Message-Id: <1430103618-10832-6-git-send-email-tazaki@sfc.wide.ad.jp>
Date:	Mon, 27 Apr 2015 12:00:13 +0900
From:	Hajime Tazaki <tazaki@....wide.ad.jp>
To:	linux-arch@...r.kernel.org
Cc:	Hajime Tazaki <tazaki@....wide.ad.jp>,
	Arnd Bergmann <arnd@...db.de>,
	Jonathan Corbet <corbet@....net>,
	Christoph Lameter <cl@...ux.com>,
	Jekka Enberg <penberg@...nel.org>,
	Javid Rientjes <rientjes@...gle.com>,
	Joonsoo Kim <iamjoonsoo.kim@....com>,
	Jndrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
	netdev@...r.kernel.org, linux-mm@...ck.org,
	Jeff Dike <jdike@...toit.com>,
	Richard Weinberger <richard@....at>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Ryo Nakamura <upa@...ena.net>,
	Christoph Paasch <christoph.paasch@...il.com>,
	Mathieu Lacage <mathieu.lacage@...il.com>,
	libos-nuse@...glegroups.com
Subject: [PATCH v4 05/10] lib: context and scheduling functions (kernel glue code) for libos

contexnt primitives of kernel such as soft interupts, scheduling,
tasklet are implemented for libos. these functions eventually call the
functions registered by lib_init() API as well.

Signed-off-by: Hajime Tazaki <tazaki@....wide.ad.jp>
---
 arch/lib/sched.c     | 406 +++++++++++++++++++++++++++++++++++++++++++++++++++
 arch/lib/softirq.c   | 108 ++++++++++++++
 arch/lib/tasklet.c   |  76 ++++++++++
 arch/lib/workqueue.c | 242 ++++++++++++++++++++++++++++++
 4 files changed, 832 insertions(+)
 create mode 100644 arch/lib/sched.c
 create mode 100644 arch/lib/softirq.c
 create mode 100644 arch/lib/tasklet.c
 create mode 100644 arch/lib/workqueue.c

diff --git a/arch/lib/sched.c b/arch/lib/sched.c
new file mode 100644
index 0000000..98a568a
--- /dev/null
+++ b/arch/lib/sched.c
@@ -0,0 +1,406 @@
+/*
+ * glue code for library version of Linux kernel
+ * Copyright (c) 2015 INRIA, Hajime Tazaki
+ *
+ * Author: Mathieu Lacage <mathieu.lacage@...il.com>
+ *         Hajime Tazaki <tazaki@....wide.ad.jp>
+ */
+
+#include <linux/wait.h>
+#include <linux/list.h>
+#include <linux/sched.h>
+#include <linux/nsproxy.h>
+#include <linux/hash.h>
+#include <net/net_namespace.h>
+#include "lib.h"
+#include "sim.h"
+#include "sim-assert.h"
+
+/**
+   called by wait_event macro:
+   - prepare_to_wait
+   - schedule
+   - finish_wait
+ */
+
+struct SimTask *lib_task_create(void *private, unsigned long pid)
+{
+	struct SimTask *task = lib_malloc(sizeof(struct SimTask));
+	struct cred *cred;
+	struct nsproxy *ns;
+	struct user_struct *user;
+	struct thread_info *info;
+	struct pid *kpid;
+
+	if (!task)
+		return NULL;
+	memset(task, 0, sizeof(struct SimTask));
+	cred = lib_malloc(sizeof(struct cred));
+	if (!cred)
+		return NULL;
+	/* XXX: we could optimize away this allocation by sharing it
+	   for all tasks */
+	ns = lib_malloc(sizeof(struct nsproxy));
+	if (!ns)
+		return NULL;
+	user = lib_malloc(sizeof(struct user_struct));
+	if (!user)
+		return NULL;
+	info = alloc_thread_info(&task->kernel_task);
+	if (!info)
+		return NULL;
+	kpid = lib_malloc(sizeof(struct pid));
+	if (!kpid)
+		return NULL;
+	kpid->numbers[0].nr = pid;
+	cred->fsuid = make_kuid(current_user_ns(), 0);
+	cred->fsgid = make_kgid(current_user_ns(), 0);
+	cred->user = user;
+	atomic_set(&cred->usage, 1);
+	info->task = &task->kernel_task;
+	info->preempt_count = 0;
+	info->flags = 0;
+	atomic_set(&ns->count, 1);
+	ns->uts_ns = 0;
+	ns->ipc_ns = 0;
+	ns->mnt_ns = 0;
+	ns->pid_ns_for_children = 0;
