/* * 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); } /* Stop the error handler. */ if (ud->event & USBIP_EH_BYE) usbip_dbg_eh("removed %p\n", ud); 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);