until all currently-scheduled works are completed, but it doesn't
+ * until all currently-scheduled works are completed, but it doesn't
* want to be livelocked by new, incoming ones. So it waits until
* remove_sequence is >= the insert_sequence which pertained when
* flush_scheduled_work() was called.
wait_queue_head_t work_done;
struct workqueue_struct *wq;
- task_t *thread;
+ struct task_struct *thread;
int run_depth; /* Detect run_workqueue() recursion depth */
+
+ int freezeable; /* Freeze the thread during suspend */
} ____cacheline_aligned;
/*
/* All the per-cpu workqueues on the system, for hotplug cpu to add/remove
threads to each one as cpus come/go. */
-static DEFINE_SPINLOCK(workqueue_lock);
+static DEFINE_MUTEX(workqueue_mutex);
static LIST_HEAD(workqueues);
static int singlethread_cpu;
return list_empty(&wq->list);
}
+/*
+ * Set the workqueue on which a work item is to be run
+ * - Must *only* be called if the pending flag is set
+ */
+static inline void set_wq_data(struct work_struct *work, void *wq)
+{
+ unsigned long new;
+
+ BUG_ON(!work_pending(work));
+
+ new = (unsigned long) wq | (1UL << WORK_STRUCT_PENDING);
+ new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work);
+ atomic_long_set(&work->data, new);
+}
+
+static inline void *get_wq_data(struct work_struct *work)
+{
+ return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK);
+}
+
+static int __run_work(struct cpu_workqueue_struct *cwq, struct work_struct *work)
+{
+ int ret = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&cwq->lock, flags);
+ /*
+ * We need to re-validate the work info after we've gotten
+ * the cpu_workqueue lock. We can run the work now iff:
+ *
+ * - the wq_data still matches the cpu_workqueue_struct
+ * - AND the work is still marked pending
+ * - AND the work is still on a list (which will be this
+ * workqueue_struct list)
+ *
+ * All these conditions are important, because we
+ * need to protect against the work being run right
+ * now on another CPU (all but the last one might be
+ * true if it's currently running and has not been
+ * released yet, for example).
+ */
+ if (get_wq_data(work) == cwq
+ && work_pending(work)
+ && !list_empty(&work->entry)) {
+ work_func_t f = work->func;
+ list_del_init(&work->entry);
+ spin_unlock_irqrestore(&cwq->lock, flags);
+
+ if (!test_bit(WORK_STRUCT_NOAUTOREL, work_data_bits(work)))
+ work_release(work);
+ f(work);
+
+ spin_lock_irqsave(&cwq->lock, flags);
+ cwq->remove_sequence++;
+ wake_up(&cwq->work_done);
+ ret = 1;
+ }
+ spin_unlock_irqrestore(&cwq->lock, flags);
+ return ret;
+}
+
+/**
+ * run_scheduled_work - run scheduled work synchronously
+ * @work: work to run
+ *
+ * This checks if the work was pending, and runs it
+ * synchronously if so. It returns a boolean to indicate
+ * whether it had any scheduled work to run or not.
+ *
+ * NOTE! This _only_ works for normal work_structs. You
+ * CANNOT use this for delayed work, because the wq data
+ * for delayed work will not point properly to the per-
+ * CPU workqueue struct, but will change!
+ */
+int fastcall run_scheduled_work(struct work_struct *work)
+{
+ for (;;) {
+ struct cpu_workqueue_struct *cwq;
+
+ if (!work_pending(work))
+ return 0;
+ if (list_empty(&work->entry))
+ return 0;
+ /* NOTE! This depends intimately on __queue_work! */
+ cwq = get_wq_data(work);
+ if (!cwq)
+ return 0;
+ if (__run_work(cwq, work))
+ return 1;
+ }
+}
+EXPORT_SYMBOL(run_scheduled_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);
- work->wq_data = cwq;
+ set_wq_data(work, cwq);
list_add_tail(&work->entry, &cwq->worklist);
cwq->insert_sequence++;
wake_up(&cwq->more_work);
spin_unlock_irqrestore(&cwq->lock, flags);
}
-/*
- * Queue work on a workqueue. Return non-zero if it was successfully
- * added.
+/**
+ * queue_work - queue work on a workqueue
+ * @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 the CPU it was submitted, but there is no
* guarantee that it will be processed by that CPU.