+	ns->net_ns = &init_net;
+	task->kernel_task.cred = cred;
+	task->kernel_task.pid = pid;
+	task->kernel_task.pids[PIDTYPE_PID].pid = kpid;
+	task->kernel_task.pids[PIDTYPE_PGID].pid = kpid;
+	task->kernel_task.pids[PIDTYPE_SID].pid = kpid;
+	task->kernel_task.nsproxy = ns;
+	task->kernel_task.stack = info;
+	/* this is a hack. */
+	task->kernel_task.group_leader = &task->kernel_task;
+	task->private = private;
+	return task;
+}
+void lib_task_destroy(struct SimTask *task)
+{
+	lib_free((void *)task->kernel_task.nsproxy);
+	lib_free((void *)task->kernel_task.cred);
+	lib_free((void *)task->kernel_task.cred->user);
+	free_thread_info(task->kernel_task.stack);
+	lib_free(task);
+}
+void *lib_task_get_private(struct SimTask *task)
+{
+	return task->private;
+}
+
+int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
+{
+	struct SimTask *task = lib_task_start((void (*)(void *))fn, arg);
+
+	return task->kernel_task.pid;
+}
+
+struct task_struct *get_current(void)
+{
+	struct SimTask *lib_task = lib_task_current();
+
+	return &lib_task->kernel_task;
+}
+
+struct thread_info *current_thread_info(void)
+{
+	return task_thread_info(get_current());
+}
+struct thread_info *alloc_thread_info(struct task_struct *task)
+{
+	return lib_malloc(sizeof(struct thread_info));
+}
+void free_thread_info(struct thread_info *ti)
+{
+	lib_free(ti);
+}
+
+
+void __put_task_struct(struct task_struct *t)
+{
+	lib_free(t);
+}
+
+void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait)
+{
+	wait->flags &= ~WQ_FLAG_EXCLUSIVE;
+	list_add(&wait->task_list, &q->task_list);
+}
+void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
+{
+	wait->flags |= WQ_FLAG_EXCLUSIVE;
+	list_add_tail(&wait->task_list, &q->task_list);
+}
+void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait)
+{
+	if (wait->task_list.prev != LIST_POISON2)
+		list_del(&wait->task_list);
+}
+void
+prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state)
+{
+	wait->flags |= WQ_FLAG_EXCLUSIVE;
+	if (list_empty(&wait->task_list))
+		list_add_tail(&wait->task_list, &q->task_list);
+	set_current_state(state);
+}
+void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state)
+{
+	unsigned long flags;
+
+	wait->flags &= ~WQ_FLAG_EXCLUSIVE;
+	spin_lock_irqsave(&q->lock, flags);
+	if (list_empty(&wait->task_list))
+		__add_wait_queue(q, wait);
+	set_current_state(state);
+	spin_unlock_irqrestore(&q->lock, flags);
+}
+void finish_wait(wait_queue_head_t *q, wait_queue_t *wait)
+{
+	set_current_state(TASK_RUNNING);
+	if (!list_empty(&wait->task_list))
+		list_del_init(&wait->task_list);
+}
+int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync,
+			     void *key)
+{
+	int ret = default_wake_function(wait, mode, sync, key);
+
+	if (ret && (wait->task_list.prev != LIST_POISON2))
+		list_del_init(&wait->task_list);
+
+	return ret;
+}
+
+int woken_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key)
+{
+	wait->flags |= WQ_FLAG_WOKEN;
+	return default_wake_function(wait, mode, sync, key);
+}
+
+void __init_waitqueue_head(wait_queue_head_t *q, const char *name,
+			   struct lock_class_key *k)
+{
+	INIT_LIST_HEAD(&q->task_list);
+}
+/**
+ * wait_for_completion: - waits for completion of a task
+ * @x:  holds the state of this particular completion
+ *
+ * This waits to be signaled for completion of a specific task. It is NOT
+ * interruptible and there is no timeout.
