Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1119 insertions, 0 deletions

diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
new file mode 100644
index 00000000000..c06614d0e31
--- /dev/null
+++ b/net/sunrpc/sched.c
@@ -0,0 +1,1119 @@
+/*
+ * linux/net/sunrpc/sched.c
+ *
+ * Scheduling for synchronous and asynchronous RPC requests.
+ *
+ * Copyright (C) 1996 Olaf Kirch, <okir@monad.swb.de>
+ * 
+ * TCP NFS related read + write fixes
+ * (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
+ */
+
+#include <linux/module.h>
+
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/mempool.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/spinlock.h>
+
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/xprt.h>
+
+#ifdef RPC_DEBUG
+#define RPCDBG_FACILITY		RPCDBG_SCHED
+#define RPC_TASK_MAGIC_ID	0xf00baa
+static int			rpc_task_id;
+#endif
+
+/*
+ * RPC slabs and memory pools
+ */
+#define RPC_BUFFER_MAXSIZE	(2048)
+#define RPC_BUFFER_POOLSIZE	(8)
+#define RPC_TASK_POOLSIZE	(8)
+static kmem_cache_t	*rpc_task_slabp;
+static kmem_cache_t	*rpc_buffer_slabp;
+static mempool_t	*rpc_task_mempool;
+static mempool_t	*rpc_buffer_mempool;
+
+static void			__rpc_default_timer(struct rpc_task *task);
+static void			rpciod_killall(void);
+static void			rpc_free(struct rpc_task *task);
+
+static void			rpc_async_schedule(void *);
+
+/*
+ * RPC tasks that create another task (e.g. for contacting the portmapper)
+ * will wait on this queue for their child's completion
+ */
+static RPC_WAITQ(childq, "childq");
+
+/*
+ * RPC tasks sit here while waiting for conditions to improve.
+ */
+static RPC_WAITQ(delay_queue, "delayq");
+
+/*
+ * All RPC tasks are linked into this list
+ */
+static LIST_HEAD(all_tasks);
+
+/*
+ * rpciod-related stuff
+ */
+static DECLARE_MUTEX(rpciod_sema);
+static unsigned int		rpciod_users;
+static struct workqueue_struct *rpciod_workqueue;
+
+/*
+ * Spinlock for other critical sections of code.
+ */
+static DEFINE_SPINLOCK(rpc_sched_lock);
+
+/*
+ * Disable the timer for a given RPC task. Should be called with
+ * queue->lock and bh_disabled in order to avoid races within
+ * rpc_run_timer().
+ */
+static inline void
+__rpc_disable_timer(struct rpc_task *task)
+{
+	dprintk("RPC: %4d disabling timer\n", task->tk_pid);
+	task->tk_timeout_fn = NULL;
+	task->tk_timeout = 0;
+}
+
+/*
+ * Run a timeout function.
+ * We use the callback in order to allow __rpc_wake_up_task()
+ * and friends to disable the timer synchronously on SMP systems
+ * without calling del_timer_sync(). The latter could cause a
+ * deadlock if called while we're holding spinlocks...
+ */
+static void rpc_run_timer(struct rpc_task *task)
+{
+	void (*callback)(struct rpc_task *);
+
+	callback = task->tk_timeout_fn;
+	task->tk_timeout_fn = NULL;
+	if (callback && RPC_IS_QUEUED(task)) {
+		dprintk("RPC: %4d running timer\n", task->tk_pid);
+		callback(task);
+	}
+	smp_mb__before_clear_bit();
+	clear_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate);
+	smp_mb__after_clear_bit();
+}
+
+/*
+ * Set up a timer for the current task.
+ */
+static inline void
+__rpc_add_timer(struct rpc_task *task, rpc_action timer)
+{
+	if (!task->tk_timeout)
+		return;
+
+	dprintk("RPC: %4d setting alarm for %lu ms\n",
+			task->tk_pid, task->tk_timeout * 1000 / HZ);
+
+	if (timer)
+		task->tk_timeout_fn = timer;
+	else
+		task->tk_timeout_fn = __rpc_default_timer;
+	set_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate);
+	mod_timer(&task->tk_timer, jiffies + task->tk_timeout);
+}
+
+/*
+ * Delete any timer for the current task. Because we use del_timer_sync(),
+ * this function should never be called while holding queue->lock.
+ */
+static void
+rpc_delete_timer(struct rpc_task *task)
+{
+	if (RPC_IS_QUEUED(task))
+		return;
+	if (test_and_clear_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate)) {
+		del_singleshot_timer_sync(&task->tk_timer);
+		dprintk("RPC: %4d deleting timer\n", task->tk_pid);
+	}
+}
+
+/*
+ * Add new request to a priority queue.
