Merge branch 'dde' into upstream-merged

1 files changed, 1038 insertions, 0 deletions

diff --git a/libdde_linux26/lib/src/kernel/workqueue.c b/libdde_linux26/lib/src/kernel/workqueue.c
new file mode 100644
index 00000000..5ad26d9f
--- /dev/null
+++ b/libdde_linux26/lib/src/kernel/workqueue.c
@@ -0,0 +1,1038 @@
+/*
+ * linux/kernel/workqueue.c
+ *
+ * Generic mechanism for defining kernel helper threads for running
+ * arbitrary tasks in process context.
+ *
+ * Started by Ingo Molnar, Copyright (C) 2002
+ *
+ * Derived from the taskqueue/keventd code by:
+ *
+ *   David Woodhouse <dwmw2@infradead.org>
+ *   Andrew Morton
+ *   Kai Petzke <wpp@marie.physik.tu-berlin.de>
+ *   Theodore Ts'o <tytso@mit.edu>
+ *
+ * Made to use alloc_percpu by Christoph Lameter.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/signal.h>
+#include <linux/completion.h>
+#include <linux/workqueue.h>
+#include <linux/slab.h>
+#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>
+#include <linux/lockdep.h>
+
+#ifdef DDE_LINUX
+#include "local.h"
+#endif
+
+/*
+ * The per-CPU workqueue (if single thread, we always use the first
+ * possible cpu).
+ */
+struct cpu_workqueue_struct {
+
+	spinlock_t lock;
+
+	struct list_head worklist;
+	wait_queue_head_t more_work;
+	struct work_struct *current_work;
+
+	struct workqueue_struct *wq;
+	struct task_struct *thread;
+
+	int run_depth;		/* Detect run_workqueue() recursion depth */
+} ____cacheline_aligned;
+
+/*
+ * The externally visible workqueue abstraction is an array of
+ * per-CPU workqueues:
+ */
+struct workqueue_struct {
+	struct cpu_workqueue_struct *cpu_wq;
+	struct list_head list;
+	const char *name;
+	int singlethread;
+	int freezeable;		/* Freeze threads during suspend */
+	int rt;
+#ifdef CONFIG_LOCKDEP
+	struct lockdep_map lockdep_map;
+#endif
+};
+
+/* Serializes the accesses to the list of workqueues. */
+static DEFINE_SPINLOCK(workqueue_lock);
+static LIST_HEAD(workqueues);
+
+static int singlethread_cpu __read_mostly;
+static const struct cpumask *cpu_singlethread_map __read_mostly;
+/*
+ * _cpu_down() first removes CPU from cpu_online_map, then CPU_DEAD
+ * flushes cwq->worklist. This means that flush_workqueue/wait_on_work
+ * which comes in between can't use for_each_online_cpu(). We could
+ * use cpu_possible_map, the cpumask below is more a documentation
+ * than optimization.
+ */
+static cpumask_var_t cpu_populated_map __read_mostly;
+
+/* If it's single threaded, it isn't in the list of workqueues. */
+static inline int is_wq_single_threaded(struct workqueue_struct *wq)
+{
+	return wq->singlethread;
+}
+
+static const struct cpumask *wq_cpu_map(struct workqueue_struct *wq)
+{
+	return is_wq_single_threaded(wq)
+		? cpu_singlethread_map : cpu_populated_map;
+}
+
+static
+struct cpu_workqueue_struct *wq_per_cpu(struct workqueue_struct *wq, int cpu)
+{
+	if (unlikely(is_wq_single_threaded(wq)))
+		cpu = singlethread_cpu;
+	return per_cpu_ptr(wq->cpu_wq, cpu);
+}
+
+/*
+ * 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,
+				struct cpu_workqueue_struct *cwq)
+{
+	unsigned long new;
+
+	BUG_ON(!work_pending(work));
+
+	new = (unsigned long) cwq | (1UL << WORK_STRUCT_PENDING);
+	new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work);
+	atomic_long_set(&work->data, new);
+}
+
+static inline
+struct cpu_workqueue_struct *get_wq_data(struct work_struct *work)
+{
+	return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK);
+}
+
+static void insert_work(struct cpu_workqueue_struct *cwq,
+			struct work_struct *work, struct list_head *head)
+{
+	set_wq_data(work, cwq);
+	/*
+	 * Ensure that we get the right work->data if we see the
+	 * result of list_add() below, see try_to_grab_pending().
+	 */
+	smp_wmb();
+	list_add_tail(&work->entry, head);
+	wake_up(&cwq->more_work);
+}
+
+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, &cwq->worklist);
+	spin_unlock_irqrestore(&cwq->lock, flags);
+}
+
+/**
+ * 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 on which it was submitted, but if the CPU dies
+ * it can be processed by another CPU.
