| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * 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/spinlock.h> |
| #include <linux/mutex.h> |
| #include <linux/freezer.h> |
| #include <linux/sched/mm.h> |
| |
| #include <linux/sunrpc/clnt.h> |
| #include <linux/sunrpc/metrics.h> |
| |
| #include "sunrpc.h" |
| |
| #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) |
| #define RPCDBG_FACILITY RPCDBG_SCHED |
| #endif |
| |
| #define CREATE_TRACE_POINTS |
| #include <trace/events/sunrpc.h> |
| |
| /* |
| * RPC slabs and memory pools |
| */ |
| #define RPC_BUFFER_MAXSIZE (2048) |
| #define RPC_BUFFER_POOLSIZE (8) |
| #define RPC_TASK_POOLSIZE (8) |
| static struct kmem_cache *rpc_task_slabp __read_mostly; |
| static struct kmem_cache *rpc_buffer_slabp __read_mostly; |
| static mempool_t *rpc_task_mempool __read_mostly; |
| static mempool_t *rpc_buffer_mempool __read_mostly; |
| |
| static void rpc_async_schedule(struct work_struct *); |
| static void rpc_release_task(struct rpc_task *task); |
| static void __rpc_queue_timer_fn(struct work_struct *); |
| |
| /* |
| * RPC tasks sit here while waiting for conditions to improve. |
| */ |
| static struct rpc_wait_queue delay_queue; |
| |
| /* |
| * rpciod-related stuff |
| */ |
| struct workqueue_struct *rpciod_workqueue __read_mostly; |
| struct workqueue_struct *xprtiod_workqueue __read_mostly; |
| EXPORT_SYMBOL_GPL(xprtiod_workqueue); |
| |
| unsigned long |
| rpc_task_timeout(const struct rpc_task *task) |
| { |
| unsigned long timeout = READ_ONCE(task->tk_timeout); |
| |
| if (timeout != 0) { |
| unsigned long now = jiffies; |
| if (time_before(now, timeout)) |
| return timeout - now; |
| } |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(rpc_task_timeout); |
| |
| /* |
| * 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 void |
| __rpc_disable_timer(struct rpc_wait_queue *queue, struct rpc_task *task) |
| { |
| if (list_empty(&task->u.tk_wait.timer_list)) |
| return; |
| dprintk("RPC: %5u disabling timer\n", task->tk_pid); |
| task->tk_timeout = 0; |
| list_del(&task->u.tk_wait.timer_list); |
| if (list_empty(&queue->timer_list.list)) |
| cancel_delayed_work(&queue->timer_list.dwork); |
| } |
| |
| static void |
| rpc_set_queue_timer(struct rpc_wait_queue *queue, unsigned long expires) |
| { |
| unsigned long now = jiffies; |
| queue->timer_list.expires = expires; |
| if (time_before_eq(expires, now)) |
| expires = 0; |
| else |
| expires -= now; |
| mod_delayed_work(rpciod_workqueue, &queue->timer_list.dwork, expires); |
| } |
| |
| /* |
| * Set up a timer for the current task. |
| */ |
| static void |
| __rpc_add_timer(struct rpc_wait_queue *queue, struct rpc_task *task, |
| unsigned long timeout) |
| { |
| dprintk("RPC: %5u setting alarm for %u ms\n", |
| task->tk_pid, jiffies_to_msecs(timeout - jiffies)); |
| |
| task->tk_timeout = timeout; |
| if (list_empty(&queue->timer_list.list) || time_before(timeout, queue->timer_list.expires)) |
| rpc_set_queue_timer(queue, timeout); |
| list_add(&task->u.tk_wait.timer_list, &queue->timer_list.list); |
| } |
| |
| static void rpc_set_waitqueue_priority(struct rpc_wait_queue *queue, int priority) |
| { |
| if (queue->priority != priority) { |
| queue->priority = priority; |
| queue->nr = 1U << priority; |
| } |
| } |
| |
| static void rpc_reset_waitqueue_priority(struct rpc_wait_queue *queue) |
| { |
| rpc_set_waitqueue_priority(queue, queue->maxpriority); |
| } |
| |
| /* |
| * Add a request to a queue list |
| */ |
| static void |
| __rpc_list_enqueue_task(struct list_head *q, struct rpc_task *task) |
| { |
| struct rpc_task *t; |
| |
| list_for_each_entry(t, q, u.tk_wait.list) { |
| if (t->tk_owner == task->tk_owner) { |
| list_add_tail(&task->u.tk_wait.links, |
| &t->u.tk_wait.links); |
| /* Cache the queue head in task->u.tk_wait.list */ |
| task->u.tk_wait.list.next = q; |
| task->u.tk_wait.list.prev = NULL; |
| return; |
| } |
| } |
| INIT_LIST_HEAD(&task->u.tk_wait.links); |
| list_add_tail(&task->u.tk_wait.list, q); |
| } |
| |
| /* |
| * Remove request from a queue list |
| */ |
| static void |
| __rpc_list_dequeue_task(struct rpc_task *task) |
| { |
| struct list_head *q; |
| struct rpc_task *t; |
| |
| if (task->u.tk_wait.list.prev == NULL) { |
| list_del(&task->u.tk_wait.links); |
| return; |
| } |
| if (!list_empty(&task->u.tk_wait.links)) { |
| t = list_first_entry(&task->u.tk_wait.links, |
| struct rpc_task, |