+ */
+static void __rpc_add_wait_queue_priority(struct rpc_wait_queue *queue, struct rpc_task *task)
+{
+	struct list_head *q;
+	struct rpc_task *t;
+
+	INIT_LIST_HEAD(&task->u.tk_wait.links);
+	q = &queue->tasks[task->tk_priority];
+	if (unlikely(task->tk_priority > queue->maxpriority))
+		q = &queue->tasks[queue->maxpriority];
+	list_for_each_entry(t, q, u.tk_wait.list) {
+		if (t->tk_cookie == task->tk_cookie) {
+			list_add_tail(&task->u.tk_wait.list, &t->u.tk_wait.links);
+			return;
+		}
+	}
+	list_add_tail(&task->u.tk_wait.list, q);
+}
+
+/*
+ * Add new request to wait queue.
+ *
+ * Swapper tasks always get inserted at the head of the queue.
+ * This should avoid many nasty memory deadlocks and hopefully
+ * improve overall performance.
+ * Everyone else gets appended to the queue to ensure proper FIFO behavior.
+ */
+static void __rpc_add_wait_queue(struct rpc_wait_queue *queue, struct rpc_task *task)
+{
+	BUG_ON (RPC_IS_QUEUED(task));
+
+	if (RPC_IS_PRIORITY(queue))
+		__rpc_add_wait_queue_priority(queue, task);
+	else if (RPC_IS_SWAPPER(task))
+		list_add(&task->u.tk_wait.list, &queue->tasks[0]);
+	else
+		list_add_tail(&task->u.tk_wait.list, &queue->tasks[0]);
+	task->u.tk_wait.rpc_waitq = queue;
+	rpc_set_queued(task);
+
+	dprintk("RPC: %4d added to queue %p \"%s\"\n",
+				task->tk_pid, queue, rpc_qname(queue));
+}
+
+/*
+ * Remove request from a priority queue.
+ */
+static void __rpc_remove_wait_queue_priority(struct rpc_task *task)
+{
+	struct rpc_task *t;
+
+	if (!list_empty(&task->u.tk_wait.links)) {
+		t = list_entry(task->u.tk_wait.links.next, struct rpc_task, u.tk_wait.list);
+		list_move(&t->u.tk_wait.list, &task->u.tk_wait.list);
+		list_splice_init(&task->u.tk_wait.links, &t->u.tk_wait.links);
+	}
+	list_del(&task->u.tk_wait.list);
+}
+
+/*
+ * Remove request from queue.
+ * Note: must be called with spin lock held.
+ */
+static void __rpc_remove_wait_queue(struct rpc_task *task)
+{
+	struct rpc_wait_queue *queue;
+	queue = task->u.tk_wait.rpc_waitq;
+
+	if (RPC_IS_PRIORITY(queue))
+		__rpc_remove_wait_queue_priority(task);
+	else
+		list_del(&task->u.tk_wait.list);
+	dprintk("RPC: %4d removed from queue %p \"%s\"\n",
+				task->tk_pid, queue, rpc_qname(queue));
+}
+
+static inline void rpc_set_waitqueue_priority(struct rpc_wait_queue *queue, int priority)
+{
+	queue->priority = priority;
+	queue->count = 1 << (priority * 2);
+}
+
+static inline void rpc_set_waitqueue_cookie(struct rpc_wait_queue *queue, unsigned long cookie)
+{
+	queue->cookie = cookie;
+	queue->nr = RPC_BATCH_COUNT;
+}
+
+static inline void rpc_reset_waitqueue_priority(struct rpc_wait_queue *queue)
+{
+	rpc_set_waitqueue_priority(queue, queue->maxpriority);
+	rpc_set_waitqueue_cookie(queue, 0);
+}
+
+static void __rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname, int maxprio)
+{
+	int i;
+
+	spin_lock_init(&queue->lock);
+	for (i = 0; i < ARRAY_SIZE(queue->tasks); i++)
+		INIT_LIST_HEAD(&queue->tasks[i]);
+	queue->maxpriority = maxprio;
+	rpc_reset_waitqueue_priority(queue);
+#ifdef RPC_DEBUG
+	queue->name = qname;
+#endif
+}
+
+void rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname)
+{
+	__rpc_init_priority_wait_queue(queue, qname, RPC_PRIORITY_HIGH);
+}
+
+void rpc_init_wait_queue(struct rpc_wait_queue *queue, const char *qname)
+{
+	__rpc_init_priority_wait_queue(queue, qname, 0);
+}
+EXPORT_SYMBOL(rpc_init_wait_queue);
+
+/*
+ * Make an RPC task runnable.