+ */
+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, cpu), work);
+		ret = 1;
+	}
+	return ret;
+}
+EXPORT_SYMBOL_GPL(queue_work_on);
+
+static void delayed_work_timer_fn(unsigned long __data)
+{
+	struct delayed_work *dwork = (struct delayed_work *)__data;
+	struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work);
+	struct workqueue_struct *wq = cwq->wq;
+
+	__queue_work(wq_per_cpu(wq, smp_processor_id()), &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 queue_delayed_work(struct workqueue_struct *wq,
+			struct delayed_work *dwork, unsigned long delay)
+{
+	if (delay == 0)
+		return queue_work(wq, &dwork->work);
+
+	return queue_delayed_work_on(-1, wq, dwork, delay);
+}
+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));
+
+		timer_stats_timer_set_start_info(&dwork->timer);
+
+		/* This stores cwq for the moment, for the timer_fn */
+		set_wq_data(work, wq_per_cpu(wq, raw_smp_processor_id()));
+		timer->expires = jiffies + delay;
+		timer->data = (unsigned long)dwork;
+		timer->function = delayed_work_timer_fn;
+
+		if (unlikely(cpu >= 0))
+			add_timer_on(timer, cpu);
+		else
+			add_timer(timer);
+		ret = 1;
+	}
+	return ret;
+}
+EXPORT_SYMBOL_GPL(queue_delayed_work_on);
+
+static void run_workqueue(struct cpu_workqueue_struct *cwq)
+{
+	spin_lock_irq(&cwq->lock);
+	cwq->run_depth++;
+	if (cwq->run_depth > 3) {
+		/* morton gets to eat his hat */
+		printk("%s: recursion depth exceeded: %d\n",
+			__func__, cwq->run_depth);
+		dump_stack();
+	}
+	while (!list_empty(&cwq->worklist)) {
+		struct work_struct *work = list_entry(cwq->worklist.next,
+						struct work_struct, entry);
+		work_func_t f = work->func;
+#ifdef CONFIG_LOCKDEP
+		/*
+		 * It is permissible to free the struct work_struct
+		 * from inside the function that is called from it,
+		 * this we need to take into account for lockdep too.
+		 * To avoid bogus "held lock freed" warnings as well
+		 * as problems when looking into work->lockdep_map,
+		 * make a copy and use that here.
+		 */
+		struct lockdep_map lockdep_map = work->lockdep_map;
+#endif
+
+		cwq->current_work = work;
+		list_del_init(cwq->worklist.next);
+		spin_unlock_irq(&cwq->lock);
+
+		BUG_ON(get_wq_data(work) != cwq);
+		work_clear_pending(work);
+		lock_map_acquire(&cwq->wq->lockdep_map);
+		lock_map_acquire(&lockdep_map);
+		f(work);
+		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: "
+					"%s/0x%08x/%d\n",
+					current->comm, preempt_count(),
+				       	task_pid_nr(current));
+#ifndef DDE_LINUX
+			printk(KERN_ERR "    last function: ");
+			print_symbol("%s\n", (unsigned long)f);
+			debug_show_held_locks(current);
+			dump_stack();
+#endif /* DDE_LINUX */
+		}
+
+		spin_lock_irq(&cwq->lock);
+		cwq->current_work = NULL;
+	}
+	cwq->run_depth--;
+	spin_unlock_irq(&cwq->lock);
+}
+
+static int worker_thread(void *__cwq)
+{
+	struct cpu_workqueue_struct *cwq = __cwq;
+	DEFINE_WAIT(wait);
+
+	if (cwq->wq->freezeable)
+		set_freezable();
+
+	set_user_nice(current, -5);
+
+	for (;;) {
+		prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE);
+		if (!freezing(current) &&
+		    !kthread_should_stop() &&
+		    list_empty(&cwq->worklist))
+			schedule();
+		finish_wait(&cwq->more_work, &wait);
+
+		try_to_freeze();
+
+		if (kthread_should_stop())
+			break;
+
+		run_workqueue(cwq);
+	}
+
+	return 0;
+}
+
+struct wq_barrier {
+	struct work_struct	work;
+	struct completion	done;
+};
+
+static void wq_barrier_func(struct work_struct *work)
+{
+	struct wq_barrier *barr = container_of(work, struct wq_barrier, work);
+	complete(&barr->done);
+}
+
+static void insert_wq_barrier(struct cpu_workqueue_struct *cwq,
+			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, head);
+}
+
+static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq)
+{
+	int active;
+
+	if (cwq->thread == current) {
+		/*
+		 * Probably keventd trying to flush its own queue. So simply run
+		 * it by hand rather than deadlocking.