| u.tk_wait.links); |
| /* Assume __rpc_list_enqueue_task() cached the queue head */ |
| q = t->u.tk_wait.list.next; |
| list_add_tail(&t->u.tk_wait.list, q); |
| list_del(&task->u.tk_wait.links); |
| } |
| list_del(&task->u.tk_wait.list); |
| } |
| |
| /* |
| * Add new request to a priority queue. |
| */ |
| static void __rpc_add_wait_queue_priority(struct rpc_wait_queue *queue, |
| struct rpc_task *task, |
| unsigned char queue_priority) |
| { |
| if (unlikely(queue_priority > queue->maxpriority)) |
| queue_priority = queue->maxpriority; |
| __rpc_list_enqueue_task(&queue->tasks[queue_priority], task); |
| } |
| |
| /* |
| * 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, |
| unsigned char queue_priority) |
| { |
| WARN_ON_ONCE(RPC_IS_QUEUED(task)); |
| if (RPC_IS_QUEUED(task)) |
| return; |
| |
| INIT_LIST_HEAD(&task->u.tk_wait.timer_list); |
| if (RPC_IS_PRIORITY(queue)) |
| __rpc_add_wait_queue_priority(queue, task, queue_priority); |
| 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->tk_waitqueue = queue; |
| queue->qlen++; |
| /* barrier matches the read in rpc_wake_up_task_queue_locked() */ |
| smp_wmb(); |
| rpc_set_queued(task); |
| |
| dprintk("RPC: %5u 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) |
| { |
| __rpc_list_dequeue_task(task); |
| } |
| |
| /* |
| * Remove request from queue. |
| * Note: must be called with spin lock held. |
| */ |
| static void __rpc_remove_wait_queue(struct rpc_wait_queue *queue, struct rpc_task *task) |
| { |
| __rpc_disable_timer(queue, task); |
| if (RPC_IS_PRIORITY(queue)) |
| __rpc_remove_wait_queue_priority(task); |
| else |
| list_del(&task->u.tk_wait.list); |
| queue->qlen--; |
| dprintk("RPC: %5u removed from queue %p \"%s\"\n", |
| task->tk_pid, queue, rpc_qname(queue)); |
| } |
| |
| static void __rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname, unsigned char nr_queues) |
| { |
| int i; |
| |
| spin_lock_init(&queue->lock); |
| for (i = 0; i < ARRAY_SIZE(queue->tasks); i++) |
| INIT_LIST_HEAD(&queue->tasks[i]); |
| queue->maxpriority = nr_queues - 1; |
| rpc_reset_waitqueue_priority(queue); |
| queue->qlen = 0; |
| queue->timer_list.expires = 0; |
| INIT_DELAYED_WORK(&queue->timer_list.dwork, __rpc_queue_timer_fn); |
| INIT_LIST_HEAD(&queue->timer_list.list); |
| rpc_assign_waitqueue_name(queue, qname); |
| } |
| |
| void rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname) |
| { |
| __rpc_init_priority_wait_queue(queue, qname, RPC_NR_PRIORITY); |
| } |
| EXPORT_SYMBOL_GPL(rpc_init_priority_wait_queue); |
| |
| void rpc_init_wait_queue(struct rpc_wait_queue *queue, const char *qname) |
| { |
| __rpc_init_priority_wait_queue(queue, qname, 1); |
| } |
| EXPORT_SYMBOL_GPL(rpc_init_wait_queue); |
| |
| void rpc_destroy_wait_queue(struct rpc_wait_queue *queue) |
| { |
| cancel_delayed_work_sync(&queue->timer_list.dwork); |
| } |
| EXPORT_SYMBOL_GPL(rpc_destroy_wait_queue); |
| |
| static int rpc_wait_bit_killable(struct wait_bit_key *key, int mode) |
| { |
| freezable_schedule_unsafe(); |
| if (signal_pending_state(mode, current)) |
| return -ERESTARTSYS; |
| return 0; |
| } |
| |
| #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) || IS_ENABLED(CONFIG_TRACEPOINTS) |
| static void rpc_task_set_debuginfo(struct rpc_task *task) |
| { |
| static atomic_t rpc_pid; |
| |
| task->tk_pid = atomic_inc_return(&rpc_pid); |
| } |
| #else |
| static inline void rpc_task_set_debuginfo(struct rpc_task *task) |
| { |
| } |
| #endif |
| |
| static void rpc_set_active(struct rpc_task *task) |
| { |
| rpc_task_set_debuginfo(task); |
| set_bit(RPC_TASK_ACTIVE, &task->tk_runstate); |
| trace_rpc_task_begin(task, NULL); |
| } |
| |
| /* |
| * Mark an RPC call as having completed by clearing the 'active' bit |
| * and then waking up all tasks that were sleeping. |
| */ |
| static int rpc_complete_task(struct rpc_task *task) |
| { |
| void *m = &task->tk_runstate; |
| wait_queue_head_t *wq = bit_waitqueue(m, RPC_TASK_ACTIVE); |
| struct wait_bit_key k = __WAIT_BIT_KEY_INITIALIZER(m, RPC_TASK_ACTIVE); |
| unsigned long flags; |
| int ret; |
| |
| trace_rpc_task_complete(task, NULL); |
| |
| spin_lock_irqsave(&wq->lock, flags); |
| clear_bit(RPC_TASK_ACTIVE, &task->tk_runstate); |
| ret = atomic_dec_and_test(&task->tk_count); |
| if (waitqueue_active(wq)) |
| __wake_up_locked_key(wq, TASK_NORMAL, &k); |
| spin_unlock_irqrestore(&wq->lock, flags); |
| return ret; |
| } |
| |