{
int ret = 0, cpu = get_cpu();
- if (!test_and_set_bit(0, &work->pending)) {
+ if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
if (unlikely(is_single_threaded(wq)))
cpu = singlethread_cpu;
BUG_ON(!list_empty(&work->entry));
put_cpu();
return ret;
}
+EXPORT_SYMBOL_GPL(queue_work);
static void delayed_work_timer_fn(unsigned long __data)
{
- struct work_struct *work = (struct work_struct *)__data;
- struct workqueue_struct *wq = work->wq_data;
+ struct delayed_work *dwork = (struct delayed_work *)__data;
+ struct workqueue_struct *wq = get_wq_data(&dwork->work);
int cpu = smp_processor_id();
if (unlikely(is_single_threaded(wq)))
cpu = singlethread_cpu;
- __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
+ __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), &dwork->work);
}
+/**
+ * queue_delayed_work - queue work on a workqueue after delay
+ * @wq: workqueue to use
+ * @dwork: delayable work to queue
+ * @delay: number of jiffies to wait before queueing
+ *
+ * Returns 0 if @work was already on a queue, non-zero otherwise.
+ */
int fastcall queue_delayed_work(struct workqueue_struct *wq,
- struct work_struct *work, unsigned long delay)
+ struct delayed_work *dwork, unsigned long delay)
{
int ret = 0;
- struct timer_list *timer = &work->timer;
+ struct timer_list *timer = &dwork->timer;
+ struct work_struct *work = &dwork->work;
- if (!test_and_set_bit(0, &work->pending)) {
+ if (delay == 0)
+ return queue_work(wq, work);
+
+ if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
BUG_ON(timer_pending(timer));
BUG_ON(!list_empty(&work->entry));
/* This stores wq for the moment, for the timer_fn */
- work->wq_data = wq;
+ set_wq_data(work, wq);
timer->expires = jiffies + delay;
- timer->data = (unsigned long)work;
+ timer->data = (unsigned long)dwork;
timer->function = delayed_work_timer_fn;
add_timer(timer);
ret = 1;
}
return ret;
}
+EXPORT_SYMBOL_GPL(queue_delayed_work);
+
+/**
+ * queue_delayed_work_on - queue work on specific CPU after delay
+ * @cpu: CPU number to execute work on
+ * @wq: workqueue to use
+ * @dwork: work to queue
+ * @delay: number of jiffies to wait before queueing
+ *
+ * Returns 0 if @work was already on a queue, non-zero otherwise.
+ */
+int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
+ struct delayed_work *dwork, unsigned long delay)
+{
+ int ret = 0;
+ struct timer_list *timer = &dwork->timer;
+ struct work_struct *work = &dwork->work;
+
+ if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
+ BUG_ON(timer_pending(timer));
+ BUG_ON(!list_empty(&work->entry));
+
+ /* This stores wq for the moment, for the timer_fn */
+ set_wq_data(work, wq);
+ timer->expires = jiffies + delay;
+ timer->data = (unsigned long)dwork;
+ timer->function = delayed_work_timer_fn;
+ add_timer_on(timer, cpu);
+ ret = 1;
+ }
+ return ret;
+}
+EXPORT_SYMBOL_GPL(queue_delayed_work_on);
static void run_workqueue(struct cpu_workqueue_struct *cwq)
{
while (!list_empty(&cwq->worklist)) {
struct work_struct *work = list_entry(cwq->worklist.next,
struct work_struct, entry);
- void (*f) (void *) = work->func;
- void *data = work->data;
+ work_func_t f = work->func;
list_del_init(cwq->worklist.next);
spin_unlock_irqrestore(&cwq->lock, flags);
- BUG_ON(work->wq_data != cwq);
- clear_bit(0, &work->pending);
- f(data);
+ BUG_ON(get_wq_data(work) != cwq);
+ if (!test_bit(WORK_STRUCT_NOAUTOREL, work_data_bits(work)))
+ work_release(work);
+ f(work);
+
+ if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
+ printk(KERN_ERR "BUG: workqueue leaked lock or atomic: "
+ "%s/0x%08x/%d\n",
+ current->comm, preempt_count(),
+ current->pid);
+ printk(KERN_ERR " last function: ");
+ print_symbol("%s\n", (unsigned long)f);
+ debug_show_held_locks(current);
+ dump_stack();
+ }
spin_lock_irqsave(&cwq->lock, flags);
cwq->remove_sequence++;
struct k_sigaction sa;
sigset_t blocked;
- current->flags |= PF_NOFREEZE;
+ if (!cwq->freezeable)
+ current->flags |= PF_NOFREEZE;
set_user_nice(current, -5);
sigprocmask(SIG_BLOCK, &blocked, NULL);
flush_signals(current);
+ /*
+ * We inherited MPOL_INTERLEAVE from the booting kernel.