+		 */
+		run_workqueue(cwq);
+		active = 1;
+	} else {
+		struct wq_barrier barr;
+
+		active = 0;
+		spin_lock_irq(&cwq->lock);
+		if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) {
+			insert_wq_barrier(cwq, &barr, &cwq->worklist);
+			active = 1;
+		}
+		spin_unlock_irq(&cwq->lock);
+
+		if (active)
+			wait_for_completion(&barr.done);
+	}
+
+	return active;
+}
+
+/**
+ * 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.
+ *
+ * We sleep until all works which were queued on entry have been handled,
+ * but we are not livelocked by new incoming ones.
+ *
+ * This function used to run the workqueues itself.  Now we just wait for the
+ * helper threads to do it.
+ */
+void flush_workqueue(struct workqueue_struct *wq)
+{
+	const struct cpumask *cpu_map = wq_cpu_map(wq);
+	int cpu;
+
+	might_sleep();
+	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.
+ */
+static int try_to_grab_pending(struct work_struct *work)
+{
+	struct cpu_workqueue_struct *cwq;
+	int ret = -1;
+
+	if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work)))
+		return 0;
+
+	/*
+	 * The queueing is in progress, or it is already queued. Try to
+	 * steal it from ->worklist without clearing WORK_STRUCT_PENDING.
+	 */
+
+	cwq = get_wq_data(work);
+	if (!cwq)
+		return ret;
+
+	spin_lock_irq(&cwq->lock);
+	if (!list_empty(&work->entry)) {
+		/*
+		 * This work is queued, but perhaps we locked the wrong cwq.
+		 * In that case we must see the new value after rmb(), see
+		 * insert_work()->wmb().
+		 */
+		smp_rmb();
+		if (cwq == get_wq_data(work)) {
+			list_del_init(&work->entry);
+			ret = 1;
+		}
+	}
+	spin_unlock_irq(&cwq->lock);
+
+	return ret;
+}
+
+static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq,
+				struct work_struct *work)
+{
+	struct wq_barrier barr;
+	int running = 0;
+
+	spin_lock_irq(&cwq->lock);
+	if (unlikely(cwq->current_work == work)) {
+		insert_wq_barrier(cwq, &barr, cwq->worklist.next);
+		running = 1;
+	}
+	spin_unlock_irq(&cwq->lock);
+
+	if (unlikely(running))
+		wait_for_completion(&barr.done);
+}
+
+static void wait_on_work(struct work_struct *work)
+{
+	struct cpu_workqueue_struct *cwq;
+	struct workqueue_struct *wq;
+	const struct cpumask *cpu_map;
+	int cpu;
+
+	might_sleep();
+
+	lock_map_acquire(&work->lockdep_map);
+	lock_map_release(&work->lockdep_map);
+
+	cwq = get_wq_data(work);
+	if (!cwq)
+		return;
+
+	wq = cwq->wq;
+	cpu_map = wq_cpu_map(wq);
+
+	for_each_cpu_mask_nr(cpu, *cpu_map)
+		wait_on_cpu_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
+}
+
+static int __cancel_work_timer(struct work_struct *work,
+				struct timer_list* timer)
+{
+	int ret;
+
+	do {
+		ret = (timer && likely(del_timer(timer)));
+		if (!ret)
+			ret = try_to_grab_pending(work);
+		wait_on_work(work);
+	} while (unlikely(ret < 0));
+
+	work_clear_pending(work);
+	return ret;
+}
+
+/**
+ * cancel_work_sync - block until a work_struct's callback has terminated
+ * @work: the work which is to be flushed
+ *
+ * Returns true if @work was pending.
+ *
+ * cancel_work_sync() will cancel the work if it is queued. If the work's
+ * callback appears to be running, cancel_work_sync() will block until it
+ * has completed.
+ *
+ * It is possible to use this function if the work re-queues itself. It can
+ * cancel the work even if it migrates to another workqueue, however in that
+ * case it only guarantees that work->func() has completed on the last queued
+ * workqueue.
+ *
+ * cancel_work_sync(&delayed_work->work) should be used only if ->timer is not
+ * pending, otherwise it goes into a busy-wait loop until the timer expires.
+ *
+ * The caller must ensure that workqueue_struct on which this work was last
+ * queued can't be destroyed before this function returns.