| /* |
| * Allow callers to wait for completion of an RPC call |
| * |
| * Note the use of out_of_line_wait_on_bit() rather than wait_on_bit() |
| * to enforce taking of the wq->lock and hence avoid races with |
| * rpc_complete_task(). |
| */ |
| int __rpc_wait_for_completion_task(struct rpc_task *task, wait_bit_action_f *action) |
| { |
| if (action == NULL) |
| action = rpc_wait_bit_killable; |
| return out_of_line_wait_on_bit(&task->tk_runstate, RPC_TASK_ACTIVE, |
| action, TASK_KILLABLE); |
| } |
| EXPORT_SYMBOL_GPL(__rpc_wait_for_completion_task); |
| |
| /* |
| * Make an RPC task runnable. |
| * |
| * Note: If the task is ASYNC, and is being made runnable after sitting on an |
| * rpc_wait_queue, this must be called with the queue spinlock held to protect |
| * the wait queue operation. |
| * Note the ordering of rpc_test_and_set_running() and rpc_clear_queued(), |
| * which is needed to ensure that __rpc_execute() doesn't loop (due to the |
| * lockless RPC_IS_QUEUED() test) before we've had a chance to test |
| * the RPC_TASK_RUNNING flag. |
| */ |
| static void rpc_make_runnable(struct workqueue_struct *wq, |
| struct rpc_task *task) |
| { |
| bool need_wakeup = !rpc_test_and_set_running(task); |
| |
| rpc_clear_queued(task); |
| if (!need_wakeup) |
| return; |
| if (RPC_IS_ASYNC(task)) { |
| INIT_WORK(&task->u.tk_work, rpc_async_schedule); |
| queue_work(wq, &task->u.tk_work); |
| } else |
| wake_up_bit(&task->tk_runstate, RPC_TASK_QUEUED); |
| } |
| |
| /* |
| * 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_priority(struct rpc_wait_queue *q, |
| struct rpc_task *task, |
| unsigned char queue_priority) |
| { |
| dprintk("RPC: %5u sleep_on(queue \"%s\" time %lu)\n", |
| task->tk_pid, rpc_qname(q), jiffies); |
| |
| trace_rpc_task_sleep(task, q); |
| |
| __rpc_add_wait_queue(q, task, queue_priority); |
| |
| } |
| |
| static void __rpc_sleep_on_priority_timeout(struct rpc_wait_queue *q, |
| struct rpc_task *task, unsigned long timeout, |
| unsigned char queue_priority) |
| { |
| if (time_is_after_jiffies(timeout)) { |
| __rpc_sleep_on_priority(q, task, queue_priority); |
| __rpc_add_timer(q, task, timeout); |
| } else |
| task->tk_status = -ETIMEDOUT; |
| } |
| |
| static void rpc_set_tk_callback(struct rpc_task *task, rpc_action action) |
| { |
| if (action && !WARN_ON_ONCE(task->tk_callback != NULL)) |
| task->tk_callback = action; |
| } |
| |
| static bool rpc_sleep_check_activated(struct rpc_task *task) |
| { |
| /* We shouldn't ever put an inactive task to sleep */ |
| if (WARN_ON_ONCE(!RPC_IS_ACTIVATED(task))) { |
| task->tk_status = -EIO; |
| rpc_put_task_async(task); |
| return false; |
| } |
| return true; |
| } |
| |
| void rpc_sleep_on_timeout(struct rpc_wait_queue *q, struct rpc_task *task, |
| rpc_action action, unsigned long timeout) |
| { |
| if (!rpc_sleep_check_activated(task)) |
| return; |
| |
| rpc_set_tk_callback(task, action); |
| |
| /* |
| * Protect the queue operations. |
| */ |
| spin_lock(&q->lock); |
| __rpc_sleep_on_priority_timeout(q, task, timeout, task->tk_priority); |
| spin_unlock(&q->lock); |
| } |
| EXPORT_SYMBOL_GPL(rpc_sleep_on_timeout); |
| |
| void rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task, |
| rpc_action action) |
| { |
| if (!rpc_sleep_check_activated(task)) |
| return; |
| |
| rpc_set_tk_callback(task, action); |
| |
| WARN_ON_ONCE(task->tk_timeout != 0); |
| /* |
| * Protect the queue operations. |
| */ |
| spin_lock(&q->lock); |
| __rpc_sleep_on_priority(q, task, task->tk_priority); |
| spin_unlock(&q->lock); |
| } |
| EXPORT_SYMBOL_GPL(rpc_sleep_on); |
| |
| void rpc_sleep_on_priority_timeout(struct rpc_wait_queue *q, |
| struct rpc_task *task, unsigned long timeout, int priority) |
| { |
| if (!rpc_sleep_check_activated(task)) |
| return; |
| |
| priority -= RPC_PRIORITY_LOW; |
| /* |
| * Protect the queue operations. |
| */ |
| spin_lock(&q->lock); |
| __rpc_sleep_on_priority_timeout(q, task, timeout, priority); |
| spin_unlock(&q->lock); |
| } |
| EXPORT_SYMBOL_GPL(rpc_sleep_on_priority_timeout); |
| |
| void rpc_sleep_on_priority(struct rpc_wait_queue *q, struct rpc_task *task, |
| int priority) |
| { |
| if (!rpc_sleep_check_activated(task)) |
| return; |
| |
| WARN_ON_ONCE(task->tk_timeout != 0); |
| priority -= RPC_PRIORITY_LOW; |
| /* |
| * Protect the queue operations. |
| */ |
| spin_lock(&q->lock); |
| __rpc_sleep_on_priority(q, task, priority); |