+ *
+ * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
+ * and interrupt capability. Also see complete().
+ */
+void wait_for_completion(struct completion *x)
+{
+	wait_for_completion_timeout(x, MAX_SCHEDULE_TIMEOUT);
+}
+unsigned long wait_for_completion_timeout(struct completion *x,
+					  unsigned long timeout)
+{
+	if (!x->done) {
+		DECLARE_WAITQUEUE(wait, current);
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		wait.flags |= WQ_FLAG_EXCLUSIVE;
+		list_add_tail(&wait.task_list, &x->wait.task_list);
+		do
+			timeout = schedule_timeout(timeout);
+		while (!x->done && timeout);
+		if (wait.task_list.prev != LIST_POISON2)
+			list_del(&wait.task_list);
+
+		if (!x->done)
+			return timeout;
+	}
+	x->done--;
+	return timeout ? : 1;
+}
+
+/**
+ * __wake_up - wake up threads blocked on a waitqueue.
+ * @q: the waitqueue
+ * @mode: which threads
+ * @nr_exclusive: how many wake-one or wake-many threads to wake up
+ * @key: is directly passed to the wakeup function
+ *
+ * It may be assumed that this function implies a write memory barrier before
+ * changing the task state if and only if any tasks are woken up.
+ */
+void __wake_up(wait_queue_head_t *q, unsigned int mode,
+	       int nr_exclusive, void *key)
+{
+	wait_queue_t *curr, *next;
+
+	list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
+		unsigned flags = curr->flags;
+
+		if (curr->func(curr, mode, 0, key) &&
+		    (flags & WQ_FLAG_EXCLUSIVE) &&
+		    !--nr_exclusive)
+			break;
+	}
+}
+void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
+			int nr_exclusive, void *key)
+{
+	__wake_up(q, mode, nr_exclusive, key);
+}
+int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags,
+			  void *key)
+{
+	struct task_struct *task = (struct task_struct *)curr->private;
+	struct SimTask *lib_task = container_of(task, struct SimTask,
+						kernel_task);
+
+	return lib_task_wakeup(lib_task);
+}
+__sched int bit_wait(struct wait_bit_key *word)
+{
+	if (signal_pending_state(current->state, current))
+		return 1;
+	schedule();
+	return 0;
+}
+int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *arg)
+{
+	struct wait_bit_key *key = arg;
+	struct wait_bit_queue *wait_bit
+		= container_of(wait, struct wait_bit_queue, wait);
+
+	if (wait_bit->key.flags != key->flags ||
+			wait_bit->key.bit_nr != key->bit_nr ||
+			test_bit(key->bit_nr, key->flags))
+		return 0;
+	else
+		return autoremove_wake_function(wait, mode, sync, key);
+}
+void __wake_up_bit(wait_queue_head_t *wq, void *word, int bit)
+{
+	struct wait_bit_key key = __WAIT_BIT_KEY_INITIALIZER(word, bit);
+	if (waitqueue_active(wq))
+		__wake_up(wq, TASK_NORMAL, 1, &key);
+}
+void wake_up_bit(void *word, int bit)
+{
+	/* FIXME */
+	return;
+	__wake_up_bit(bit_waitqueue(word, bit), word, bit);
+}
+wait_queue_head_t *bit_waitqueue(void *word, int bit)
+{
+	const int shift = BITS_PER_LONG == 32 ? 5 : 6;
+	const struct zone *zone = page_zone(virt_to_page(word));
+	unsigned long val = (unsigned long)word << shift | bit;
+
+	return &zone->wait_table[hash_long(val, zone->wait_table_bits)];
+}
+
+
+void schedule(void)
+{
+	lib_task_wait();
+}
+
+static void trampoline(void *context)
+{
+	struct SimTask *task = context;
+
+	lib_task_wakeup(task);
+}
+
+signed long schedule_timeout(signed long timeout)