+ */
+int cancel_work_sync(struct work_struct *work)
+{
+	return __cancel_work_timer(work, NULL);
+}
+EXPORT_SYMBOL_GPL(cancel_work_sync);
+
+/**
+ * cancel_delayed_work_sync - reliably kill off a delayed work.
+ * @dwork: the delayed work struct
+ *
+ * Returns true if @dwork was pending.
+ *
+ * It is possible to use this function if @dwork rearms itself via queue_work()
+ * or queue_delayed_work(). See also the comment for cancel_work_sync().
+ */
+int cancel_delayed_work_sync(struct delayed_work *dwork)
+{
+	return __cancel_work_timer(&dwork->work, &dwork->timer);
+}
+EXPORT_SYMBOL(cancel_delayed_work_sync);
+
+static struct workqueue_struct *keventd_wq __read_mostly;
+
+/**
+ * schedule_work - put work task in global workqueue
+ * @work: job to be done
+ *
+ * This puts a job in the kernel-global workqueue.
+ */
+int schedule_work(struct work_struct *work)
+{
+	return queue_work(keventd_wq, 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
+ * @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 schedule_delayed_work(struct delayed_work *dwork,
+					unsigned long 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 delayed_work *dwork, unsigned long delay)
+{
+	return queue_delayed_work_on(cpu, keventd_wq, dwork, delay);
+}
+EXPORT_SYMBOL(schedule_delayed_work_on);
+
+/**
+ * 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.
+ *
+ * schedule_on_each_cpu() is very slow.
+ */
+int schedule_on_each_cpu(work_func_t func)
+{
+	int cpu;
+	struct work_struct *works;
+
+	works = alloc_percpu(struct work_struct);
+	if (!works)
+		return -ENOMEM;
+
+	get_online_cpus();
+	for_each_online_cpu(cpu) {
+		struct work_struct *work = per_cpu_ptr(works, cpu);
+
+		INIT_WORK(work, func);
+		schedule_work_on(cpu, work);
+	}
+	for_each_online_cpu(cpu)
+		flush_work(per_cpu_ptr(works, cpu));
+	put_online_cpus();
+	free_percpu(works);
+	return 0;
+}
+
+void flush_scheduled_work(void)
+{
+	flush_workqueue(keventd_wq);
+}
+EXPORT_SYMBOL(flush_scheduled_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;
+}
+
+int current_is_keventd(void)
+{
+	struct cpu_workqueue_struct *cwq;
+	int cpu = raw_smp_processor_id(); /* preempt-safe: keventd is per-cpu */
+	int ret = 0;
+
+	BUG_ON(!keventd_wq);
+
+	cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu);
+	if (current == cwq->thread)
+		ret = 1;
+
+	return ret;
+
+}
+
+static struct cpu_workqueue_struct *
+init_cpu_workqueue(struct workqueue_struct *wq, int cpu)
+{
+	struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu);
+
+	cwq->wq = wq;
+	spin_lock_init(&cwq->lock);
+	INIT_LIST_HEAD(&cwq->worklist);
+	init_waitqueue_head(&cwq->more_work);
+
+	return cwq;
+}
+
+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_wq_single_threaded(wq) ? "%s" : "%s/%d";
+	struct task_struct *p;
+
+	p = kthread_create(worker_thread, cwq, fmt, wq->name, cpu);
+	/*
+	 * Nobody can add the work_struct to this cwq,
+	 *	if (caller is __create_workqueue)
+	 *		nobody should see this wq
+	 *	else // caller is CPU_UP_PREPARE
+	 *		cpu is not on cpu_online_map
+	 * so we can abort safely.
+	 */
+	if (IS_ERR(p))
+		return PTR_ERR(p);
+	if (cwq->wq->rt)
+		sched_setscheduler_nocheck(p, SCHED_FIFO, &param);
+	cwq->thread = p;
+
+	return 0;
+}
+
+static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
+{
+	struct task_struct *p = cwq->thread;
+
+	if (p != NULL) {
+		if (cpu >= 0)
+			kthread_bind(p, cpu);
+		wake_up_process(p);
+	}
+}
+
+struct workqueue_struct *__create_workqueue_key(const char *name,
+						int singlethread,
+						int freezeable,
+						int rt,
+						struct lock_class_key *key,
+						const char *lock_name)
+{
+	struct workqueue_struct *wq;
+	struct cpu_workqueue_struct *cwq;
+	int err = 0, cpu;
+
+	wq = kzalloc(sizeof(*wq), GFP_KERNEL);
+	if (!wq)
+		return NULL;
+
+	wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct);
+	if (!wq->cpu_wq) {
+		kfree(wq);
+		return NULL;
+	}
+
+	wq->name = 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) {
+		cwq = init_cpu_workqueue(wq, singlethread_cpu);
+		err = create_workqueue_thread(cwq, singlethread_cpu);
+		start_workqueue_thread(cwq, -1);
+	} else {
+		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))
+				continue;
+			err = create_workqueue_thread(cwq, cpu);
+			start_workqueue_thread(cwq, cpu);
+		}
+		cpu_maps_update_done();
+	}
+
+	if (err) {
+		destroy_workqueue(wq);
+		wq = NULL;
+	}
+	return wq;
+}
+EXPORT_SYMBOL_GPL(__create_workqueue_key);
+
+static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq)
+{
+	/*
+	 * Our caller is either destroy_workqueue() or CPU_POST_DEAD,
+	 * cpu_add_remove_lock protects cwq->thread.