| spin_unlock(&q->lock); |
| } |
| EXPORT_SYMBOL_GPL(rpc_sleep_on_priority); |
| |
| /** |
| * __rpc_do_wake_up_task_on_wq - wake up a single rpc_task |
| * @wq: workqueue on which to run task |
| * @queue: wait queue |
| * @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_on_wq(struct workqueue_struct *wq, |
| struct rpc_wait_queue *queue, |
| struct rpc_task *task) |
| { |
| dprintk("RPC: %5u __rpc_wake_up_task (now %lu)\n", |
| task->tk_pid, jiffies); |
| |
| /* 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; |
| } |
| |
| trace_rpc_task_wakeup(task, queue); |
| |
| __rpc_remove_wait_queue(queue, task); |
| |
| rpc_make_runnable(wq, task); |
| |
| dprintk("RPC: __rpc_wake_up_task done\n"); |
| } |
| |
| /* |
| * Wake up a queued task while the queue lock is being held |
| */ |
| static struct rpc_task * |
| rpc_wake_up_task_on_wq_queue_action_locked(struct workqueue_struct *wq, |
| struct rpc_wait_queue *queue, struct rpc_task *task, |
| bool (*action)(struct rpc_task *, void *), void *data) |
| { |
| if (RPC_IS_QUEUED(task)) { |
| smp_rmb(); |
| if (task->tk_waitqueue == queue) { |
| if (action == NULL || action(task, data)) { |
| __rpc_do_wake_up_task_on_wq(wq, queue, task); |
| return task; |
| } |
| } |
| } |
| return NULL; |
| } |
| |
| /* |
| * Wake up a queued task while the queue lock is being held |
| */ |
| static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue *queue, |
| struct rpc_task *task) |
| { |
| rpc_wake_up_task_on_wq_queue_action_locked(rpciod_workqueue, queue, |
| task, NULL, NULL); |
| } |
| |
| /* |
| * Wake up a task on a specific queue |
| */ |
| void rpc_wake_up_queued_task(struct rpc_wait_queue *queue, struct rpc_task *task) |
| { |
| if (!RPC_IS_QUEUED(task)) |
| return; |
| spin_lock(&queue->lock); |
| rpc_wake_up_task_queue_locked(queue, task); |
| spin_unlock(&queue->lock); |
| } |
| EXPORT_SYMBOL_GPL(rpc_wake_up_queued_task); |
| |
| static bool rpc_task_action_set_status(struct rpc_task *task, void *status) |
| { |
| task->tk_status = *(int *)status; |
| return true; |
| } |
| |
| static void |
| rpc_wake_up_task_queue_set_status_locked(struct rpc_wait_queue *queue, |
| struct rpc_task *task, int status) |
| { |
| rpc_wake_up_task_on_wq_queue_action_locked(rpciod_workqueue, queue, |
| task, rpc_task_action_set_status, &status); |
| } |
| |
| /** |
| * rpc_wake_up_queued_task_set_status - wake up a task and set task->tk_status |
| * @queue: pointer to rpc_wait_queue |
| * @task: pointer to rpc_task |
| * @status: integer error value |
| * |
| * If @task is queued on @queue, then it is woken up, and @task->tk_status is |
| * set to the value of @status. |
| */ |
| void |
| rpc_wake_up_queued_task_set_status(struct rpc_wait_queue *queue, |
| struct rpc_task *task, int status) |
| { |
| if (!RPC_IS_QUEUED(task)) |
| return; |
| spin_lock(&queue->lock); |
| rpc_wake_up_task_queue_set_status_locked(queue, task, status); |
| spin_unlock(&queue->lock); |
| } |
| |
| /* |
| * Wake up the next task on a priority queue. |
| */ |
| static struct rpc_task *__rpc_find_next_queued_priority(struct rpc_wait_queue *queue) |
| { |
| struct list_head *q; |
| struct rpc_task *task; |
| |
| /* |
| * Service a batch of tasks from a single owner. |
| */ |
| q = &queue->tasks[queue->priority]; |
| if (!list_empty(q) && --queue->nr) { |
| task = list_first_entry(q, struct rpc_task, u.tk_wait.list); |
| goto out; |
| } |
| |
| /* |
| * 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_first_entry(q, 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])); |
| out: |
| return task; |
| } |
| |
| static struct rpc_task *__rpc_find_next_queued(struct rpc_wait_queue *queue) |
| { |
| if (RPC_IS_PRIORITY(queue)) |
| return __rpc_find_next_queued_priority(queue); |
| if (!list_empty(&queue->tasks[0])) |
| return list_first_entry(&queue->tasks[0], struct rpc_task, u.tk_wait.list); |
| return NULL; |
| } |
| |
| /* |
| * Wake up the first task on the wait queue. |
| */ |
| struct rpc_task *rpc_wake_up_first_on_wq(struct workqueue_struct *wq, |
| struct rpc_wait_queue *queue, |
| bool (*func)(struct rpc_task *, void *), void *data) |
| { |
| struct rpc_task *task = NULL; |
| |
| dprintk("RPC: wake_up_first(%p \"%s\")\n", |
| queue, rpc_qname(queue)); |
| spin_lock(&queue->lock); |
| task = __rpc_find_next_queued(queue); |
| if (task != NULL) |
| task = rpc_wake_up_task_on_wq_queue_action_locked(wq, queue, |
| task, func, data); |
