sched.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_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);
}
}
}
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, return %d, status %d\n", task->tk_pid, 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);
}
/**
* rpc_malloc - allocate an RPC buffer
* @task: RPC task that will use this buffer
* @size: requested byte size
*
* 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)
{
struct rpc_rqst *req = task->tk_rqstp;
gfp_t gfp;
if (task->tk_flags & RPC_TASK_SWAPPER)
gfp = GFP_ATOMIC;
else
gfp = GFP_NOFS;
if (size > RPC_BUFFER_MAXSIZE) {
req->rq_buffer = kmalloc(size, gfp);
if (req->rq_buffer)
req->rq_bufsize = size;
} else {
req->rq_buffer = mempool_alloc(rpc_buffer_mempool, gfp);
if (req->rq_buffer)
req->rq_bufsize = RPC_BUFFER_MAXSIZE;
}
return req->rq_buffer;
}
/**
* rpc_free - free buffer allocated via rpc_malloc
* @task: RPC task with a buffer to be freed
*
*/
void rpc_free(struct rpc_task *task)
{
struct rpc_rqst *req = task->tk_rqstp;
if (req->rq_buffer) {
if (req->rq_bufsize == RPC_BUFFER_MAXSIZE)
mempool_free(req->rq_buffer, rpc_buffer_mempool);
else
kfree(req->rq_buffer);
req->rq_buffer = NULL;
req->rq_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);
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(¤t->sighand->siglock, flags);
recalc_sigpending();
spin_unlock_irqrestore(¤t->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;
}