+ * Set MPOL_DEFAULT to insure node local allocations.
+ */
+ numa_default_policy();
+
/* SIG_IGN makes children autoreap: see do_notify_parent(). */
sa.sa.sa_handler = SIG_IGN;
sa.sa.sa_flags = 0;
set_current_state(TASK_INTERRUPTIBLE);
while (!kthread_should_stop()) {
+ if (cwq->freezeable)
+ try_to_freeze();
+
add_wait_queue(&cwq->more_work, &wait);
if (list_empty(&cwq->worklist))
schedule();
}
}
-/*
+/**
* flush_workqueue - ensure that any scheduled work has run to completion.
+ * @wq: workqueue to flush
*
* Forces execution of the workqueue and blocks until its completion.
* This is typically used in driver shutdown handlers.
} else {
int cpu;
- lock_cpu_hotplug();
+ mutex_lock(&workqueue_mutex);
for_each_online_cpu(cpu)
flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu));
- unlock_cpu_hotplug();
+ mutex_unlock(&workqueue_mutex);
}
}
+EXPORT_SYMBOL_GPL(flush_workqueue);
static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq,
- int cpu)
+ int cpu, int freezeable)
{
struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu);
struct task_struct *p;
cwq->thread = NULL;
cwq->insert_sequence = 0;
cwq->remove_sequence = 0;
+ cwq->freezeable = freezeable;
INIT_LIST_HEAD(&cwq->worklist);
init_waitqueue_head(&cwq->more_work);
init_waitqueue_head(&cwq->work_done);
}
struct workqueue_struct *__create_workqueue(const char *name,
- int singlethread)
+ int singlethread, int freezeable)
{
int cpu, destroy = 0;
struct workqueue_struct *wq;
}
wq->name = name;
- /* We don't need the distraction of CPUs appearing and vanishing. */
- lock_cpu_hotplug();
+ mutex_lock(&workqueue_mutex);
if (singlethread) {
INIT_LIST_HEAD(&wq->list);
- p = create_workqueue_thread(wq, singlethread_cpu);
+ p = create_workqueue_thread(wq, singlethread_cpu, freezeable);
if (!p)
destroy = 1;
else
wake_up_process(p);
} else {
- spin_lock(&workqueue_lock);
list_add(&wq->list, &workqueues);
- spin_unlock(&workqueue_lock);
for_each_online_cpu(cpu) {
- p = create_workqueue_thread(wq, cpu);
+ p = create_workqueue_thread(wq, cpu, freezeable);
if (p) {
kthread_bind(p, cpu);
wake_up_process(p);
destroy = 1;
}
}
- unlock_cpu_hotplug();
+ mutex_unlock(&workqueue_mutex);
/*
* Was there any error during startup? If yes then clean up:
}
return wq;
}
+EXPORT_SYMBOL_GPL(__create_workqueue);
static void cleanup_workqueue_thread(struct workqueue_struct *wq, int cpu)
{
kthread_stop(p);
}
+/**
+ * destroy_workqueue - safely terminate a workqueue
+ * @wq: target workqueue
+ *
+ * Safely destroy a workqueue. All work currently pending will be done first.