| spin_unlock(&queue->lock); |
| |
| return task; |
| } |
| |
| /* |
| * Wake up the first task on the wait queue. |
| */ |
| struct rpc_task *rpc_wake_up_first(struct rpc_wait_queue *queue, |
| bool (*func)(struct rpc_task *, void *), void *data) |
| { |
| return rpc_wake_up_first_on_wq(rpciod_workqueue, queue, func, data); |
| } |
| EXPORT_SYMBOL_GPL(rpc_wake_up_first); |
| |
| static bool rpc_wake_up_next_func(struct rpc_task *task, void *data) |
| { |
| return true; |
| } |
| |
| /* |
| * Wake up the next task on the wait queue. |
| */ |
| struct rpc_task *rpc_wake_up_next(struct rpc_wait_queue *queue) |
| { |
| return rpc_wake_up_first(queue, rpc_wake_up_next_func, NULL); |
| } |
| EXPORT_SYMBOL_GPL(rpc_wake_up_next); |
| |
| /** |
| * 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 list_head *head; |
| |
| spin_lock(&queue->lock); |
| head = &queue->tasks[queue->maxpriority]; |
| for (;;) { |
| while (!list_empty(head)) { |
| struct rpc_task *task; |
| task = list_first_entry(head, |
| struct rpc_task, |
| u.tk_wait.list); |
| rpc_wake_up_task_queue_locked(queue, task); |
| } |
| if (head == &queue->tasks[0]) |
| break; |
| head--; |
| } |
| spin_unlock(&queue->lock); |
| } |
| EXPORT_SYMBOL_GPL(rpc_wake_up); |
| |
| /** |
| * 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; |
| |
| spin_lock(&queue->lock); |
| head = &queue->tasks[queue->maxpriority]; |
| for (;;) { |
| while (!list_empty(head)) { |
| struct rpc_task *task; |
| task = list_first_entry(head, |
| struct rpc_task, |
| u.tk_wait.list); |
| task->tk_status = status; |
| rpc_wake_up_task_queue_locked(queue, task); |
| } |
| if (head == &queue->tasks[0]) |
| break; |
| head--; |
| } |
| spin_unlock(&queue->lock); |
| } |
| EXPORT_SYMBOL_GPL(rpc_wake_up_status); |
| |
| static void __rpc_queue_timer_fn(struct work_struct *work) |
| { |
| struct rpc_wait_queue *queue = container_of(work, |
| struct rpc_wait_queue, |
| timer_list.dwork.work); |
| struct rpc_task *task, *n; |
| unsigned long expires, now, timeo; |
| |
| spin_lock(&queue->lock); |
| expires = now = jiffies; |
| list_for_each_entry_safe(task, n, &queue->timer_list.list, u.tk_wait.timer_list) { |
| timeo = task->tk_timeout; |
| if (time_after_eq(now, timeo)) { |
| dprintk("RPC: %5u timeout\n", task->tk_pid); |
| task->tk_status = -ETIMEDOUT; |
| rpc_wake_up_task_queue_locked(queue, task); |
| continue; |
| } |
| if (expires == now || time_after(expires, timeo)) |
| expires = timeo; |
| } |
| if (!list_empty(&queue->timer_list.list)) |
| rpc_set_queue_timer(queue, expires); |
| spin_unlock(&queue->lock); |
| } |
| |
| static void __rpc_atrun(struct rpc_task *task) |
| { |
| if (task->tk_status == -ETIMEDOUT) |
| task->tk_status = 0; |
| } |
| |
| /* |
| * Run a task at a later time |
| */ |
| void rpc_delay(struct rpc_task *task, unsigned long delay) |
| { |
| rpc_sleep_on_timeout(&delay_queue, task, __rpc_atrun, jiffies + delay); |
| } |
| EXPORT_SYMBOL_GPL(rpc_delay); |
| |
| /* |
| * Helper to call task->tk_ops->rpc_call_prepare |
| */ |
| void rpc_prepare_task(struct rpc_task *task) |
| { |
| task->tk_ops->rpc_call_prepare(task, task->tk_calldata); |
| } |
| |
| static void |
| rpc_init_task_statistics(struct rpc_task *task) |
| { |
| /* Initialize retry counters */ |
| task->tk_garb_retry = 2; |
| task->tk_cred_retry = 2; |
| task->tk_rebind_retry = 2; |
| |
| /* starting timestamp */ |
| task->tk_start = ktime_get(); |
| } |
| |
| static void |
| rpc_reset_task_statistics(struct rpc_task *task) |
| { |
| task->tk_timeouts = 0; |
| task->tk_flags &= ~(RPC_CALL_MAJORSEEN|RPC_TASK_SENT); |
| rpc_init_task_statistics(task); |
| } |
| |
| /* |
| * Helper that calls task->tk_ops->rpc_call_done if it exists |
| */ |
| void rpc_exit_task(struct rpc_task *task) |
| { |
| trace_rpc_task_end(task, task->tk_action); |
| task->tk_action = NULL; |
| if (task->tk_ops->rpc_count_stats) |
| task->tk_ops->rpc_count_stats(task, task->tk_calldata); |
| else if (task->tk_client) |
| rpc_count_iostats(task, task->tk_client->cl_metrics); |
| if (task->tk_ops->rpc_call_done != NULL) { |
| task->tk_ops->rpc_call_done(task, task->tk_calldata); |
| if (task->tk_action != NULL) { |
| /* Always release the RPC slot and buffer memory */ |
| xprt_release(task); |
| rpc_reset_task_statistics(task); |
| } |
| } |
| } |
| |
| void rpc_signal_task(struct rpc_task *task) |
| { |
| struct rpc_wait_queue *queue; |
| |
| if (!RPC_IS_ACTIVATED(task)) |