+ *
+ * Note: If the task is ASYNC, this must be called with 
+ * the spinlock held to protect the wait queue operation.
+ */
+static void rpc_make_runnable(struct rpc_task *task)
+{
+	int do_ret;
+
+	BUG_ON(task->tk_timeout_fn);
+	do_ret = rpc_test_and_set_running(task);
+	rpc_clear_queued(task);
+	if (do_ret)
+		return;
+	if (RPC_IS_ASYNC(task)) {
+		int status;
+
+		INIT_WORK(&task->u.tk_work, rpc_async_schedule, (void *)task);
+		status = queue_work(task->tk_workqueue, &task->u.tk_work);
+		if (status < 0) {
+			printk(KERN_WARNING "RPC: failed to add task to queue: error: %d!\n", status);
+			task->tk_status = status;
+			return;
+		}
+	} else
+		wake_up(&task->u.tk_wait.waitq);
+}
+
+/*
+ * Place a newly initialized task on the workqueue.
+ */
+static inline void
+rpc_schedule_run(struct rpc_task *task)
+{
+	/* Don't run a child twice! */
+	if (RPC_IS_ACTIVATED(task))
+		return;
+	task->tk_active = 1;
+	rpc_make_runnable(task);
+}
+
+/*
+ * Prepare for sleeping on a wait queue.
+ * By always appending tasks to the list we ensure FIFO behavior.
+ * NB: An RPC task will only receive interrupt-driven events as long
+ * as it's on a wait queue.
+ */
+static void __rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
+			rpc_action action, rpc_action timer)
+{
+	dprintk("RPC: %4d sleep_on(queue \"%s\" time %ld)\n", task->tk_pid,
+				rpc_qname(q), jiffies);
+
+	if (!RPC_IS_ASYNC(task) && !RPC_IS_ACTIVATED(task)) {
+		printk(KERN_ERR "RPC: Inactive synchronous task put to sleep!\n");
+		return;
+	}
+
+	/* Mark the task as being activated if so needed */
+	if (!RPC_IS_ACTIVATED(task))
+		task->tk_active = 1;
+
+	__rpc_add_wait_queue(q, task);
+
+	BUG_ON(task->tk_callback != NULL);
+	task->tk_callback = action;
+	__rpc_add_timer(task, timer);
+}
+
+void rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
+				rpc_action action, rpc_action timer)
+{
+	/*
+	 * Protect the queue operations.
+	 */
+	spin_lock_bh(&q->lock);
+	__rpc_sleep_on(q, task, action, timer);
+	spin_unlock_bh(&q->lock);
+}
+
+/**
+ * __rpc_do_wake_up_task - wake up a single rpc_task
+ * @task: task to be woken up
+ *
+ * Caller must hold queue->lock, and have cleared the task queued flag.
+ */
+static void __rpc_do_wake_up_task(struct rpc_task *task)
+{
+	dprintk("RPC: %4d __rpc_wake_up_task (now %ld)\n", task->tk_pid, jiffies);
+
+#ifdef RPC_DEBUG
+	BUG_ON(task->tk_magic != RPC_TASK_MAGIC_ID);
+#endif
+	/* Has the task been executed yet? If not, we cannot wake it up! */
+	if (!RPC_IS_ACTIVATED(task)) {
+		printk(KERN_ERR "RPC: Inactive task (%p) being woken up!\n", task);
+		return;
+	}
+
+	__rpc_disable_timer(task);
+	__rpc_remove_wait_queue(task);
+
+	rpc_make_runnable(task);
+
+	dprintk("RPC:      __rpc_wake_up_task done\n");
+}
+
+/*
+ * Wake up the specified task
+ */
+static void __rpc_wake_up_task(struct rpc_task *task)
+{
+	if (rpc_start_wakeup(task)) {
+		if (RPC_IS_QUEUED(task))
+			__rpc_do_wake_up_task(task);
+		rpc_finish_wakeup(task);
+	}
+}
+
+/*
+ * Default timeout handler if none specified by user
+ */
+static void
+__rpc_default_timer(struct rpc_task *task)
+{
+	dprintk("RPC: %d timeout (default timer)\n", task->tk_pid);
+	task->tk_status = -ETIMEDOUT;
+	rpc_wake_up_task(task);
+}
+
+/*
+ * Wake up the specified task
+ */
+void rpc_wake_up_task(struct rpc_task *task)
+{
+	if (rpc_start_wakeup(task)) {
+		if (RPC_IS_QUEUED(task)) {
+			struct rpc_wait_queue *queue = task->u.tk_wait.rpc_waitq;
+
+			spin_lock_bh(&queue->lock);
+			__rpc_do_wake_up_task(task);
+			spin_unlock_bh(&queue->lock);
+		}
+		rpc_finish_wakeup(task);
+	}
+}
+
+/*
+ * Wake up the next task on a priority queue.