+	 */
+	if (cwq->thread == NULL)
+		return;
+
+	lock_map_acquire(&cwq->wq->lockdep_map);
+	lock_map_release(&cwq->wq->lockdep_map);
+
+	flush_cpu_workqueue(cwq);
+	/*
+	 * 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.
+	 * When ->worklist becomes empty it is safe to exit because no
+	 * more work_structs can be queued on this cwq: flush_workqueue
+	 * checks list_empty(), and a "normal" queue_work() can't use
+	 * a dead CPU.
+	 */
+	kthread_stop(cwq->thread);
+	cwq->thread = NULL;
+}
+
+/**
+ * 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)
+{
+	const struct cpumask *cpu_map = wq_cpu_map(wq);
+	int cpu;
+
+	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));
+ 	cpu_maps_update_done();
+
+	free_percpu(wq->cpu_wq);
+	kfree(wq);
+}
+EXPORT_SYMBOL_GPL(destroy_workqueue);
+
+static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
+						unsigned long action,
+						void *hcpu)
+{
+	unsigned int cpu = (unsigned long)hcpu;
+	struct cpu_workqueue_struct *cwq;
+	struct workqueue_struct *wq;
+	int ret = NOTIFY_OK;
+
+	action &= ~CPU_TASKS_FROZEN;
+
+	switch (action) {
+	case CPU_UP_PREPARE:
+		cpumask_set_cpu(cpu, cpu_populated_map);
+	}
+undo:
+	list_for_each_entry(wq, &workqueues, list) {
+		cwq = per_cpu_ptr(wq->cpu_wq, cpu);
+
+		switch (action) {
+		case CPU_UP_PREPARE:
+			if (!create_workqueue_thread(cwq, cpu))
+				break;
+			printk(KERN_ERR "workqueue [%s] for %i failed\n",
+				wq->name, cpu);
+			action = CPU_UP_CANCELED;
+			ret = NOTIFY_BAD;
+			goto undo;
+
+		case CPU_ONLINE:
+			start_workqueue_thread(cwq, cpu);
+			break;
+
+		case CPU_UP_CANCELED:
+			start_workqueue_thread(cwq, -1);
+		case CPU_POST_DEAD:
+			cleanup_workqueue_thread(cwq);
+			break;
+		}
+	}
+
+	switch (action) {
+	case CPU_UP_CANCELED:
+	case CPU_POST_DEAD:
+		cpumask_clear_cpu(cpu, cpu_populated_map);
+	}
+
+	return ret;
+}
+
+#ifdef CONFIG_SMP
+static struct workqueue_struct *work_on_cpu_wq __read_mostly;
+
+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 the value @fn returns.
+ * It is up to the caller to ensure that the cpu doesn't go offline.
+ */
+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;
+	queue_work_on(cpu, work_on_cpu_wq, &wfc.work);
+	flush_work(&wfc.work);
+
+	return wfc.ret;
+}
+EXPORT_SYMBOL_GPL(work_on_cpu);
+#endif /* CONFIG_SMP */
+
+void __init init_workqueues(void)
+{
+	alloc_cpumask_var(&cpu_populated_map, GFP_KERNEL);
+
+	cpumask_copy(cpu_populated_map, cpu_online_mask);
+	singlethread_cpu = cpumask_first(cpu_possible_mask);
+	cpu_singlethread_map = cpumask_of(singlethread_cpu);
+	hotcpu_notifier(workqueue_cpu_callback, 0);
+	keventd_wq = create_workqueue("events");
+	BUG_ON(!keventd_wq);
+#ifdef CONFIG_SMP
+	work_on_cpu_wq = create_workqueue("work_on_cpu");
+	BUG_ON(!work_on_cpu_wq);
+#endif
+}
+
+#ifdef DDE_LINUX
+core_initcall(init_workqueues);
+#endif