155 lines
3.0 KiB
C
155 lines
3.0 KiB
C
// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
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/*
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* Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
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* Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
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*/
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#include <linux/kernel.h>
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#include <linux/interrupt.h>
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#include <linux/hardirq.h>
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#include "rxe.h"
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int __rxe_do_task(struct rxe_task *task)
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{
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int ret;
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while ((ret = task->func(task->arg)) == 0)
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;
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task->ret = ret;
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return ret;
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}
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/*
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* this locking is due to a potential race where
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* a second caller finds the task already running
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* but looks just after the last call to func
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*/
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void rxe_do_task(struct tasklet_struct *t)
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{
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int cont;
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int ret;
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struct rxe_task *task = from_tasklet(task, t, tasklet);
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unsigned int iterations = RXE_MAX_ITERATIONS;
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spin_lock_bh(&task->state_lock);
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switch (task->state) {
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case TASK_STATE_START:
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task->state = TASK_STATE_BUSY;
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spin_unlock_bh(&task->state_lock);
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break;
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case TASK_STATE_BUSY:
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task->state = TASK_STATE_ARMED;
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fallthrough;
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case TASK_STATE_ARMED:
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spin_unlock_bh(&task->state_lock);
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return;
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default:
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spin_unlock_bh(&task->state_lock);
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pr_warn("%s failed with bad state %d\n", __func__, task->state);
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return;
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}
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do {
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cont = 0;
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ret = task->func(task->arg);
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spin_lock_bh(&task->state_lock);
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switch (task->state) {
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case TASK_STATE_BUSY:
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if (ret) {
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task->state = TASK_STATE_START;
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} else if (iterations--) {
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cont = 1;
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} else {
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/* reschedule the tasklet and exit
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* the loop to give up the cpu
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*/
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tasklet_schedule(&task->tasklet);
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task->state = TASK_STATE_START;
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}
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break;
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/* someone tried to run the task since the last time we called
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* func, so we will call one more time regardless of the
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* return value
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*/
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case TASK_STATE_ARMED:
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task->state = TASK_STATE_BUSY;
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cont = 1;
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break;
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default:
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pr_warn("%s failed with bad state %d\n", __func__,
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task->state);
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}
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spin_unlock_bh(&task->state_lock);
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} while (cont);
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task->ret = ret;
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}
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int rxe_init_task(struct rxe_task *task, void *arg, int (*func)(void *))
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{
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task->arg = arg;
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task->func = func;
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task->destroyed = false;
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tasklet_setup(&task->tasklet, rxe_do_task);
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task->state = TASK_STATE_START;
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spin_lock_init(&task->state_lock);
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return 0;
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}
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void rxe_cleanup_task(struct rxe_task *task)
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{
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bool idle;
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/*
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* Mark the task, then wait for it to finish. It might be
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* running in a non-tasklet (direct call) context.
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*/
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task->destroyed = true;
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do {
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spin_lock_bh(&task->state_lock);
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idle = (task->state == TASK_STATE_START);
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spin_unlock_bh(&task->state_lock);
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} while (!idle);
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tasklet_kill(&task->tasklet);
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}
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void rxe_run_task(struct rxe_task *task)
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{
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if (task->destroyed)
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return;
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rxe_do_task(&task->tasklet);
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}
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void rxe_sched_task(struct rxe_task *task)
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{
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if (task->destroyed)
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return;
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tasklet_schedule(&task->tasklet);
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}
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void rxe_disable_task(struct rxe_task *task)
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{
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tasklet_disable(&task->tasklet);
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}
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void rxe_enable_task(struct rxe_task *task)
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{
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tasklet_enable(&task->tasklet);
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}
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