diff options
Diffstat (limited to 'drivers/staging/dst/thread_pool.c')
-rw-r--r-- | drivers/staging/dst/thread_pool.c | 348 |
1 files changed, 0 insertions, 348 deletions
diff --git a/drivers/staging/dst/thread_pool.c b/drivers/staging/dst/thread_pool.c deleted file mode 100644 index 29a82b2..0000000 --- a/drivers/staging/dst/thread_pool.c +++ /dev/null @@ -1,348 +0,0 @@ -/* - * 2007+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net> - * All rights reserved. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - */ - -#include <linux/kernel.h> -#include <linux/dst.h> -#include <linux/kthread.h> -#include <linux/slab.h> - -/* - * Thread pool abstraction allows to schedule a work to be performed - * on behalf of kernel thread. One does not operate with threads itself, - * instead user provides setup and cleanup callbacks for thread pool itself, - * and action and cleanup callbacks for each submitted work. - * - * Each worker has private data initialized at creation time and data, - * provided by user at scheduling time. - * - * When action is being performed, thread can not be used by other users, - * instead they will sleep until there is free thread to pick their work. - */ -struct thread_pool_worker { - struct list_head worker_entry; - - struct task_struct *thread; - - struct thread_pool *pool; - - int error; - int has_data; - int need_exit; - unsigned int id; - - wait_queue_head_t wait; - - void *private; - void *schedule_data; - - int (*action)(void *private, void *schedule_data); - void (*cleanup)(void *private); -}; - -static void thread_pool_exit_worker(struct thread_pool_worker *w) -{ - kthread_stop(w->thread); - - w->cleanup(w->private); - kfree(w); -} - -/* - * Called to mark thread as ready and allow users to schedule new work. - */ -static void thread_pool_worker_make_ready(struct thread_pool_worker *w) -{ - struct thread_pool *p = w->pool; - - mutex_lock(&p->thread_lock); - - if (!w->need_exit) { - list_move_tail(&w->worker_entry, &p->ready_list); - w->has_data = 0; - mutex_unlock(&p->thread_lock); - - wake_up(&p->wait); - } else { - p->thread_num--; - list_del(&w->worker_entry); - mutex_unlock(&p->thread_lock); - - thread_pool_exit_worker(w); - } -} - -/* - * Thread action loop: waits until there is new work. - */ -static int thread_pool_worker_func(void *data) -{ - struct thread_pool_worker *w = data; - - while (!kthread_should_stop()) { - wait_event_interruptible(w->wait, - kthread_should_stop() || w->has_data); - - if (kthread_should_stop()) - break; - - if (!w->has_data) - continue; - - w->action(w->private, w->schedule_data); - thread_pool_worker_make_ready(w); - } - - return 0; -} - -/* - * Remove single worker without specifying which one. - */ -void thread_pool_del_worker(struct thread_pool *p) -{ - struct thread_pool_worker *w = NULL; - - while (!w && p->thread_num) { - wait_event(p->wait, !list_empty(&p->ready_list) || - !p->thread_num); - - dprintk("%s: locking list_empty: %d, thread_num: %d.\n", - __func__, list_empty(&p->ready_list), - p->thread_num); - - mutex_lock(&p->thread_lock); - if (!list_empty(&p->ready_list)) { - w = list_first_entry(&p->ready_list, - struct thread_pool_worker, - worker_entry); - - dprintk("%s: deleting w: %p, thread_num: %d, " - "list: %p [%p.%p].\n", __func__, - w, p->thread_num, &p->ready_list, - p->ready_list.prev, p->ready_list.next); - - p->thread_num--; - list_del(&w->worker_entry); - } - mutex_unlock(&p->thread_lock); - } - - if (w) - thread_pool_exit_worker(w); - dprintk("%s: deleted w: %p, thread_num: %d.