| return; |
| |
| trace_rpc_task_signalled(task, task->tk_action); |
| set_bit(RPC_TASK_SIGNALLED, &task->tk_runstate); |
| smp_mb__after_atomic(); |
| queue = READ_ONCE(task->tk_waitqueue); |
| if (queue) |
| rpc_wake_up_queued_task_set_status(queue, task, -ERESTARTSYS); |
| } |
| |
| void rpc_exit(struct rpc_task *task, int status) |
| { |
| task->tk_status = status; |
| task->tk_action = rpc_exit_task; |
| rpc_wake_up_queued_task(task->tk_waitqueue, task); |
| } |
| EXPORT_SYMBOL_GPL(rpc_exit); |
| |
| void rpc_release_calldata(const struct rpc_call_ops *ops, void *calldata) |
| { |
| if (ops->rpc_release != NULL) |
| ops->rpc_release(calldata); |
| } |
| |
| /* |
| * This is the RPC `scheduler' (or rather, the finite state machine). |
| */ |
| static void __rpc_execute(struct rpc_task *task) |
| { |
| struct rpc_wait_queue *queue; |
| int task_is_async = RPC_IS_ASYNC(task); |
| int status = 0; |
| |
| dprintk("RPC: %5u __rpc_execute flags=0x%x\n", |
| task->tk_pid, task->tk_flags); |
| |
| WARN_ON_ONCE(RPC_IS_QUEUED(task)); |
| if (RPC_IS_QUEUED(task)) |
| return; |
| |
| for (;;) { |
| void (*do_action)(struct rpc_task *); |
| |
| /* |
| * Perform the next FSM step or a pending callback. |
| * |
| * tk_action may be NULL if the task has been killed. |
| * In particular, note that rpc_killall_tasks may |
| * do this at any time, so beware when dereferencing. |
| */ |
| do_action = task->tk_action; |
| if (task->tk_callback) { |
| do_action = task->tk_callback; |
| task->tk_callback = NULL; |
| } |
| if (!do_action) |
| break; |
| trace_rpc_task_run_action(task, do_action); |
| do_action(task); |
| |
| /* |
| * Lockless check for whether task is sleeping or not. |
| */ |
| if (!RPC_IS_QUEUED(task)) |
| continue; |
| |
| /* |
| * Signalled tasks should exit rather than sleep. |
| */ |
| if (RPC_SIGNALLED(task)) { |
| task->tk_rpc_status = -ERESTARTSYS; |
| rpc_exit(task, -ERESTARTSYS); |
| } |
| |
| /* |
| * The queue->lock protects against races with |
| * rpc_make_runnable(). |
| * |
| * Note that once we clear RPC_TASK_RUNNING on an asynchronous |
| * rpc_task, rpc_make_runnable() can assign it to a |
| * different workqueue. We therefore cannot assume that the |
| * rpc_task pointer may still be dereferenced. |
| */ |
| queue = task->tk_waitqueue; |
| spin_lock(&queue->lock); |
| if (!RPC_IS_QUEUED(task)) { |
| spin_unlock(&queue->lock); |
| continue; |
| } |
| rpc_clear_running(task); |
| spin_unlock(&queue->lock); |
| if (task_is_async) |
| return; |
| |
| /* sync task: sleep here */ |
| dprintk("RPC: %5u sync task going to sleep\n", task->tk_pid); |
| status = out_of_line_wait_on_bit(&task->tk_runstate, |
| RPC_TASK_QUEUED, rpc_wait_bit_killable, |
| TASK_KILLABLE); |
| if (status < 0) { |
| /* |
| * 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. |
| */ |
| trace_rpc_task_signalled(task, task->tk_action); |
| set_bit(RPC_TASK_SIGNALLED, &task->tk_runstate); |
| task->tk_rpc_status = -ERESTARTSYS; |
| rpc_exit(task, -ERESTARTSYS); |
| } |
| dprintk("RPC: %5u sync task resuming\n", task->tk_pid); |
| } |
| |
| dprintk("RPC: %5u return %d, status %d\n", task->tk_pid, status, |
| task->tk_status); |
| /* Release all resources associated with the task */ |
| rpc_release_task(task); |
| } |
| |
| /* |
| * 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. |
| */ |
| void rpc_execute(struct rpc_task *task) |
| { |
| bool is_async = RPC_IS_ASYNC(task); |
| |
| rpc_set_active(task); |
| rpc_make_runnable(rpciod_workqueue, task); |
| if (!is_async) |
| __rpc_execute(task); |
| } |
| |
| static void rpc_async_schedule(struct work_struct *work) |
| { |
| unsigned int pflags = memalloc_nofs_save(); |
| |
| __rpc_execute(container_of(work, struct rpc_task, u.tk_work)); |
| memalloc_nofs_restore(pflags); |
| } |
| |
| /** |
| * rpc_malloc - allocate RPC buffer resources |
| * @task: RPC task |
| * |
| * A single memory region is allocated, which is split between the |
| * RPC call and RPC reply that this task is being used for. When |
| * this RPC is retired, the memory is released by calling rpc_free. |
| * |
| * To prevent rpciod from hanging, this allocator never sleeps, |
| * returning -ENOMEM and suppressing warning if the request cannot |
| * be serviced immediately. The caller can arrange to sleep in a |
| * way that is safe for rpciod. |
| * |
| * Most requests are 'small' (under 2KiB) and can be serviced from a |