+ */
void destroy_workqueue(struct workqueue_struct *wq)
{
int cpu;
flush_workqueue(wq);
/* We don't need the distraction of CPUs appearing and vanishing. */
- lock_cpu_hotplug();
+ mutex_lock(&workqueue_mutex);
if (is_single_threaded(wq))
cleanup_workqueue_thread(wq, singlethread_cpu);
else {
for_each_online_cpu(cpu)
cleanup_workqueue_thread(wq, cpu);
- spin_lock(&workqueue_lock);
list_del(&wq->list);
- spin_unlock(&workqueue_lock);
}
- unlock_cpu_hotplug();
+ mutex_unlock(&workqueue_mutex);
free_percpu(wq->cpu_wq);
kfree(wq);
}
+EXPORT_SYMBOL_GPL(destroy_workqueue);
static struct workqueue_struct *keventd_wq;
+/**
+ * schedule_work - put work task in global workqueue
+ * @work: job to be done
+ *
+ * This puts a job in the kernel-global workqueue.
+ */
int fastcall schedule_work(struct work_struct *work)
{
return queue_work(keventd_wq, work);
}
+EXPORT_SYMBOL(schedule_work);
-int fastcall schedule_delayed_work(struct work_struct *work, unsigned long delay)
+/**
+ * schedule_delayed_work - put work task in global workqueue after delay
+ * @dwork: job to be done
+ * @delay: number of jiffies to wait or 0 for immediate execution
+ *
+ * After waiting for a given time this puts a job in the kernel-global
+ * workqueue.
+ */
+int fastcall schedule_delayed_work(struct delayed_work *dwork, unsigned long delay)
{
- return queue_delayed_work(keventd_wq, work, delay);
+ return queue_delayed_work(keventd_wq, dwork, delay);
}
+EXPORT_SYMBOL(schedule_delayed_work);
+/**
+ * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
+ * @cpu: cpu to use
+ * @dwork: job to be done
+ * @delay: number of jiffies to wait
+ *
+ * After waiting for a given time this puts a job in the kernel-global
+ * workqueue on the specified CPU.
+ */
int schedule_delayed_work_on(int cpu,
- struct work_struct *work, unsigned long delay)
+ struct delayed_work *dwork, unsigned long delay)
{
- int ret = 0;
- struct timer_list *timer = &work->timer;
-
- if (!test_and_set_bit(0, &work->pending)) {
- BUG_ON(timer_pending(timer));
- BUG_ON(!list_empty(&work->entry));
- /* This stores keventd_wq for the moment, for the timer_fn */
- work->wq_data = keventd_wq;
- timer->expires = jiffies + delay;
- timer->data = (unsigned long)work;
- timer->function = delayed_work_timer_fn;
- add_timer_on(timer, cpu);
- ret = 1;
- }
- return ret;
+ return queue_delayed_work_on(cpu, keventd_wq, dwork, delay);
}
+EXPORT_SYMBOL(schedule_delayed_work_on);
-int schedule_on_each_cpu(void (*func) (void *info), void *info)
+/**
+ * schedule_on_each_cpu - call a function on each online CPU from keventd
+ * @func: the function to call
+ *
+ * Returns zero on success.
+ * Returns -ve errno on failure.
+ *
+ * Appears to be racy against CPU hotplug.
+ *
+ * schedule_on_each_cpu() is very slow.
+ */
+int schedule_on_each_cpu(work_func_t func)
{
int cpu;
- struct work_struct *work;
+ struct work_struct *works;
- work = kmalloc(NR_CPUS * sizeof(struct work_struct), GFP_KERNEL);
-
- if (!work)
+ works = alloc_percpu(struct work_struct);
+ if (!works)
return -ENOMEM;
+
+ mutex_lock(&workqueue_mutex);
for_each_online_cpu(cpu) {
- INIT_WORK(work + cpu, func, info);
- __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu),
- work + cpu);
+ 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);
}
+ mutex_unlock(&workqueue_mutex);
flush_workqueue(keventd_wq);
- kfree(work);
+ free_percpu(works);
return 0;
}
{
flush_workqueue(keventd_wq);
}
+EXPORT_SYMBOL(flush_scheduled_work);
/**
* cancel_rearming_delayed_workqueue - reliably kill off a delayed
* work whose handler rearms the delayed work.
* @wq: the controlling workqueue structure
- * @work: the delayed work struct
+ * @dwork: the delayed work struct
*/
void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq,
- struct work_struct *work)
+ struct delayed_work *dwork)
{
- while (!cancel_delayed_work(work))
+ while (!cancel_delayed_work(dwork))
flush_workqueue(wq);
}
EXPORT_SYMBOL(cancel_rearming_delayed_workqueue);
/**
* cancel_rearming_delayed_work - reliably kill off a delayed keventd
* work whose handler rearms the delayed work.