\n", - __func__, w, p->thread_num); -} - -/* - * Remove a worker with given ID. - */ -void thread_pool_del_worker_id(struct thread_pool *p, unsigned int id) -{ - struct thread_pool_worker *w; - int found = 0; - - mutex_lock(&p->thread_lock); - list_for_each_entry(w, &p->ready_list, worker_entry) { - if (w->id == id) { - found = 1; - p->thread_num--; - list_del(&w->worker_entry); - break; - } - } - - if (!found) { - list_for_each_entry(w, &p->active_list, worker_entry) { - if (w->id == id) { - w->need_exit = 1; - break; - } - } - } - mutex_unlock(&p->thread_lock); - - if (found) - thread_pool_exit_worker(w); -} - -/* - * Add new worker thread with given parameters. - * If initialization callback fails, return error. - */ -int thread_pool_add_worker(struct thread_pool *p, - char *name, - unsigned int id, - void *(*init)(void *private), - void (*cleanup)(void *private), - void *private) -{ - struct thread_pool_worker *w; - int err = -ENOMEM; - - w = kzalloc(sizeof(struct thread_pool_worker), GFP_KERNEL); - if (!w) - goto err_out_exit; - - w->pool = p; - init_waitqueue_head(&w->wait); - w->cleanup = cleanup; - w->id = id; - - w->thread = kthread_run(thread_pool_worker_func, w, "%s", name); - if (IS_ERR(w->thread)) { - err = PTR_ERR(w->thread); - goto err_out_free; - } - - w->private = init(private); - if (IS_ERR(w->private)) { - err = PTR_ERR(w->private); - goto err_out_stop_thread; - } - - mutex_lock(&p->thread_lock); - list_add_tail(&w->worker_entry, &p->ready_list); - p->thread_num++; - mutex_unlock(&p->thread_lock); - - return 0; - -err_out_stop_thread: - kthread_stop(w->thread); -err_out_free: - kfree(w); -err_out_exit: - return err; -} - -/* - * Destroy the whole pool. - */ -void thread_pool_destroy(struct thread_pool *p) -{ - while (p->thread_num) { - dprintk("%s: num: %d.\n", __func__, p->thread_num); - thread_pool_del_worker(p); - } - - kfree(p); -} - -/* - * Create a pool with given number of threads. - * They will have sequential IDs started from zero. - */ -struct thread_pool *thread_pool_create(int num, char *name, - void *(*init)(void *private), - void (*cleanup)(void *private), - void *private) -{ - struct thread_pool_worker *w, *tmp; - struct thread_pool *p; - int err = -ENOMEM; - int i; - - p = kzalloc(sizeof(struct thread_pool), GFP_KERNEL); - if (!p) - goto err_out_exit; - - init_waitqueue_head(&p->wait); - mutex_init(&p->thread_lock); - INIT_LIST_HEAD(&p->ready_list); - INIT_LIST_HEAD(&p->active_list); - p->thread_num = 0; - - for (i = 0; i < num; ++i) { - err = thread_pool_add_worker(p, name, i, init, - cleanup, private); - if (err) - goto err_out_free_all; - } - - return p; - -err_out_free_all: - list_for_each_entry_safe(w, tmp, &p->ready_list, worker_entry) { - list_del(&w->worker_entry); - thread_pool_exit_worker(w); - } - kfree(p); -err_out_exit: - return ERR_PTR(err); -} - -/* - * Schedule execution of the action on a given thread, - * provided ID pointer has to match previously stored - * private data. - */ -int thread_pool_schedule_private(struct thread_pool *p, - int (*setup)(void *private, void *data), - int (*action)(void *private, void *data), - void *data, long timeout, void *id) -{ - struct thread_pool_worker *w, *tmp, *worker = NULL; - int err = 0; - - while (!worker && !err) { - timeout = wait_event_interruptible_timeout(p->wait, - !list_empty(&p->ready_list), - timeout); - - if (!timeout) { - err = -ETIMEDOUT; - break; - } - - worker = NULL; - mutex_lock(&p->thread_lock); - list_for_each_entry_safe(w, tmp, &p->ready_list, worker_entry) { - if (id && id != w->private) - continue; - - worker = w; - - list_move_tail(&w->worker_entry, &p->active_list); - - err = setup(w->private, data); - if (!err) { - w->schedule_data = data; - w->action = action; - w->has_data = 1; - wake_up(&w->wait); - } else { - list_move_tail(&w->worker_entry, - &p->ready_list); - } - - break; - } - mutex_unlock(&p->thread_lock); - } - - return err; -} - -/* - * Schedule execution on arbitrary thread from the pool. - */ -int thread_pool_schedule(struct thread_pool *p, - int (*setup)(void *private, void *data), - int (*action)(void *private, void *data), - void *data, long timeout) -{ - return thread_pool_schedule_private(p, setup, - action, data, timeout, NULL); -} |