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/*
* Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
* Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* OpenIB.org BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/hardirq.h>
#include "rxe_task.h"
int __rxe_do_task(struct rxe_task *task)
{
int ret;
while ((ret = task->func(task->arg)) == 0)
;
task->ret = ret;
return ret;
}
/*
* this locking is due to a potential race where
* a second caller finds the task already running
* but looks just after the last call to func
*/
void rxe_do_task(unsigned long data)
{
int cont;
int ret;
unsigned long flags;
struct rxe_task *task = (struct rxe_task *)data;
spin_lock_irqsave(&task->state_lock, flags);
switch (task->state) {
case TASK_STATE_START:
task->state = TASK_STATE_BUSY;
spin_unlock_irqrestore(&task->state_lock, flags);
break;
case TASK_STATE_BUSY:
task->state = TASK_STATE_ARMED;
/* fall through */
case TASK_STATE_ARMED:
spin_unlock_irqrestore(&task->state_lock, flags);
return;
default:
spin_unlock_irqrestore(&task->state_lock, flags);
pr_warn("%s failed with bad state %d\n", __func__, task->state);
return;
}
do {
cont = 0;
ret = task->func(task->arg);
spin_lock_irqsave(&task->state_lock, flags);
switch (task->state) {
case TASK_STATE_BUSY:
if (ret)
task->state = TASK_STATE_START;
else
cont = 1;
break;
/* soneone tried to run the task since the last time we called
* func, so we will call one more time regardless of the
* return value
*/
case TASK_STATE_ARMED:
task->state = TASK_STATE_BUSY;
cont = 1;
break;
default:
pr_warn("%s failed with bad state %d\n", __func__,
task->state);
}
spin_unlock_irqrestore(&task->state_lock, flags);
} while (cont);
task->ret = ret;
}
int rxe_init_task(struct rxe_task *task, void *arg, int (*func)(void *))
{
task->arg = arg;
task->func = func;
task->destroyed = false;
tasklet_init(&task->tasklet, rxe_do_task, (unsigned long)task);
task->state = TASK_STATE_START;
spin_lock_init(&task->state_lock);
return 0;
}
void rxe_cleanup_task(struct rxe_task *task)
{
unsigned long flags;
bool idle;
/*
* Mark the task, then wait for it to finish. It might be
* running in a non-tasklet (direct call) context.
*/
task->destroyed = true;
do {
spin_lock_irqsave(&task->state_lock, flags);
idle = (task->state == TASK_STATE_START);
spin_unlock_irqrestore(&task->state_lock, flags);
} while (!idle);
tasklet_kill(&task->tasklet);
}
void rxe_run_task(struct rxe_task *task, int sched)
{
if (task->destroyed)
return;
if (sched)
tasklet_schedule(&task->tasklet);
else
rxe_do_task((unsigned long)task);
}
void rxe_disable_task(struct rxe_task *task)
{
tasklet_disable(&task->tasklet);
}
void rxe_enable_task(struct rxe_task *task)
{
tasklet_enable(&task->tasklet);
}
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