- * @work: the delayed work struct
+ * @dwork: the delayed work struct
*/
-void cancel_rearming_delayed_work(struct work_struct *work)
+void cancel_rearming_delayed_work(struct delayed_work *dwork)
{
- cancel_rearming_delayed_workqueue(keventd_wq, work);
+ cancel_rearming_delayed_workqueue(keventd_wq, dwork);
}
EXPORT_SYMBOL(cancel_rearming_delayed_work);
+/**
+ * execute_in_process_context - reliably execute the routine with user context
+ * @fn: the function to execute
+ * @ew: guaranteed storage for the execute work structure (must
+ * be available when the work executes)
+ *
+ * Executes the function immediately if process context is available,
+ * otherwise schedules the function for delayed execution.
+ *
+ * Returns: 0 - function was executed
+ * 1 - function was scheduled for execution
+ */
+int execute_in_process_context(work_func_t fn, struct execute_work *ew)
+{
+ if (!in_interrupt()) {
+ fn(&ew->work);
+ return 0;
+ }
+
+ INIT_WORK(&ew->work, fn);
+ schedule_work(&ew->work);
+
+ return 1;
+}
+EXPORT_SYMBOL_GPL(execute_in_process_context);
+
int keventd_up(void)
{
return keventd_wq != NULL;
}
-#ifdef CONFIG_HOTPLUG_CPU
/* Take the work from this (downed) CPU. */
static void take_over_work(struct workqueue_struct *wq, unsigned int cpu)
{
struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu);
- LIST_HEAD(list);
+ struct list_head list;
struct work_struct *work;
spin_lock_irq(&cwq->lock);
- list_splice_init(&cwq->worklist, &list);
+ list_replace_init(&cwq->worklist, &list);
while (!list_empty(&list)) {
printk("Taking work for %s\n", wq->name);
switch (action) {
case CPU_UP_PREPARE:
+ mutex_lock(&workqueue_mutex);
/* Create a new workqueue thread for it. */
list_for_each_entry(wq, &workqueues, list) {
- if (!create_workqueue_thread(wq, hotcpu)) {
+ if (!create_workqueue_thread(wq, hotcpu, 0)) {
printk("workqueue for %i failed\n", hotcpu);
return NOTIFY_BAD;
}
kthread_bind(cwq->thread, hotcpu);
wake_up_process(cwq->thread);
}
+ mutex_unlock(&workqueue_mutex);
break;
case CPU_UP_CANCELED:
list_for_each_entry(wq, &workqueues, list) {
+ if (!per_cpu_ptr(wq->cpu_wq, hotcpu)->thread)
+ continue;
/* Unbind so it can run. */
kthread_bind(per_cpu_ptr(wq->cpu_wq, hotcpu)->thread,
any_online_cpu(cpu_online_map));
cleanup_workqueue_thread(wq, hotcpu);
}
+ mutex_unlock(&workqueue_mutex);
+ break;
+
+ case CPU_DOWN_PREPARE:
+ mutex_lock(&workqueue_mutex);
+ break;
+
+ case CPU_DOWN_FAILED:
+ mutex_unlock(&workqueue_mutex);
break;
case CPU_DEAD:
cleanup_workqueue_thread(wq, hotcpu);
list_for_each_entry(wq, &workqueues, list)
take_over_work(wq, hotcpu);
+ mutex_unlock(&workqueue_mutex);
break;
}
return NOTIFY_OK;
}
-#endif
void init_workqueues(void)
{
BUG_ON(!keventd_wq);
}
-EXPORT_SYMBOL_GPL(__create_workqueue);
-EXPORT_SYMBOL_GPL(queue_work);
-EXPORT_SYMBOL_GPL(queue_delayed_work);
-EXPORT_SYMBOL_GPL(flush_workqueue);
-EXPORT_SYMBOL_GPL(destroy_workqueue);
-
-EXPORT_SYMBOL(schedule_work);
-EXPORT_SYMBOL(schedule_delayed_work);
-EXPORT_SYMBOL(schedule_delayed_work_on);
-EXPORT_SYMBOL(flush_scheduled_work);
git://git.onelab.eu / linux-2.6.git / blobdiff