+{
+	u64 ns;
+	struct SimTask *self;
+
+	if (timeout == MAX_SCHEDULE_TIMEOUT) {
+		lib_task_wait();
+		return MAX_SCHEDULE_TIMEOUT;
+	}
+	lib_assert(timeout >= 0);
+	ns = ((__u64)timeout) * (1000000000 / HZ);
+	self = lib_task_current();
+	lib_event_schedule_ns(ns, &trampoline, self);
+	lib_task_wait();
+	/* we know that we are always perfectly on time. */
+	return 0;
+}
+
+signed long schedule_timeout_uninterruptible(signed long timeout)
+{
+	return schedule_timeout(timeout);
+}
+signed long schedule_timeout_interruptible(signed long timeout)
+{
+	return schedule_timeout(timeout);
+}
+
+void yield(void)
+{
+	lib_task_yield();
+}
+
+void complete_all(struct completion *x)
+{
+	x->done += UINT_MAX / 2;
+	__wake_up(&x->wait, TASK_NORMAL, 0, 0);
+}
+void complete(struct completion *x)
+{
+	x->done++;
+	__wake_up(&x->wait, TASK_NORMAL, 1, 0);
+}
+
+long wait_for_completion_interruptible_timeout(
+	struct completion *x, unsigned long timeout)
+{
+	return wait_for_completion_timeout(x, timeout);
+}
+int wait_for_completion_interruptible(struct completion *x)
+{
+	wait_for_completion_timeout(x, MAX_SCHEDULE_TIMEOUT);
+	return 0;
+}
+int wake_up_process(struct task_struct *tsk)
+{
+	struct SimTask *lib_task =
+		container_of(tsk, struct SimTask, kernel_task);
+
+	return lib_task_wakeup(lib_task);
+}
+int _cond_resched(void)
+{
+	/* we never schedule to decrease latency. */
+	return 0;
+}
+int idle_cpu(int cpu)
+{
+	/* we are never idle: we call this from rcutiny.c and the answer */
+	/* does not matter, really. */
+	return 0;
+}
+
+unsigned long long __attribute__((weak)) sched_clock(void)
+{
+	return (unsigned long long)(jiffies - INITIAL_JIFFIES)
+	       * (NSEC_PER_SEC / HZ);
+}
+
+u64 local_clock(void)
+{
+	return sched_clock();
+}
+
+void __sched schedule_preempt_disabled(void)
+{
+}
+
+void resched_cpu(int cpu)
+{
+	rcu_sched_qs();
+}
diff --git a/arch/lib/softirq.c b/arch/lib/softirq.c
new file mode 100644
index 0000000..3f6363a
--- /dev/null
+++ b/arch/lib/softirq.c
@@ -0,0 +1,108 @@
+/*
+ * glue code for library version of Linux kernel
+ * Copyright (c) 2015 INRIA, Hajime Tazaki
+ *
+ * Author: Mathieu Lacage <mathieu.lacage@...il.com>
+ *         Hajime Tazaki <tazaki@....wide.ad.jp>
+ */
+
+#include <linux/interrupt.h>
+#include "sim-init.h"
+#include "sim.h"
+#include "sim-assert.h"
+
+
+static struct softirq_action softirq_vec[NR_SOFTIRQS];
+static struct SimTask *g_softirq_task = 0;
+static int g_n_raises = 0;
+
+void lib_softirq_wakeup(void)
+{
+	g_n_raises++;
+	lib_task_wakeup(g_softirq_task);
+}
+
+static void softirq_task_function(void *context)
+{
+	while (true) {
+		do_softirq();
+		g_n_raises--;
+		if (g_n_raises == 0 || local_softirq_pending() == 0) {
+			g_n_raises = 0;
+			lib_task_wait();
+		}
+	}
+}
+
+static void ensure_task_created(void)
+{
+	if (g_softirq_task != 0)
+		return;
+	g_softirq_task = lib_task_start(&softirq_task_function, 0);
+}
+
+void open_softirq(int nr, void (*action)(struct softirq_action *))
+{
+	ensure_task_created();
+	softirq_vec[nr].action = action;
+}
+#define MAX_SOFTIRQ_RESTART 10
+
+void do_softirq(void)
+{
+	__u32 pending;
+	int max_restart = MAX_SOFTIRQ_RESTART;
+	struct softirq_action *h;
+
+	pending = local_softirq_pending();
+
