linux/net/sunrpc/sched.c
Trond Myklebust 44c288732f NFSv4: stateful NFSv4 RPC call interface
The NFSv4 model requires us to complete all RPC calls that might
 establish state on the server whether or not the user wants to
 interrupt it. We may also need to schedule new work (including
 new RPC calls) in order to cancel the new state.

 The asynchronous RPC model will allow us to ensure that RPC calls
 always complete, but in order to allow for "synchronous" RPC, we
 want to add the ability to wait for completion.
 The waits are, of course, interruptible.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-01-06 14:58:40 -05:00

1178 lines
28 KiB
C

/*
* 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 __read_mostly;
static kmem_cache_t *rpc_buffer_slabp __read_mostly;
static mempool_t *rpc_task_mempool __read_mostly;
static mempool_t *rpc_buffer_mempool __read_mostly;
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);
static int rpc_wait_bit_interruptible(void *word)
{
if (signal_pending(current))
return -ERESTARTSYS;
schedule();
return 0;
}
/*
* Mark an RPC call as having completed by clearing the 'active' bit
*/
static inline void rpc_mark_complete_task(struct rpc_task *task)
{
rpc_clear_active(task);
wake_up_bit(&task->tk_runstate, RPC_TASK_ACTIVE);
}
/*
* Allow callers to wait for completion of an RPC call
*/
int __rpc_wait_for_completion_task(struct rpc_task *task, int (*action)(void *))
{
if (action == NULL)
action = rpc_wait_bit_interruptible;
return wait_on_bit(&task->tk_runstate, RPC_TASK_ACTIVE,
action, TASK_INTERRUPTIBLE);
}
EXPORT_SYMBOL(__rpc_wait_for_completion_task);
/*
* 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_bit(&task->tk_runstate, RPC_TASK_QUEUED);
}
/*
* Place a newly initialized task on the workqueue.
*/
static inline void
rpc_schedule_run(struct rpc_task *task)
{
rpc_set_active(task);
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 */
rpc_set_active(task);
__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);
}
/*
* Helper to call task->tk_ops->rpc_call_prepare
*/
static void rpc_prepare_task(struct rpc_task *task)
{
task->tk_ops->rpc_call_prepare(task, task->tk_calldata);
}
/*
* Helper that calls task->tk_ops->rpc_call_done if it exists
*/
void rpc_exit_task(struct rpc_task *task)
{
task->tk_action = NULL;
if (task->tk_ops->rpc_call_done != NULL) {
task->tk_ops->rpc_call_done(task, task->tk_calldata);
if (task->tk_action != NULL) {
WARN_ON(RPC_ASSASSINATED(task));
/* Always release the RPC slot and buffer memory */
xprt_release(task);
rpc_free(task);
}
}
}
EXPORT_SYMBOL(rpc_exit_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));
for (;;) {
/*
* 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 == NULL)
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);
/* Note: Caller should be using rpc_clnt_sigmask() */
status = out_of_line_wait_on_bit(&task->tk_runstate,
RPC_TASK_QUEUED, rpc_wait_bit_interruptible,
TASK_INTERRUPTIBLE);
if (status == -ERESTARTSYS) {
/*
* 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.
*/
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);
}
dprintk("RPC: %4d exit() = %d\n", task->tk_pid, task->tk_status);
status = task->tk_status;
/* Wake up anyone who is waiting for task completion */
rpc_mark_complete_task(task);
/* 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)
{
rpc_set_active(task);
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)
{
gfp_t 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, int flags, const struct rpc_call_ops *tk_ops, void *calldata)
{
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;
atomic_set(&task->tk_count, 1);
task->tk_client = clnt;
task->tk_flags = flags;
task->tk_ops = tk_ops;
if (tk_ops->rpc_call_prepare != NULL)
task->tk_action = rpc_prepare_task;
task->tk_calldata = calldata;
/* 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 (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);
BUG_ON(task->tk_ops == NULL);
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_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, int flags, const struct rpc_call_ops *tk_ops, void *calldata)
{
struct rpc_task *task;
task = rpc_alloc_task();
if (!task)
goto cleanup;
rpc_init_task(task, clnt, flags, tk_ops, calldata);
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)
{
const struct rpc_call_ops *tk_ops = task->tk_ops;
void *calldata = task->tk_calldata;
#ifdef RPC_DEBUG
BUG_ON(task->tk_magic != RPC_TASK_MAGIC_ID);
#endif
if (!atomic_dec_and_test(&task->tk_count))
return;
dprintk("RPC: %4d release task\n", task->tk_pid);
/* 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));
/* 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_flags & RPC_TASK_DYNAMIC)
rpc_free_task(task);
if (tk_ops->rpc_release)
tk_ops->rpc_release(calldata);
}
/**
* rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
* @clnt - pointer to RPC client
* @flags - RPC flags
* @ops - RPC call ops
* @data - user call data
*/
struct rpc_task *rpc_run_task(struct rpc_clnt *clnt, int flags,
const struct rpc_call_ops *ops,
void *data)
{
struct rpc_task *task;
task = rpc_new_task(clnt, flags, ops, data);
if (task == NULL)
return ERR_PTR(-ENOMEM);
atomic_inc(&task->tk_count);
rpc_execute(task);
return task;
}
EXPORT_SYMBOL(rpc_run_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 *parent)
{
struct rpc_task *task;
struct list_head *le;
task_for_each(task, le, &childq.tasks[0])
if (task == parent)
return parent;
return NULL;
}
static void rpc_child_exit(struct rpc_task *child, void *calldata)
{
struct rpc_task *parent;
spin_lock_bh(&childq.lock);
if ((parent = rpc_find_parent(child, calldata)) != NULL) {
parent->tk_status = child->tk_status;
__rpc_wake_up_task(parent);
}
spin_unlock_bh(&childq.lock);
}
static const struct rpc_call_ops rpc_child_ops = {
.rpc_call_done = rpc_child_exit,
};
/*
* 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, RPC_TASK_ASYNC | RPC_TASK_CHILD, &rpc_child_ops, parent);
if (!task)
goto fail;
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- ---ops--\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_ops);
}
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;
}