+ */
+static struct rpc_task * __rpc_wake_up_next_priority(struct rpc_wait_queue *queue)
+{
+	struct list_head *q;
+	struct rpc_task *task;
+
+	/*
+	 * Service a batch of tasks from a single cookie.
+	 */
+	q = &queue->tasks[queue->priority];
+	if (!list_empty(q)) {
+		task = list_entry(q->next, struct rpc_task, u.tk_wait.list);
+		if (queue->cookie == task->tk_cookie) {
+			if (--queue->nr)
+				goto out;
+			list_move_tail(&task->u.tk_wait.list, q);
+		}
+		/*
+		 * Check if we need to switch queues.
+		 */
+		if (--queue->count)
+			goto new_cookie;
+	}
+
+	/*
+	 * Service the next queue.
+	 */
+	do {
+		if (q == &queue->tasks[0])
+			q = &queue->tasks[queue->maxpriority];
+		else
+			q = q - 1;
+		if (!list_empty(q)) {
+			task = list_entry(q->next, struct rpc_task, u.tk_wait.list);
+			goto new_queue;
+		}
+	} while (q != &queue->tasks[queue->priority]);
+
+	rpc_reset_waitqueue_priority(queue);
+	return NULL;
+
+new_queue:
+	rpc_set_waitqueue_priority(queue, (unsigned int)(q - &queue->tasks[0]));
+new_cookie:
+	rpc_set_waitqueue_cookie(queue, task->tk_cookie);
+out:
+	__rpc_wake_up_task(task);
+	return task;
+}
+
+/*
+ * Wake up the next task on the wait queue.
+ */
+struct rpc_task * rpc_wake_up_next(struct rpc_wait_queue *queue)
+{
+	struct rpc_task	*task = NULL;
+
+	dprintk("RPC:      wake_up_next(%p \"%s\")\n", queue, rpc_qname(queue));
+	spin_lock_bh(&queue->lock);
+	if (RPC_IS_PRIORITY(queue))
+		task = __rpc_wake_up_next_priority(queue);
+	else {
+		task_for_first(task, &queue->tasks[0])
+			__rpc_wake_up_task(task);
+	}
+	spin_unlock_bh(&queue->lock);
+
+	return task;
+}
+
+/**
+ * rpc_wake_up - wake up all rpc_tasks
+ * @queue: rpc_wait_queue on which the tasks are sleeping
+ *
+ * Grabs queue->lock
+ */
+void rpc_wake_up(struct rpc_wait_queue *queue)
+{
+	struct rpc_task *task;
+
+	struct list_head *head;
+	spin_lock_bh(&queue->lock);
+	head = &queue->tasks[queue->maxpriority];
+	for (;;) {
+		while (!list_empty(head)) {
+			task = list_entry(head->next, struct rpc_task, u.tk_wait.list);
+			__rpc_wake_up_task(task);
+		}
+		if (head == &queue->tasks[0])
+			break;
+		head--;
+	}
+	spin_unlock_bh(&queue->lock);
+}
+
+/**
+ * rpc_wake_up_status - wake up all rpc_tasks and set their status value.
+ * @queue: rpc_wait_queue on which the tasks are sleeping
+ * @status: status value to set
+ *
+ * Grabs queue->lock
+ */
+void rpc_wake_up_status(struct rpc_wait_queue *queue, int status)
+{
+	struct list_head *head;
+	struct rpc_task *task;
+
+	spin_lock_bh(&queue->lock);
+	head = &queue->tasks[queue->maxpriority];
+	for (;;) {
+		while (!list_empty(head)) {
+			task = list_entry(head->next, struct rpc_task, u.tk_wait.list);
+			task->tk_status = status;
+			__rpc_wake_up_task(task);
+		}
+		if (head == &queue->tasks[0])
+			break;
+		head--;
+	}
+	spin_unlock_bh(&queue->lock);
+}
+
+/*
+ * Run a task at a later time
+ */
+static void	__rpc_atrun(struct rpc_task *);
+void
+rpc_delay(struct rpc_task *task, unsigned long delay)
+{
+	task->tk_timeout = delay;
+	rpc_sleep_on(&delay_queue, task, NULL, __rpc_atrun);
+}
+
+static void
+__rpc_atrun(struct rpc_task *task)
+{
+	task->tk_status = 0;
+	rpc_wake_up_task(task);
+}
+
+/*
+ * This is the RPC `scheduler' (or rather, the finite state machine).
