From 863981e96738983919de841ec669e157e6bdaeb0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Sun, 11 Sep 2016 04:34:46 -0300 Subject: Linux-libre 4.7.1-gnu --- drivers/usb/usbip/usbip_event.c | 168 ++++++++++++++++++++++++++++++---------- 1 file changed, 126 insertions(+), 42 deletions(-) (limited to 'drivers/usb/usbip/usbip_event.c') diff --git a/drivers/usb/usbip/usbip_event.c b/drivers/usb/usbip/usbip_event.c index 2580a32bc..f1635662c 100644 --- a/drivers/usb/usbip/usbip_event.c +++ b/drivers/usb/usbip/usbip_event.c @@ -1,5 +1,6 @@ /* * 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 @@ -19,17 +20,68 @@ #include #include +#include +#include #include "usbip_common.h" -static int event_handler(struct usbip_device *ud) +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) { - usbip_dbg_eh("enter\n"); + unsigned long flags; - /* - * Events are handled by only this thread. - */ - while (usbip_event_happened(ud)) { + 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); /* @@ -38,79 +90,102 @@ static int event_handler(struct usbip_device *ud) */ if (ud->event & USBIP_EH_SHUTDOWN) { ud->eh_ops.shutdown(ud); - ud->event &= ~USBIP_EH_SHUTDOWN; + unset_event(ud, USBIP_EH_SHUTDOWN); } /* Reset the device. */ if (ud->event & USBIP_EH_RESET) { ud->eh_ops.reset(ud); - ud->event &= ~USBIP_EH_RESET; + unset_event(ud, USBIP_EH_RESET); } /* Mark the device as unusable. */ if (ud->event & USBIP_EH_UNUSABLE) { ud->eh_ops.unusable(ud); - ud->event &= ~USBIP_EH_UNUSABLE; + unset_event(ud, USBIP_EH_UNUSABLE); } /* Stop the error handler. */ if (ud->event & USBIP_EH_BYE) - return -1; + 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); -static int event_handler_loop(void *data) +void usbip_stop_eh(struct usbip_device *ud) { - struct usbip_device *ud = data; + unsigned long pending = ud->event & ~USBIP_EH_BYE; - while (!kthread_should_stop()) { - wait_event_interruptible(ud->eh_waitq, - usbip_event_happened(ud) || - kthread_should_stop()); - usbip_dbg_eh("wakeup\n"); + if (!(ud->event & USBIP_EH_BYE)) + usbip_dbg_eh("usbip_eh stopping but not removed\n"); - if (event_handler(ud) < 0) - break; - } + if (pending) + usbip_dbg_eh("usbip_eh waiting completion %lx\n", pending); - return 0; + 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); -int usbip_start_eh(struct usbip_device *ud) -{ - init_waitqueue_head(&ud->eh_waitq); - ud->event = 0; +#define WORK_QUEUE_NAME "usbip_event" - 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); - } +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; } -EXPORT_SYMBOL_GPL(usbip_start_eh); -void usbip_stop_eh(struct usbip_device *ud) +void usbip_finish_eh(void) { - if (ud->eh == current) - return; /* do not wait for myself */ - - kthread_stop(ud->eh); - usbip_dbg_eh("usbip_eh has finished\n"); + flush_workqueue(usbip_queue); + destroy_workqueue(usbip_queue); + usbip_queue = NULL; } -EXPORT_SYMBOL_GPL(usbip_stop_eh); void usbip_event_add(struct usbip_device *ud, unsigned long event) { + struct usbip_event *ue; unsigned long flags; - spin_lock_irqsave(&ud->lock, flags); - ud->event |= event; - wake_up(&ud->eh_waitq); - spin_unlock_irqrestore(&ud->lock, 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); @@ -127,3 +202,12 @@ int usbip_event_happened(struct usbip_device *ud) 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); -- cgit v1.2.3-54-g00ecf