+restart:
+	/* Reset the pending bitmask before enabling irqs */
+	set_softirq_pending(0);
+
+	local_irq_enable();
+
+	h = softirq_vec;
+
+	do {
+		if (pending & 1)
+			h->action(h);
+		h++;
+		pending >>= 1;
+	} while (pending);
+
+	local_irq_disable();
+
+	pending = local_softirq_pending();
+	if (pending && --max_restart)
+		goto restart;
+}
+void raise_softirq_irqoff(unsigned int nr)
+{
+	__raise_softirq_irqoff(nr);
+
+	lib_softirq_wakeup();
+}
+void __raise_softirq_irqoff(unsigned int nr)
+{
+	/* trace_softirq_raise(nr); */
+	or_softirq_pending(1UL << nr);
+}
+int __cond_resched_softirq(void)
+{
+	/* tell the caller that we did not need to re-schedule. */
+	return 0;
+}
+void raise_softirq(unsigned int nr)
+{
+	/* copy/paste from kernel/softirq.c */
+	unsigned long flags;
+
+	local_irq_save(flags);
+	raise_softirq_irqoff(nr);
+	local_irq_restore(flags);
+}
+
+void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
+{
+}
diff --git a/arch/lib/tasklet.c b/arch/lib/tasklet.c
new file mode 100644
index 0000000..6cc68f4
--- /dev/null
+++ b/arch/lib/tasklet.c
@@ -0,0 +1,76 @@
+/*
+ * glue code for library version of Linux kernel
+ * Copyright (c) 2015 INRIA, Hajime Tazaki
+ *
+ * Author: Mathieu Lacage <mathieu.lacage@...il.com>
+ *         Hajime Tazaki <tazaki@....wide.ad.jp>
+ */
+
+#include <linux/interrupt.h>
+#include "sim.h"
+#include "sim-assert.h"
+
+void tasklet_init(struct tasklet_struct *t,
+		  void (*func)(unsigned long), unsigned long data)
+{
+	t->next = NULL;
+	t->state = 0;
+	atomic_set(&t->count, 0);
+	t->func = func;
+	t->data = data;
+}
+
+void tasklet_kill(struct tasklet_struct *t)
+{
+	/* theoretically, called from user context */
+	while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) {
+		do
+			lib_task_yield();
+		while (test_bit(TASKLET_STATE_SCHED, &t->state));
+	}
+	clear_bit(TASKLET_STATE_SCHED, &t->state);
+}
+struct tasklet_struct *g_sched_events = NULL;
+static void run_tasklet_softirq(struct softirq_action *h)
+{
+	/* while (!list_empty (&g_sched_events)) */
+	/*   { */
+	struct tasklet_struct *tasklet = g_sched_events;
+
+	if (atomic_read(&tasklet->count) == 0) {
+		/* this tasklet is enabled so, we run it. */
+		test_and_clear_bit(TASKLET_STATE_SCHED, &tasklet->state);
+		tasklet->func(tasklet->data);
+	}
+	/* } */
+}
+static void ensure_softirq_opened(void)
+{
+	static bool opened = false;
+
+	if (opened)
+		return;
+	opened = true;
+	open_softirq(TASKLET_SOFTIRQ, run_tasklet_softirq);
+}
+static void trampoline(void *context)
+{
+	ensure_softirq_opened();
+	struct tasklet_struct *tasklet = context;
+	/* allow the tasklet to re-schedule itself */
+	lib_assert(tasklet->next != 0);
+	tasklet->next = 0;
+	g_sched_events = tasklet;
+	raise_softirq(TASKLET_SOFTIRQ);
+}
+void __tasklet_schedule(struct tasklet_struct *t)
+{
+	void *event;
+
+	/* Note: no need to set TASKLET_STATE_SCHED because
+	   it is set by caller. */
+	lib_assert(t->next == 0);
+	/* run the tasklet at the next immediately available opportunity. */
+	event = lib_event_schedule_ns(0, &trampoline, t);
+	t->next = event;
+}
diff --git a/arch/lib/workqueue.c b/arch/lib/workqueue.c
new file mode 100644
index 0000000..bd0e9c5
--- /dev/null
+++ b/arch/lib/workqueue.c
@@ -0,0 +1,242 @@
+/*