+ */
+static int __rpc_execute(struct rpc_task *task)
+{
+	int		status = 0;
+
+	dprintk("RPC: %4d rpc_execute flgs %x\n",
+				task->tk_pid, task->tk_flags);
+
+	BUG_ON(RPC_IS_QUEUED(task));
+
+ restarted:
+	while (1) {
+		/*
+		 * Garbage collection of pending timers...
+		 */
+		rpc_delete_timer(task);
+
+		/*
+		 * Execute any pending callback.
+		 */
+		if (RPC_DO_CALLBACK(task)) {
+			/* Define a callback save pointer */
+			void (*save_callback)(struct rpc_task *);
+	
+			/* 
+			 * If a callback exists, save it, reset it,
+			 * call it.
+			 * The save is needed to stop from resetting
+			 * another callback set within the callback handler
+			 * - Dave
+			 */
+			save_callback=task->tk_callback;
+			task->tk_callback=NULL;
+			lock_kernel();
+			save_callback(task);
+			unlock_kernel();
+		}
+
+		/*
+		 * Perform the next FSM step.
+		 * tk_action may be NULL when the task has been killed
+		 * by someone else.
+		 */
+		if (!RPC_IS_QUEUED(task)) {
+			if (!task->tk_action)
+				break;
+			lock_kernel();
+			task->tk_action(task);
+			unlock_kernel();
+		}
+
+		/*
+		 * Lockless check for whether task is sleeping or not.
+		 */
+		if (!RPC_IS_QUEUED(task))
+			continue;
+		rpc_clear_running(task);
+		if (RPC_IS_ASYNC(task)) {
+			/* Careful! we may have raced... */
+			if (RPC_IS_QUEUED(task))
+				return 0;
+			if (rpc_test_and_set_running(task))
+				return 0;
+			continue;
+		}
+
+		/* sync task: sleep here */
+		dprintk("RPC: %4d sync task going to sleep\n", task->tk_pid);
+		if (RPC_TASK_UNINTERRUPTIBLE(task)) {
+			__wait_event(task->u.tk_wait.waitq, !RPC_IS_QUEUED(task));
+		} else {
+			__wait_event_interruptible(task->u.tk_wait.waitq, !RPC_IS_QUEUED(task), status);
+			/*
+			 * When a sync task receives a signal, it exits with
+			 * -ERESTARTSYS. In order to catch any callbacks that
+			 * clean up after sleeping on some queue, we don't
+			 * break the loop here, but go around once more.
+			 */
+			if (status == -ERESTARTSYS) {
+				dprintk("RPC: %4d got signal\n", task->tk_pid);
+				task->tk_flags |= RPC_TASK_KILLED;
+				rpc_exit(task, -ERESTARTSYS);
+				rpc_wake_up_task(task);
+			}
+		}
+		rpc_set_running(task);
+		dprintk("RPC: %4d sync task resuming\n", task->tk_pid);
+	}
+
+	if (task->tk_exit) {
+		lock_kernel();
+		task->tk_exit(task);
+		unlock_kernel();
+		/* If tk_action is non-null, the user wants us to restart */
+		if (task->tk_action) {
+			if (!RPC_ASSASSINATED(task)) {
+				/* Release RPC slot and buffer memory */
+				if (task->tk_rqstp)
+					xprt_release(task);
+				rpc_free(task);
+				goto restarted;
+			}
+			printk(KERN_ERR "RPC: dead task tries to walk away.\n");
+		}
+	}
+
+	dprintk("RPC: %4d exit() = %d\n", task->tk_pid, task->tk_status);
+	status = task->tk_status;
+
+	/* Release all resources associated with the task */
+	rpc_release_task(task);
+	return status;
+}
+
+/*
+ * User-visible entry point to the scheduler.
+ *
+ * This may be called recursively if e.g. an async NFS task updates
+ * the attributes and finds that dirty pages must be flushed.
+ * NOTE: Upon exit of this function the task is guaranteed to be
+ *	 released. In particular note that tk_release() will have
+ *	 been called, so your task memory may have been freed.
+ */
+int
+rpc_execute(struct rpc_task *task)
+{
+	BUG_ON(task->tk_active);
+
+	task->tk_active = 1;
+	rpc_set_running(task);
+	return __rpc_execute(task);
+}
+
+static void rpc_async_schedule(void *arg)
+{
+	__rpc_execute((struct rpc_task *)arg);
+}
+
+/*
+ * Allocate memory for RPC purposes.
+ *
+ * We try to ensure that some NFS reads and writes can always proceed
+ * by using a mempool when allocating 'small' buffers.
+ * In order to avoid memory starvation triggering more writebacks of
+ * NFS requests, we use GFP_NOFS rather than GFP_KERNEL.