| * mempool, ensuring that NFS reads and writes can always proceed, |
| * and that there is good locality of reference for these buffers. |
| */ |
| int rpc_malloc(struct rpc_task *task) |
| { |
| struct rpc_rqst *rqst = task->tk_rqstp; |
| size_t size = rqst->rq_callsize + rqst->rq_rcvsize; |
| struct rpc_buffer *buf; |
| gfp_t gfp = GFP_NOFS; |
| |
| if (RPC_IS_SWAPPER(task)) |
| gfp = __GFP_MEMALLOC | GFP_NOWAIT | __GFP_NOWARN; |
| |
| size += sizeof(struct rpc_buffer); |
| if (size <= RPC_BUFFER_MAXSIZE) |
| buf = mempool_alloc(rpc_buffer_mempool, gfp); |
| else |
| buf = kmalloc(size, gfp); |
| |
| if (!buf) |
| return -ENOMEM; |
| |
| buf->len = size; |
| dprintk("RPC: %5u allocated buffer of size %zu at %p\n", |
| task->tk_pid, size, buf); |
| rqst->rq_buffer = buf->data; |
| rqst->rq_rbuffer = (char *)rqst->rq_buffer + rqst->rq_callsize; |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(rpc_malloc); |
| |
| /** |
| * rpc_free - free RPC buffer resources allocated via rpc_malloc |
| * @task: RPC task |
| * |
| */ |
| void rpc_free(struct rpc_task *task) |
| { |
| void *buffer = task->tk_rqstp->rq_buffer; |
| size_t size; |
| struct rpc_buffer *buf; |
| |
| buf = container_of(buffer, struct rpc_buffer, data); |
| size = buf->len; |
| |
| dprintk("RPC: freeing buffer of size %zu at %p\n", |
| size, buf); |
| |
| if (size <= RPC_BUFFER_MAXSIZE) |
| mempool_free(buf, rpc_buffer_mempool); |
| else |
| kfree(buf); |
| } |
| EXPORT_SYMBOL_GPL(rpc_free); |
| |
| /* |
| * Creation and deletion of RPC task structures |
| */ |
| static void rpc_init_task(struct rpc_task *task, const struct rpc_task_setup *task_setup_data) |
| { |
| memset(task, 0, sizeof(*task)); |
| atomic_set(&task->tk_count, 1); |
| task->tk_flags = task_setup_data->flags; |
| task->tk_ops = task_setup_data->callback_ops; |
| task->tk_calldata = task_setup_data->callback_data; |
| INIT_LIST_HEAD(&task->tk_task); |
| |
| task->tk_priority = task_setup_data->priority - RPC_PRIORITY_LOW; |
| task->tk_owner = current->tgid; |
| |
| /* Initialize workqueue for async tasks */ |
| task->tk_workqueue = task_setup_data->workqueue; |
| |
| task->tk_xprt = rpc_task_get_xprt(task_setup_data->rpc_client, |
| xprt_get(task_setup_data->rpc_xprt)); |
| |
| task->tk_op_cred = get_rpccred(task_setup_data->rpc_op_cred); |
| |
| if (task->tk_ops->rpc_call_prepare != NULL) |
| task->tk_action = rpc_prepare_task; |
| |
| rpc_init_task_statistics(task); |
| |
| dprintk("RPC: new task initialized, procpid %u\n", |
| task_pid_nr(current)); |
| } |
| |
| static struct rpc_task * |
| rpc_alloc_task(void) |
| { |
| return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOFS); |
| } |
| |
| /* |
| * Create a new task for the specified client. |
| */ |
| struct rpc_task *rpc_new_task(const struct rpc_task_setup *setup_data) |
| { |
| struct rpc_task *task = setup_data->task; |
| unsigned short flags = 0; |
| |
| if (task == NULL) { |
| task = rpc_alloc_task(); |
| flags = RPC_TASK_DYNAMIC; |
| } |
| |
| rpc_init_task(task, setup_data); |
| task->tk_flags |= flags; |
| dprintk("RPC: allocated task %p\n", task); |
| return task; |
| } |
| |
| /* |
| * rpc_free_task - release rpc task and perform cleanups |
| * |
| * Note that we free up the rpc_task _after_ rpc_release_calldata() |
| * in order to work around a workqueue dependency issue. |
| * |
| * Tejun Heo states: |
| * "Workqueue currently considers two work items to be the same if they're |
| * on the same address and won't execute them concurrently - ie. it |
| * makes a work item which is queued again while being executed wait |
| * for the previous execution to complete. |
| * |
| * If a work function frees the work item, and then waits for an event |
| * which should be performed by another work item and *that* work item |
| * recycles the freed work item, it can create a false dependency loop. |
| * There really is no reliable way to detect this short of verifying |
| * every memory free." |
| * |
| */ |
| static void rpc_free_task(struct rpc_task *task) |
| { |
| unsigned short tk_flags = task->tk_flags; |
| |
| put_rpccred(task->tk_op_cred); |
| rpc_release_calldata(task->tk_ops, task->tk_calldata); |
| |
| if (tk_flags & RPC_TASK_DYNAMIC) { |
| dprintk("RPC: %5u freeing task\n", task->tk_pid); |
| mempool_free(task, rpc_task_mempool); |
| } |
| } |
| |
| static void rpc_async_release(struct work_struct *work) |
| { |
