diff options
Diffstat (limited to 'drivers/infiniband/sw/rxe/rxe_task.c')
| -rw-r--r-- | drivers/infiniband/sw/rxe/rxe_task.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/drivers/infiniband/sw/rxe/rxe_task.c b/drivers/infiniband/sw/rxe/rxe_task.c new file mode 100644 index 000000000..08f05ac5f --- /dev/null +++ b/drivers/infiniband/sw/rxe/rxe_task.c @@ -0,0 +1,173 @@ +/* + * 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(void *obj, struct rxe_task *task, + void *arg, int (*func)(void *), char *name) +{ + task->obj = obj; + task->arg = arg; + task->func = func; + snprintf(task->name, sizeof(task->name), "%s", name); + 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); +} |