+ */
+void *
+rpc_malloc(struct rpc_task *task, size_t size)
+{
+	int	gfp;
+
+	if (task->tk_flags & RPC_TASK_SWAPPER)
+		gfp = GFP_ATOMIC;
+	else
+		gfp = GFP_NOFS;
+
+	if (size > RPC_BUFFER_MAXSIZE) {
+		task->tk_buffer =  kmalloc(size, gfp);
+		if (task->tk_buffer)
+			task->tk_bufsize = size;
+	} else {
+		task->tk_buffer =  mempool_alloc(rpc_buffer_mempool, gfp);
+		if (task->tk_buffer)
+			task->tk_bufsize = RPC_BUFFER_MAXSIZE;
+	}
+	return task->tk_buffer;
+}
+
+static void
+rpc_free(struct rpc_task *task)
+{
+	if (task->tk_buffer) {
+		if (task->tk_bufsize == RPC_BUFFER_MAXSIZE)
+			mempool_free(task->tk_buffer, rpc_buffer_mempool);
+		else
+			kfree(task->tk_buffer);
+		task->tk_buffer = NULL;
+		task->tk_bufsize = 0;
+	}
+}
+
+/*
+ * Creation and deletion of RPC task structures
+ */
+void rpc_init_task(struct rpc_task *task, struct rpc_clnt *clnt, rpc_action callback, int flags)
+{
+	memset(task, 0, sizeof(*task));
+	init_timer(&task->tk_timer);
+	task->tk_timer.data     = (unsigned long) task;
+	task->tk_timer.function = (void (*)(unsigned long)) rpc_run_timer;
+	task->tk_client = clnt;
+	task->tk_flags  = flags;
+	task->tk_exit   = callback;
+
+	/* Initialize retry counters */
+	task->tk_garb_retry = 2;
+	task->tk_cred_retry = 2;
+
+	task->tk_priority = RPC_PRIORITY_NORMAL;
+	task->tk_cookie = (unsigned long)current;
+
+	/* Initialize workqueue for async tasks */
+	task->tk_workqueue = rpciod_workqueue;
+	if (!RPC_IS_ASYNC(task))
+		init_waitqueue_head(&task->u.tk_wait.waitq);
+
+	if (clnt) {
+		atomic_inc(&clnt->cl_users);
+		if (clnt->cl_softrtry)
+			task->tk_flags |= RPC_TASK_SOFT;
+		if (!clnt->cl_intr)
+			task->tk_flags |= RPC_TASK_NOINTR;
+	}
+
+#ifdef RPC_DEBUG
+	task->tk_magic = RPC_TASK_MAGIC_ID;
+	task->tk_pid = rpc_task_id++;
+#endif
+	/* Add to global list of all tasks */
+	spin_lock(&rpc_sched_lock);
+	list_add_tail(&task->tk_task, &all_tasks);
+	spin_unlock(&rpc_sched_lock);
+
+	dprintk("RPC: %4d new task procpid %d\n", task->tk_pid,
+				current->pid);
+}
+
+static struct rpc_task *
+rpc_alloc_task(void)
+{
+	return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOFS);
+}
+
+static void
+rpc_default_free_task(struct rpc_task *task)
+{
+	dprintk("RPC: %4d freeing task\n", task->tk_pid);
+	mempool_free(task, rpc_task_mempool);
+}
+
+/*
+ * Create a new task for the specified client.  We have to
+ * clean up after an allocation failure, as the client may
+ * have specified "oneshot".
+ */
+struct rpc_task *
+rpc_new_task(struct rpc_clnt *clnt, rpc_action callback, int flags)
+{
+	struct rpc_task	*task;
+
+	task = rpc_alloc_task();
+	if (!task)
+		goto cleanup;
+
+	rpc_init_task(task, clnt, callback, flags);
+
+	/* Replace tk_release */
+	task->tk_release = rpc_default_free_task;
+
+	dprintk("RPC: %4d allocated task\n", task->tk_pid);
+	task->tk_flags |= RPC_TASK_DYNAMIC;
+out:
+	return task;
+
+cleanup:
+	/* Check whether to release the client */
+	if (clnt) {
+		printk("rpc_new_task: failed, users=%d, oneshot=%d\n",
+			atomic_read(&clnt->cl_users), clnt->cl_oneshot);
+		atomic_inc(&clnt->cl_users); /* pretend we were used ... */
+		rpc_release_client(clnt);
+	}
+	goto out;
+}
+
+void rpc_release_task(struct rpc_task *task)
+{
+	dprintk("RPC: %4d release task\n", task->tk_pid);
+
+#ifdef RPC_DEBUG
+	BUG_ON(task->tk_magic != RPC_TASK_MAGIC_ID);
+#endif
+
+	/* Remove from global task list */
+	spin_lock(&rpc_sched_lock);
+	list_del(&task->tk_task);
+	spin_unlock(&rpc_sched_lock);
+
+	BUG_ON (RPC_IS_QUEUED(task));
+	task->tk_active = 0;
+
+	/* Synchronously delete any running timer */
+	rpc_delete_timer(task);
+
+	/* Release resources */
+	if (task->tk_rqstp)
+		xprt_release(task);
+	if (task->tk_msg.rpc_cred)
+		rpcauth_unbindcred(task);
+	rpc_free(task);
+	if (task->tk_client) {
+		rpc_release_client(task->tk_client);
+		task->tk_client = NULL;
+	}
+
+#ifdef RPC_DEBUG
+	task->tk_magic = 0;
+#endif
+	if (task->tk_release)
+		task->tk_release(task);
+}
+
+/**
+ * rpc_find_parent - find the parent of a child task.
