| // SPDX-License-Identifier: GPL-2.0+ |
| /* |
| * Copyright (C) 2003-2008 Takahiro Hirofuchi |
| * Copyright (C) 2015 Nobuo Iwata |
| * |
| * This 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 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. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, |
| * USA. |
| */ |
| |
| #include <linux/kthread.h> |
| #include <linux/export.h> |
| #include <linux/slab.h> |
| #include <linux/workqueue.h> |
| |
| #include "usbip_common.h" |
| |
| struct usbip_event { |
| struct list_head node; |
| struct usbip_device *ud; |
| }; |
| |
| static DEFINE_SPINLOCK(event_lock); |
| static LIST_HEAD(event_list); |
| |
| static void set_event(struct usbip_device *ud, unsigned long event) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&ud->lock, flags); |
| ud->event |= event; |
| spin_unlock_irqrestore(&ud->lock, flags); |
| } |
| |
| static void unset_event(struct usbip_device *ud, unsigned long event) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&ud->lock, flags); |
| ud->event &= ~event; |
| spin_unlock_irqrestore(&ud->lock, flags); |
| } |
| |
| static struct usbip_device *get_event(void) |
| { |
| struct usbip_event *ue = NULL; |
| struct usbip_device *ud = NULL; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&event_lock, flags); |
| if (!list_empty(&event_list)) { |
| ue = list_first_entry(&event_list, struct usbip_event, node); |
| list_del(&ue->node); |
| } |
| spin_unlock_irqrestore(&event_lock, flags); |
| |
| if (ue) { |
| ud = ue->ud; |
| kfree(ue); |
| } |
| return ud; |
| } |
| |
| static struct task_struct *worker_context; |
| |
| static void event_handler(struct work_struct *work) |
| { |
| struct usbip_device *ud; |
| |
| if (worker_context == NULL) { |
| worker_context = current; |
| } |
| |
| while ((ud = get_event()) != NULL) { |
| usbip_dbg_eh("pending event %lx\n", ud->event); |
| |
| /* |
| * NOTE: shutdown must come first. |
| * Shutdown the device. |
| */ |
| if (ud->event & USBIP_EH_SHUTDOWN) { |
| ud->eh_ops.shutdown(ud); |
| unset_event(ud, USBIP_EH_SHUTDOWN); |
| } |
| |
| /* Reset the device. */ |
| if (ud->event & USBIP_EH_RESET) { |
| ud->eh_ops.reset(ud); |
| unset_event(ud, USBIP_EH_RESET); |
| } |
| |
| /* Mark the device as unusable. */ |
| if (ud->event & USBIP_EH_UNUSABLE) { |
| ud->eh_ops.unusable(ud); |
| unset_event(ud, USBIP_EH_UNUSABLE); |
| } |
| |
| wake_up(&ud->eh_waitq); |
| } |
| } |
| |
| int usbip_start_eh(struct usbip_device *ud) |
| { |
| init_waitqueue_head(&ud->eh_waitq); |
| ud->event = 0; |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(usbip_start_eh); |
| |
| void usbip_stop_eh(struct usbip_device *ud) |
| { |
| unsigned long pending = ud->event & ~USBIP_EH_BYE; |
| |
| if (!(ud->event & USBIP_EH_BYE)) |
| usbip_dbg_eh("usbip_eh stopping but not removed\n"); |
| |
| if (pending) |
| usbip_dbg_eh("usbip_eh waiting completion %lx\n", pending); |
| |
| wait_event_interruptible(ud->eh_waitq, !(ud->event & ~USBIP_EH_BYE)); |
| usbip_dbg_eh("usbip_eh has stopped\n"); |
| } |
| EXPORT_SYMBOL_GPL(usbip_stop_eh); |
| |
| #define WORK_QUEUE_NAME "usbip_event" |
| |
| static struct workqueue_struct *usbip_queue; |
| static DECLARE_WORK(usbip_work, event_handler); |
| |
| int usbip_init_eh(void) |
| { |
| usbip_queue = create_singlethread_workqueue(WORK_QUEUE_NAME); |
| if (usbip_queue == NULL) { |
| pr_err("failed to create usbip_event\n"); |
| return -ENOMEM; |
| } |
| return 0; |
| } |
| |
| void usbip_finish_eh(void) |
| { |
| flush_workqueue(usbip_queue); |
| destroy_workqueue(usbip_queue); |
| usbip_queue = NULL; |
| } |
| |
| void usbip_event_add(struct usbip_device *ud, unsigned long event) |
| { |
| struct usbip_event *ue; |
| unsigned long flags; |
| |
| if (ud->event & USBIP_EH_BYE) |
| return; |
| |
| set_event(ud, event); |
| |
| spin_lock_irqsave(&event_lock, flags); |
| |
| list_for_each_entry_reverse(ue, &event_list, node) { |
| if (ue->ud == ud) |
| goto out; |
| } |
| |
| ue = kmalloc(sizeof(struct usbip_event), GFP_ATOMIC); |
| if (ue == NULL) |
| goto out; |
| |
| ue->ud = ud; |
| |
| list_add_tail(&ue->node, &event_list); |
| queue_work(usbip_queue, &usbip_work); |
| |
| out: |
| spin_unlock_irqrestore(&event_lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(usbip_event_add); |
| |
| int usbip_event_happened(struct usbip_device *ud) |
| { |
| int happened = 0; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&ud->lock, flags); |
| if (ud->event != 0) |
| happened = 1; |
| spin_unlock_irqrestore(&ud->lock, flags); |
| |
| return happened; |
| } |
| EXPORT_SYMBOL_GPL(usbip_event_happened); |
| |
| int usbip_in_eh(struct task_struct *task) |
| { |
| if (task == worker_context) |
| return 1; |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(usbip_in_eh); |