+ * glue code for library version of Linux kernel
+ * Copyright (c) 2015 INRIA, Hajime Tazaki
+ *
+ * Author: Mathieu Lacage <mathieu.lacage@...il.com>
+ *         Hajime Tazaki <tazaki@....wide.ad.jp>
+ */
+
+#include <linux/workqueue.h>
+#include <linux/slab.h>
+#include "sim.h"
+#include "sim-assert.h"
+
+/* copy from kernel/workqueue.c */
+typedef unsigned long mayday_mask_t;
+struct workqueue_struct {
+	unsigned int flags;                     /* W: WQ_* flags */
+	union {
+		struct cpu_workqueue_struct __percpu *pcpu;
+		struct cpu_workqueue_struct *single;
+		unsigned long v;
+	} cpu_wq;                               /* I: cwq's */
+	struct list_head list;                  /* W: list of all workqueues */
+
+	struct mutex flush_mutex;               /* protects wq flushing */
+	int work_color;                         /* F: current work color */
+	int flush_color;                        /* F: current flush color */
+	atomic_t nr_cwqs_to_flush;              /* flush in progress */
+	struct wq_flusher *first_flusher;       /* F: first flusher */
+	struct list_head flusher_queue;         /* F: flush waiters */
+	struct list_head flusher_overflow;      /* F: flush overflow list */
+
+	mayday_mask_t mayday_mask;              /* cpus requesting rescue */
+	struct worker *rescuer;                 /* I: rescue worker */
+
+	int nr_drainers;                        /* W: drain in progress */
+	int saved_max_active;                   /* W: saved cwq max_active */
+#ifdef CONFIG_LOCKDEP
+	struct lockdep_map lockdep_map;
+#endif
+	char name[];                            /* I: workqueue name */
+};
+
+struct wq_barrier {
+	struct SimTask *waiter;
+	struct workqueue_struct wq;
+};
+
+static void
+workqueue_function(void *context)
+{
+	struct workqueue_struct *wq = context;
+
+	while (true) {
+		lib_task_wait();
+		while (!list_empty(&wq->list)) {
+			struct work_struct *work =
+				list_first_entry(&wq->list, struct work_struct,
+						entry);
+			work_func_t f = work->func;
+
+			if (work->entry.prev != LIST_POISON2) {
+				list_del_init(&work->entry);
+				clear_bit(WORK_STRUCT_PENDING_BIT,
+					  work_data_bits(work));
+				f(work);
+			}
+		}
+	}
+}
+
+static struct SimTask *workqueue_task(struct workqueue_struct *wq)
+{
+	struct wq_barrier *barr = container_of(wq, struct wq_barrier, wq);
+
+	if (barr->waiter == 0)
+		barr->waiter = lib_task_start(&workqueue_function, wq);
+	return barr->waiter;
+}
+
+static int flush_entry(struct workqueue_struct *wq, struct list_head *prev)
+{
+	int active = 0;
+
+	if (!list_empty(&wq->list)) {
+		active = 1;
+		lib_task_wakeup(workqueue_task(wq));
+		/* XXX: should wait for completion? but this will block
+		   and init won't return.. */
+		/* lib_task_wait (); */
+	}
+
+	return active;
+}
+
+void delayed_work_timer_fn(unsigned long data)
+{
+	struct delayed_work *dwork = (struct delayed_work *)data;
+	struct work_struct *work = &dwork->work;
+
+	list_add_tail(&work->entry, &dwork->wq->list);
+	lib_task_wakeup(workqueue_task(dwork->wq));
+}
+
+bool queue_work_on(int cpu, struct workqueue_struct *wq,
+		   struct work_struct *work)
+{
+	int ret = 0;
+
+	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+		list_add_tail(&work->entry, &wq->list);
+		lib_task_wakeup(workqueue_task(wq));
