diff options
Diffstat (limited to 'drivers/usb/usbip/usbip_event.c')
| -rw-r--r-- | drivers/usb/usbip/usbip_event.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/drivers/usb/usbip/usbip_event.c b/drivers/usb/usbip/usbip_event.c new file mode 100644 index 000000000..086ca76dd --- /dev/null +++ b/drivers/usb/usbip/usbip_event.c @@ -0,0 +1,197 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2003-2008 Takahiro Hirofuchi + * Copyright (C) 2015 Nobuo Iwata + */ + +#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); + + mutex_lock(&ud->sysfs_lock); + /* + * 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); + } + mutex_unlock(&ud->sysfs_lock); + + 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); |