| unsigned int pflags = memalloc_nofs_save(); |
| |
| rpc_free_task(container_of(work, struct rpc_task, u.tk_work)); |
| memalloc_nofs_restore(pflags); |
| } |
| |
| static void rpc_release_resources_task(struct rpc_task *task) |
| { |
| xprt_release(task); |
| if (task->tk_msg.rpc_cred) { |
| put_cred(task->tk_msg.rpc_cred); |
| task->tk_msg.rpc_cred = NULL; |
| } |
| rpc_task_release_client(task); |
| } |
| |
| static void rpc_final_put_task(struct rpc_task *task, |
| struct workqueue_struct *q) |
| { |
| if (q != NULL) { |
| INIT_WORK(&task->u.tk_work, rpc_async_release); |
| queue_work(q, &task->u.tk_work); |
| } else |
| rpc_free_task(task); |
| } |
| |
| static void rpc_do_put_task(struct rpc_task *task, struct workqueue_struct *q) |
| { |
| if (atomic_dec_and_test(&task->tk_count)) { |
| rpc_release_resources_task(task); |
| rpc_final_put_task(task, q); |
| } |
| } |
| |
| void rpc_put_task(struct rpc_task *task) |
| { |
| rpc_do_put_task(task, NULL); |
| } |
| EXPORT_SYMBOL_GPL(rpc_put_task); |
| |
| void rpc_put_task_async(struct rpc_task *task) |
| { |
| rpc_do_put_task(task, task->tk_workqueue); |
| } |
| EXPORT_SYMBOL_GPL(rpc_put_task_async); |
| |
| static void rpc_release_task(struct rpc_task *task) |
| { |
| dprintk("RPC: %5u release task\n", task->tk_pid); |
| |
| WARN_ON_ONCE(RPC_IS_QUEUED(task)); |
| |
| rpc_release_resources_task(task); |
| |
| /* |
| * Note: at this point we have been removed from rpc_clnt->cl_tasks, |
| * so it should be safe to use task->tk_count as a test for whether |
| * or not any other processes still hold references to our rpc_task. |
| */ |
| if (atomic_read(&task->tk_count) != 1 + !RPC_IS_ASYNC(task)) { |
| /* Wake up anyone who may be waiting for task completion */ |
| if (!rpc_complete_task(task)) |
| return; |
| } else { |
| if (!atomic_dec_and_test(&task->tk_count)) |
| return; |
| } |
| rpc_final_put_task(task, task->tk_workqueue); |
| } |
| |
| int rpciod_up(void) |
| { |
| return try_module_get(THIS_MODULE) ? 0 : -EINVAL; |
| } |
| |
| void rpciod_down(void) |
| { |
| module_put(THIS_MODULE); |
| } |
| |
| /* |
| * Start up the rpciod workqueue. |
| */ |
| static int rpciod_start(void) |
| { |
| struct workqueue_struct *wq; |
| |
| /* |
| * Create the rpciod thread and wait for it to start. |
| */ |
| dprintk("RPC: creating workqueue rpciod\n"); |
| wq = alloc_workqueue("rpciod", WQ_MEM_RECLAIM | WQ_UNBOUND, 0); |
| if (!wq) |
| goto out_failed; |
| rpciod_workqueue = wq; |
| /* Note: highpri because network receive is latency sensitive */ |
| wq = alloc_workqueue("xprtiod", WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_HIGHPRI, 0); |
| if (!wq) |
| goto free_rpciod; |
| xprtiod_workqueue = wq; |
| return 1; |
| free_rpciod: |
| wq = rpciod_workqueue; |
| rpciod_workqueue = NULL; |
| destroy_workqueue(wq); |
| out_failed: |
| return 0; |
| } |
| |
| static void rpciod_stop(void) |
| { |
| struct workqueue_struct *wq = NULL; |
| |
| if (rpciod_workqueue == NULL) |
| return; |
| dprintk("RPC: destroying workqueue rpciod\n"); |
| |
| wq = rpciod_workqueue; |
| rpciod_workqueue = NULL; |
| destroy_workqueue(wq); |
| wq = xprtiod_workqueue; |
| xprtiod_workqueue = NULL; |
| destroy_workqueue(wq); |
| } |
| |
| void |
| rpc_destroy_mempool(void) |
| { |
| rpciod_stop(); |
| mempool_destroy(rpc_buffer_mempool); |
| mempool_destroy(rpc_task_mempool); |
| kmem_cache_destroy(rpc_task_slabp); |
| kmem_cache_destroy(rpc_buffer_slabp); |
| rpc_destroy_wait_queue(&delay_queue); |
| } |
| |
| int |
| rpc_init_mempool(void) |
| { |
| /* |
| * The following is not strictly a mempool initialisation, |
| * but there is no harm in doing it here |
| */ |
| rpc_init_wait_queue(&delay_queue, "delayq"); |
| if (!rpciod_start()) |
| goto err_nomem; |
| |
| rpc_task_slabp = kmem_cache_create("rpc_tasks", |
| sizeof(struct rpc_task), |
| 0, SLAB_HWCACHE_ALIGN, |
| NULL); |
| if (!rpc_task_slabp) |
| goto err_nomem; |
| rpc_buffer_slabp = kmem_cache_create("rpc_buffers", |
| RPC_BUFFER_MAXSIZE, |
| 0, SLAB_HWCACHE_ALIGN, |
| NULL); |
| if (!rpc_buffer_slabp) |
| goto err_nomem; |
| rpc_task_mempool = mempool_create_slab_pool(RPC_TASK_POOLSIZE, |
| rpc_task_slabp); |
| if (!rpc_task_mempool) |
| goto err_nomem; |
| rpc_buffer_mempool = mempool_create_slab_pool(RPC_BUFFER_POOLSIZE, |
| rpc_buffer_slabp); |
| if (!rpc_buffer_mempool) |
| goto err_nomem; |
| return 0; |
| err_nomem: |
| rpc_destroy_mempool(); |
| return -ENOMEM; |
| } |