+		ret = 1;
+	}
+	return ret;
+}
+
+void flush_scheduled_work(void)
+{
+	flush_entry(system_wq, system_wq->list.prev);
+}
+bool flush_work(struct work_struct *work)
+{
+	return flush_entry(system_wq, &work->entry);
+}
+void flush_workqueue(struct workqueue_struct *wq)
+{
+	flush_entry(wq, wq->list.prev);
+}
+bool cancel_work_sync(struct work_struct *work)
+{
+	int retval = 0;
+
+	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)))
+		/* work was not yet queued */
+		return 0;
+	if (!list_empty(&work->entry)) {
+		/* work was queued. now unqueued. */
+		if (work->entry.prev != LIST_POISON2) {
+			list_del_init(&work->entry);
+			clear_bit(WORK_STRUCT_PENDING_BIT,
+				  work_data_bits(work));
+			retval = 1;
+		}
+	}
+	return retval;
+}
+bool 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 (delay == 0)
+		return queue_work(wq, work);
+
+	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+		lib_assert(!timer_pending(timer));
+		dwork->wq = wq;
+		/* This stores cwq for the moment, for the timer_fn */
+		timer->expires = jiffies + delay;
+		timer->data = (unsigned long)dwork;
+		timer->function = delayed_work_timer_fn;
+		add_timer(timer);
+		ret = 1;
+	}
+	return ret;
+}
+bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
+			 struct delayed_work *dwork, unsigned long delay)
+{
+	del_timer(&dwork->timer);
+	__clear_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&dwork->work));
+	return queue_delayed_work(wq, dwork, delay);
+}
+bool cancel_delayed_work(struct delayed_work *dwork)
+{
+	del_timer(&dwork->timer);
+	return cancel_work_sync(&dwork->work);
+}
+
+struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
+					       unsigned int flags,
+					       int max_active,
+					       struct lock_class_key *key,
+					       const char *lock_name, ...)
+{
+	va_list args, args1;
+	struct wq_barrier *barr;
+	struct workqueue_struct *wq;
+	size_t namelen;
+
+	/* determine namelen, allocate wq and format name */
+	va_start(args, lock_name);
+	va_copy(args1, args);
+	namelen = vsnprintf(NULL, 0, fmt, args) + 1;
+
+	barr = kzalloc(sizeof(*barr) + namelen, GFP_KERNEL);
+	if (!barr)
+		goto err;
+	barr->waiter = 0;
+	wq = &barr->wq;
+
+	vsnprintf(wq->name, namelen, fmt, args1);
+	va_end(args);
+	va_end(args1);
+
+	max_active = max_active ? : WQ_DFL_ACTIVE;
+	/* init wq */
+	wq->flags = flags;
+	wq->saved_max_active = max_active;
+	mutex_init(&wq->flush_mutex);
+	atomic_set(&wq->nr_cwqs_to_flush, 0);
+	INIT_LIST_HEAD(&wq->flusher_queue);
+	INIT_LIST_HEAD(&wq->flusher_overflow);
+
+	lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
+	INIT_LIST_HEAD(&wq->list);
+
+	/* start waiter task */
+	workqueue_task(wq);
+	return wq;
+err:
+	if (barr)
+		kfree(barr);
+	return NULL;
+}
+
+struct workqueue_struct *system_wq __read_mostly;
+struct workqueue_struct *system_power_efficient_wq __read_mostly;
+/* from linux/workqueue.h */
+#define system_nrt_wq                   __system_nrt_wq()
+
+static int __init init_workqueues(void)
+{
+	system_wq = alloc_workqueue("events", 0, 0);
+	system_power_efficient_wq = alloc_workqueue("events_power_efficient",
+						    WQ_POWER_EFFICIENT, 0);
+	return 0;
+}
+early_initcall(init_workqueues);
-- 
2.1.0

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