+ * @child: child task
+ *
+ * Checks that the parent task is still sleeping on the
+ * queue 'childq'. If so returns a pointer to the parent.
+ * Upon failure returns NULL.
+ *
+ * Caller must hold childq.lock
+ */
+static inline struct rpc_task *rpc_find_parent(struct rpc_task *child)
+{
+	struct rpc_task	*task, *parent;
+	struct list_head *le;
+
+	parent = (struct rpc_task *) child->tk_calldata;
+	task_for_each(task, le, &childq.tasks[0])
+		if (task == parent)
+			return parent;
+
+	return NULL;
+}
+
+static void rpc_child_exit(struct rpc_task *child)
+{
+	struct rpc_task	*parent;
+
+	spin_lock_bh(&childq.lock);
+	if ((parent = rpc_find_parent(child)) != NULL) {
+		parent->tk_status = child->tk_status;
+		__rpc_wake_up_task(parent);
+	}
+	spin_unlock_bh(&childq.lock);
+}
+
+/*
+ * Note: rpc_new_task releases the client after a failure.
+ */
+struct rpc_task *
+rpc_new_child(struct rpc_clnt *clnt, struct rpc_task *parent)
+{
+	struct rpc_task	*task;
+
+	task = rpc_new_task(clnt, NULL, RPC_TASK_ASYNC | RPC_TASK_CHILD);
+	if (!task)
+		goto fail;
+	task->tk_exit = rpc_child_exit;
+	task->tk_calldata = parent;
+	return task;
+
+fail:
+	parent->tk_status = -ENOMEM;
+	return NULL;
+}
+
+void rpc_run_child(struct rpc_task *task, struct rpc_task *child, rpc_action func)
+{
+	spin_lock_bh(&childq.lock);
+	/* N.B. Is it possible for the child to have already finished? */
+	__rpc_sleep_on(&childq, task, func, NULL);
+	rpc_schedule_run(child);
+	spin_unlock_bh(&childq.lock);
+}
+
+/*
+ * Kill all tasks for the given client.
+ * XXX: kill their descendants as well?
+ */
+void rpc_killall_tasks(struct rpc_clnt *clnt)
+{
+	struct rpc_task	*rovr;
+	struct list_head *le;
+
+	dprintk("RPC:      killing all tasks for client %p\n", clnt);
+
+	/*
+	 * Spin lock all_tasks to prevent changes...
+	 */
+	spin_lock(&rpc_sched_lock);
+	alltask_for_each(rovr, le, &all_tasks) {
+		if (! RPC_IS_ACTIVATED(rovr))
+			continue;
+		if (!clnt || rovr->tk_client == clnt) {
+			rovr->tk_flags |= RPC_TASK_KILLED;
+			rpc_exit(rovr, -EIO);
+			rpc_wake_up_task(rovr);
+		}
+	}
+	spin_unlock(&rpc_sched_lock);
+}
+
+static DECLARE_MUTEX_LOCKED(rpciod_running);
+
+static void rpciod_killall(void)
+{
+	unsigned long flags;
+
+	while (!list_empty(&all_tasks)) {
+		clear_thread_flag(TIF_SIGPENDING);
+		rpc_killall_tasks(NULL);
+		flush_workqueue(rpciod_workqueue);
+		if (!list_empty(&all_tasks)) {
+			dprintk("rpciod_killall: waiting for tasks to exit\n");
+			yield();
+		}
+	}
+
+	spin_lock_irqsave(&current->sighand->siglock, flags);
+	recalc_sigpending();
+	spin_unlock_irqrestore(&current->sighand->siglock, flags);
+}
+
+/*
+ * Start up the rpciod process if it's not already running.
