/***
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*
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* stack/rtnet_rtpc.c
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*
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* RTnet - real-time networking subsystem
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*
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* Copyright (C) 2003-2005 Jan Kiszka <jan.kiszka@web.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/wait.h>
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#include <rtnet_rtpc.h>
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#include <rtdm/driver.h>
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static DEFINE_RTDM_LOCK(pending_calls_lock);
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static DEFINE_RTDM_LOCK(processed_calls_lock);
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static rtdm_event_t dispatch_event;
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static rtdm_task_t dispatch_task;
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static rtdm_nrtsig_t rtpc_nrt_signal;
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LIST_HEAD(pending_calls);
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LIST_HEAD(processed_calls);
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#ifndef __wait_event_interruptible_timeout
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#define __wait_event_interruptible_timeout(wq, condition, ret) \
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do { \
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wait_queue_t __wait; \
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init_waitqueue_entry(&__wait, current); \
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\
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add_wait_queue(&wq, &__wait); \
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for (;;) { \
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set_current_state(TASK_INTERRUPTIBLE); \
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if (condition) \
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break; \
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if (!signal_pending(current)) { \
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ret = schedule_timeout(ret); \
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if (!ret) \
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break; \
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continue; \
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} \
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ret = -ERESTARTSYS; \
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break; \
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} \
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current->state = TASK_RUNNING; \
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remove_wait_queue(&wq, &__wait); \
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} while (0)
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#endif
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#ifndef wait_event_interruptible_timeout
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#define wait_event_interruptible_timeout(wq, condition, timeout) \
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({ \
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long __ret = timeout; \
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if (!(condition)) \
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__wait_event_interruptible_timeout(wq, condition, \
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__ret); \
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__ret; \
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})
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#endif
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int rtnet_rtpc_dispatch_call(rtpc_proc proc, unsigned int timeout,
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void *priv_data, size_t priv_data_size,
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rtpc_copy_back_proc copy_back_handler,
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rtpc_cleanup_proc cleanup_handler)
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{
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struct rt_proc_call *call;
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rtdm_lockctx_t context;
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int ret;
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call = kmalloc(sizeof(struct rt_proc_call) + priv_data_size,
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GFP_KERNEL);
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if (call == NULL)
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return -ENOMEM;
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memcpy(call->priv_data, priv_data, priv_data_size);
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call->processed = 0;
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call->proc = proc;
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call->result = 0;
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call->cleanup_handler = cleanup_handler;
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atomic_set(&call->ref_count, 2); /* dispatcher + rt-procedure */
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init_waitqueue_head(&call->call_wq);
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rtdm_lock_get_irqsave(&pending_calls_lock, context);
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list_add_tail(&call->list_entry, &pending_calls);
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rtdm_lock_put_irqrestore(&pending_calls_lock, context);
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rtdm_event_signal(&dispatch_event);
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if (timeout > 0) {
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ret = wait_event_interruptible_timeout(
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call->call_wq, call->processed, (timeout * HZ) / 1000);
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if (ret == 0)
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ret = -ETIME;
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} else
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ret = wait_event_interruptible(call->call_wq, call->processed);
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if (ret >= 0) {
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if (copy_back_handler != NULL)
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copy_back_handler(call, priv_data);
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ret = call->result;
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}
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if (atomic_dec_and_test(&call->ref_count)) {
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if (call->cleanup_handler != NULL)
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call->cleanup_handler(&call->priv_data);
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kfree(call);
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}
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return ret;
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}
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static inline struct rt_proc_call *rtpc_dequeue_pending_call(void)
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{
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rtdm_lockctx_t context;
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struct rt_proc_call *call = NULL;
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rtdm_lock_get_irqsave(&pending_calls_lock, context);
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if (!list_empty(&pending_calls)) {
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call = (struct rt_proc_call *)pending_calls.next;
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list_del(&call->list_entry);
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}
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rtdm_lock_put_irqrestore(&pending_calls_lock, context);
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return call;
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}
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static inline void rtpc_queue_processed_call(struct rt_proc_call *call)
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{
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rtdm_lockctx_t context;
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bool trigger;
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rtdm_lock_get_irqsave(&processed_calls_lock, context);
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trigger = list_empty(&processed_calls);
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list_add_tail(&call->list_entry, &processed_calls);
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rtdm_lock_put_irqrestore(&processed_calls_lock, context);
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if (trigger)
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rtdm_nrtsig_pend(&rtpc_nrt_signal);
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}
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static inline struct rt_proc_call *rtpc_dequeue_processed_call(void)
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{
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rtdm_lockctx_t context;
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struct rt_proc_call *call = NULL;
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rtdm_lock_get_irqsave(&processed_calls_lock, context);
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if (!list_empty(&processed_calls)) {
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call = (struct rt_proc_call *)processed_calls.next;
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list_del(&call->list_entry);
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}
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rtdm_lock_put_irqrestore(&processed_calls_lock, context);
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return call;
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}
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static void rtpc_dispatch_handler(void *arg)
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{
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struct rt_proc_call *call;
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int ret;
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while (!rtdm_task_should_stop()) {
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if (rtdm_event_wait(&dispatch_event) < 0)
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break;
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while ((call = rtpc_dequeue_pending_call())) {
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ret = call->proc(call);
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if (ret != -CALL_PENDING)
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rtpc_complete_call(call, ret);
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}
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}
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}
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static void rtpc_signal_handler(rtdm_nrtsig_t *nrt_sig, void *arg)
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{
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struct rt_proc_call *call;
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while ((call = rtpc_dequeue_processed_call()) != NULL) {
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call->processed = 1;
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wake_up(&call->call_wq);
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if (atomic_dec_and_test(&call->ref_count)) {
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if (call->cleanup_handler != NULL)
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call->cleanup_handler(&call->priv_data);
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kfree(call);
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}
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}
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}
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void rtnet_rtpc_complete_call(struct rt_proc_call *call, int result)
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{
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call->result = result;
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rtpc_queue_processed_call(call);
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}
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void rtnet_rtpc_complete_call_nrt(struct rt_proc_call *call, int result)
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{
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RTNET_ASSERT(!rtdm_in_rt_context(),
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rtnet_rtpc_complete_call(call, result);
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return;);
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call->processed = 1;
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wake_up(&call->call_wq);
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if (atomic_dec_and_test(&call->ref_count)) {
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if (call->cleanup_handler != NULL)
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call->cleanup_handler(&call->priv_data);
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kfree(call);
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}
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}
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int __init rtpc_init(void)
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{
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int ret;
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rtdm_nrtsig_init(&rtpc_nrt_signal, rtpc_signal_handler, NULL);
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rtdm_event_init(&dispatch_event, 0);
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ret = rtdm_task_init(&dispatch_task, "rtnet-rtpc",
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rtpc_dispatch_handler, 0,
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RTDM_TASK_LOWEST_PRIORITY, 0);
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if (ret < 0) {
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rtdm_event_destroy(&dispatch_event);
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rtdm_nrtsig_destroy(&rtpc_nrt_signal);
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}
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return ret;
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}
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void rtpc_cleanup(void)
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{
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rtdm_event_destroy(&dispatch_event);
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rtdm_task_destroy(&dispatch_task);
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rtdm_nrtsig_destroy(&rtpc_nrt_signal);
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}
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EXPORT_SYMBOL_GPL(rtnet_rtpc_dispatch_call);
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EXPORT_SYMBOL_GPL(rtnet_rtpc_complete_call);
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EXPORT_SYMBOL_GPL(rtnet_rtpc_complete_call_nrt);
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