/* * Copyright (C) 2003-2008 Takahiro Hirofuchi * * 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 "usbip_common.h" static int event_handler(struct usbip_device *ud) { usbip_dbg_eh("enter\n"); /* * Events are handled by only this thread. */ while (usbip_event_happened(ud)) { 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); ud->event &= ~USBIP_EH_SHUTDOWN; } /* Reset the device. */ if (ud->event & USBIP_EH_RESET) { ud->eh_ops.reset(ud); ud->event &= ~USBIP_EH_RESET; } /* Mark the device as unusable. */ if (ud->event & USBIP_EH_UNUSABLE) { ud->eh_ops.unusable(ud); ud->event &= ~USBIP_EH_UNUSABLE; } /* Stop the error handler. */ if (ud->event & USBIP_EH_BYE) return -1; } return 0; } static int event_handler_loop(void *data) { struct usbip_device *ud = data; while (!kthread_should_stop()) { wait_event_interruptible(ud->eh_waitq, usbip_event_happened(ud) || kthread_should_stop()); usbip_dbg_eh("wakeup\n"); if (event_handler(ud) < 0) break; } return 0; } int usbip_start_eh(struct usbip_device *ud) { init_waitqueue_head(&ud->eh_waitq); ud->event = 0; ud->eh = kthread_run(event_handler_loop, ud, "usbip_eh"); if (IS_ERR(ud->eh)) { pr_warn("Unable to start control thread\n"); return PTR_ERR(ud->eh); } return 0; } EXPORT_SYMBOL_GPL(usbip_start_eh); void usbip_stop_eh(struct usbip_device *ud) { if (ud->eh == current) return; /* do not wait for myself */ kthread_stop(ud->eh); usbip_dbg_eh("usbip_eh has finished\n"); } EXPORT_SYMBOL_GPL(usbip_stop_eh); void usbip_event_add(struct usbip_device *ud, unsigned long event) { unsigned long flags; spin_lock_irqsave(&ud->lock, flags); ud->event |= event; wake_up(&ud->eh_waitq); spin_unlock_irqrestore(&ud->lock, flags); } EXPORT_SYMBOL_GPL(usbip_event_add); int usbip_event_happened(struct usbip_device *ud) { int happened = 0; spin_lock(&ud->lock); if (ud->event != 0) happened = 1; spin_unlock(&ud->lock); return happened; } EXPORT_SYMBOL_GPL(usbip_event_happened);