+ */
+int
+rpciod_up(void)
+{
+	struct workqueue_struct *wq;
+	int error = 0;
+
+	down(&rpciod_sema);
+	dprintk("rpciod_up: users %d\n", rpciod_users);
+	rpciod_users++;
+	if (rpciod_workqueue)
+		goto out;
+	/*
+	 * If there's no pid, we should be the first user.
+	 */
+	if (rpciod_users > 1)
+		printk(KERN_WARNING "rpciod_up: no workqueue, %d users??\n", rpciod_users);
+	/*
+	 * Create the rpciod thread and wait for it to start.
+	 */
+	error = -ENOMEM;
+	wq = create_workqueue("rpciod");
+	if (wq == NULL) {
+		printk(KERN_WARNING "rpciod_up: create workqueue failed, error=%d\n", error);
+		rpciod_users--;
+		goto out;
+	}
+	rpciod_workqueue = wq;
+	error = 0;
+out:
+	up(&rpciod_sema);
+	return error;
+}
+
+void
+rpciod_down(void)
+{
+	down(&rpciod_sema);
+	dprintk("rpciod_down sema %d\n", rpciod_users);
+	if (rpciod_users) {
+		if (--rpciod_users)
+			goto out;
+	} else
+		printk(KERN_WARNING "rpciod_down: no users??\n");
+
+	if (!rpciod_workqueue) {
+		dprintk("rpciod_down: Nothing to do!\n");
+		goto out;
+	}
+	rpciod_killall();
+
+	destroy_workqueue(rpciod_workqueue);
+	rpciod_workqueue = NULL;
+ out:
+	up(&rpciod_sema);
+}
+
+#ifdef RPC_DEBUG
+void rpc_show_tasks(void)
+{
+	struct list_head *le;
+	struct rpc_task *t;
+
+	spin_lock(&rpc_sched_lock);
+	if (list_empty(&all_tasks)) {
+		spin_unlock(&rpc_sched_lock);
+		return;
+	}
+	printk("-pid- proc flgs status -client- -prog- --rqstp- -timeout "
+		"-rpcwait -action- --exit--\n");
+	alltask_for_each(t, le, &all_tasks) {
+		const char *rpc_waitq = "none";
+
+		if (RPC_IS_QUEUED(t))
+			rpc_waitq = rpc_qname(t->u.tk_wait.rpc_waitq);
+
+		printk("%05d %04d %04x %06d %8p %6d %8p %08ld %8s %8p %8p\n",
+			t->tk_pid,
+			(t->tk_msg.rpc_proc ? t->tk_msg.rpc_proc->p_proc : -1),
+			t->tk_flags, t->tk_status,
+			t->tk_client,
+			(t->tk_client ? t->tk_client->cl_prog : 0),
+			t->tk_rqstp, t->tk_timeout,
+			rpc_waitq,
+			t->tk_action, t->tk_exit);
+	}
+	spin_unlock(&rpc_sched_lock);
+}
+#endif
+
+void
+rpc_destroy_mempool(void)
+{
+	if (rpc_buffer_mempool)
+		mempool_destroy(rpc_buffer_mempool);
+	if (rpc_task_mempool)
+		mempool_destroy(rpc_task_mempool);
+	if (rpc_task_slabp && kmem_cache_destroy(rpc_task_slabp))
+		printk(KERN_INFO "rpc_task: not all structures were freed\n");
+	if (rpc_buffer_slabp && kmem_cache_destroy(rpc_buffer_slabp))
+		printk(KERN_INFO "rpc_buffers: not all structures were freed\n");
+}
+
+int
+rpc_init_mempool(void)
+{
+	rpc_task_slabp = kmem_cache_create("rpc_tasks",
+					     sizeof(struct rpc_task),
+					     0, SLAB_HWCACHE_ALIGN,
+					     NULL, NULL);
+	if (!rpc_task_slabp)
+		goto err_nomem;
+	rpc_buffer_slabp = kmem_cache_create("rpc_buffers",
+					     RPC_BUFFER_MAXSIZE,
+					     0, SLAB_HWCACHE_ALIGN,
+					     NULL, NULL);
+	if (!rpc_buffer_slabp)
+		goto err_nomem;
+	rpc_task_mempool = mempool_create(RPC_TASK_POOLSIZE,
+					    mempool_alloc_slab,
+					    mempool_free_slab,
+					    rpc_task_slabp);
+	if (!rpc_task_mempool)
+		goto err_nomem;
+	rpc_buffer_mempool = mempool_create(RPC_BUFFER_POOLSIZE,
+					    mempool_alloc_slab,
+					    mempool_free_slab,
+					    rpc_buffer_slabp);
+	if (!rpc_buffer_mempool)
+		goto err_nomem;
+	return 0;
+err_nomem:
+	rpc_destroy_mempool();
+	return -ENOMEM;
+}