A 'task' is a short function that returns 0 as long as it needs to be called again. rxe tasks are based on the kernel's tasklet infrastructure.
Signed-off-by: Kamal Heib <kam...@mellanox.com> Signed-off-by: Amir Vadai <am...@mellanox.com> Reviewed-by: Haggai Eran <hagg...@mellanox.com> --- drivers/staging/rxe/rxe_task.c | 154 +++++++++++++++++++++++++++++++++++++++++ drivers/staging/rxe/rxe_task.h | 95 +++++++++++++++++++++++++ 2 files changed, 249 insertions(+) create mode 100644 drivers/staging/rxe/rxe_task.c create mode 100644 drivers/staging/rxe/rxe_task.h diff --git a/drivers/staging/rxe/rxe_task.c b/drivers/staging/rxe/rxe_task.c new file mode 100644 index 0000000..162fa1a --- /dev/null +++ b/drivers/staging/rxe/rxe_task.c @@ -0,0 +1,154 @@ +/* + * Copyright (c) 2015 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 to */ + case TASK_STATE_ARMED: + spin_unlock_irqrestore(&task->state_lock, flags); + return; + + default: + spin_unlock_irqrestore(&task->state_lock, flags); + pr_warn("bad state = %d in rxe_do_task\n", 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("bad state = %d in rxe_do_task\n", + 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); + + 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) +{ + tasklet_kill(&task->tasklet); +} + +void rxe_run_task(struct rxe_task *task, int sched) +{ + 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); +} diff --git a/drivers/staging/rxe/rxe_task.h b/drivers/staging/rxe/rxe_task.h new file mode 100644 index 0000000..1183662 --- /dev/null +++ b/drivers/staging/rxe/rxe_task.h @@ -0,0 +1,95 @@ +/* + * Copyright (c) 2015 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. + */ + +#ifndef RXE_TASK_H +#define RXE_TASK_H + +enum { + TASK_STATE_START = 0, + TASK_STATE_BUSY = 1, + TASK_STATE_ARMED = 2, +}; + +/* + * data structure to describe a 'task' which is a short + * function that returns 0 as long as it needs to be + * called again. + */ +struct rxe_task { + void *obj; + struct tasklet_struct tasklet; + int state; + spinlock_t state_lock; /* spinlock for task state */ + void *arg; + int (*func)(void *arg); + int ret; + char name[16]; +}; + +/* + * init rxe_task structure + * arg => parameter to pass to fcn + * fcn => function to call until it returns != 0 + */ +int rxe_init_task(void *obj, struct rxe_task *task, + void *arg, int (*func)(void *), char *name); + +/* cleanup task */ +void rxe_cleanup_task(struct rxe_task *task); + +/* + * raw call to func in loop without any checking + * can call when tasklets are disabled + */ +int __rxe_do_task(struct rxe_task *task); + +/* + * common function called by any of the main tasklets + * If there is any chance that there is additional + * work to do someone must reschedule the task before + * leaving + */ +void rxe_do_task(unsigned long data); + +/* run a task, else schedule it to run as a tasklet, The decision + * to run or schedule tasklet is based on the parameter sched. + * */ +void rxe_run_task(struct rxe_task *task, int sched); + +/* keep a task from scheduling */ +void rxe_disable_task(struct rxe_task *task); + +/* allow task to run */ +void rxe_enable_task(struct rxe_task *task); + +#endif /* RXE_TASK_H */ -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html