[linux-2.6-block.git] / drivers / usb / usbip / usbip_event.c

// 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);

		/*
		 * 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);
Commit	Line	Data
5fd54ace	1	// SPDX-License-Identifier: GPL-2.0+
05a1f28e TH	2	/*
05a1f28e TH	3	* Copyright (C) 2003-2008 Takahiro Hirofuchi
bb7871ad	4	* Copyright (C) 2015 Nobuo Iwata
05a1f28e TH	5	*/
05a1f28e TH	6
b8868e45	7	#include <linux/kthread.h>
8e336a72	8	#include <linux/export.h>
bb7871ad NI	9	#include <linux/slab.h>
bb7871ad NI	10	#include <linux/workqueue.h>
7aaacb43	11
0f79847c	12	#include "usbip_common.h"
05a1f28e	13
bb7871ad NI	14	struct usbip_event {
	15	struct list_head node;
	16	struct usbip_device *ud;
	17	};
	18
	19	static DEFINE_SPINLOCK(event_lock);
	20	static LIST_HEAD(event_list);
	21
	22	static void set_event(struct usbip_device *ud, unsigned long event)
05a1f28e	23	{
bb7871ad	24	unsigned long flags;
05a1f28e	25
bb7871ad NI	26	spin_lock_irqsave(&ud->lock, flags);
	27	ud->event \|= event;
	28	spin_unlock_irqrestore(&ud->lock, flags);
	29	}
	30
	31	static void unset_event(struct usbip_device *ud, unsigned long event)
	32	{
	33	unsigned long flags;
	34
	35	spin_lock_irqsave(&ud->lock, flags);
	36	ud->event &= ~event;
	37	spin_unlock_irqrestore(&ud->lock, flags);
	38	}
	39
	40	static struct usbip_device *get_event(void)
	41	{
	42	struct usbip_event *ue = NULL;
	43	struct usbip_device *ud = NULL;
	44	unsigned long flags;
	45
	46	spin_lock_irqsave(&event_lock, flags);
	47	if (!list_empty(&event_list)) {
	48	ue = list_first_entry(&event_list, struct usbip_event, node);
	49	list_del(&ue->node);
	50	}
	51	spin_unlock_irqrestore(&event_lock, flags);
	52
	53	if (ue) {
	54	ud = ue->ud;
	55	kfree(ue);
	56	}
	57	return ud;
	58	}
	59
	60	static struct task_struct *worker_context;
	61
	62	static void event_handler(struct work_struct *work)
	63	{
	64	struct usbip_device *ud;
	65
	66	if (worker_context == NULL) {
	67	worker_context = current;
	68	}
	69
	70	while ((ud = get_event()) != NULL) {
b8868e45	71	usbip_dbg_eh("pending event %lx\n", ud->event);
05a1f28e TH	72
	73	/*
	74	* NOTE: shutdown must come first.
	75	* Shutdown the device.
	76	*/
	77	if (ud->event & USBIP_EH_SHUTDOWN) {
	78	ud->eh_ops.shutdown(ud);
bb7871ad	79	unset_event(ud, USBIP_EH_SHUTDOWN);
05a1f28e TH	80	}
05a1f28e TH	81
05a1f28e TH	82	/* Reset the device. */
	83	if (ud->event & USBIP_EH_RESET) {
	84	ud->eh_ops.reset(ud);
bb7871ad	85	unset_event(ud, USBIP_EH_RESET);
05a1f28e TH	86	}
	87
	88	/* Mark the device as unusable. */
	89	if (ud->event & USBIP_EH_UNUSABLE) {
	90	ud->eh_ops.unusable(ud);
bb7871ad	91	unset_event(ud, USBIP_EH_UNUSABLE);
05a1f28e TH	92	}
05a1f28e TH	93
bb7871ad	94	wake_up(&ud->eh_waitq);
05a1f28e	95	}
bb7871ad	96	}
05a1f28e	97
bb7871ad NI	98	int usbip_start_eh(struct usbip_device *ud)
	99	{
	100	init_waitqueue_head(&ud->eh_waitq);
	101	ud->event = 0;
05a1f28e TH	102	return 0;
05a1f28e TH	103	}
bb7871ad	104	EXPORT_SYMBOL_GPL(usbip_start_eh);
05a1f28e	105
bb7871ad	106	void usbip_stop_eh(struct usbip_device *ud)
05a1f28e	107	{
bb7871ad	108	unsigned long pending = ud->event & ~USBIP_EH_BYE;
05a1f28e	109
bb7871ad NI	110	if (!(ud->event & USBIP_EH_BYE))
bb7871ad NI	111	usbip_dbg_eh("usbip_eh stopping but not removed\n");
05a1f28e	112
bb7871ad NI	113	if (pending)
bb7871ad NI	114	usbip_dbg_eh("usbip_eh waiting completion %lx\n", pending);
0f79847c	115
bb7871ad NI	116	wait_event_interruptible(ud->eh_waitq, !(ud->event & ~USBIP_EH_BYE));
bb7871ad NI	117	usbip_dbg_eh("usbip_eh has stopped\n");
05a1f28e	118	}
bb7871ad	119	EXPORT_SYMBOL_GPL(usbip_stop_eh);
05a1f28e	120
bb7871ad	121	#define WORK_QUEUE_NAME "usbip_event"
05a1f28e	122
bb7871ad NI	123	static struct workqueue_struct *usbip_queue;
bb7871ad NI	124	static DECLARE_WORK(usbip_work, event_handler);
0f79847c	125
bb7871ad NI	126	int usbip_init_eh(void)
	127	{
	128	usbip_queue = create_singlethread_workqueue(WORK_QUEUE_NAME);
	129	if (usbip_queue == NULL) {
	130	pr_err("failed to create usbip_event\n");
	131	return -ENOMEM;
	132	}
b8868e45	133	return 0;
05a1f28e	134	}
05a1f28e	135
bb7871ad	136	void usbip_finish_eh(void)
05a1f28e	137	{
bb7871ad NI	138	flush_workqueue(usbip_queue);
	139	destroy_workqueue(usbip_queue);
	140	usbip_queue = NULL;
05a1f28e	141	}
05a1f28e TH	142
	143	void usbip_event_add(struct usbip_device *ud, unsigned long event)
	144	{
bb7871ad	145	struct usbip_event *ue;
dcf14779 HY	146	unsigned long flags;
dcf14779 HY	147
bb7871ad NI	148	if (ud->event & USBIP_EH_BYE)
	149	return;
	150
	151	set_event(ud, event);
	152
	153	spin_lock_irqsave(&event_lock, flags);
	154
	155	list_for_each_entry_reverse(ue, &event_list, node) {
	156	if (ue->ud == ud)
	157	goto out;
	158	}
	159
	160	ue = kmalloc(sizeof(struct usbip_event), GFP_ATOMIC);
	161	if (ue == NULL)
	162	goto out;
	163
	164	ue->ud = ud;
	165
	166	list_add_tail(&ue->node, &event_list);
	167	queue_work(usbip_queue, &usbip_work);
	168
	169	out:
	170	spin_unlock_irqrestore(&event_lock, flags);
05a1f28e TH	171	}
	172	EXPORT_SYMBOL_GPL(usbip_event_add);
	173
b8868e45	174	int usbip_event_happened(struct usbip_device *ud)
05a1f28e	175	{
b8868e45	176	int happened = 0;
21619792	177	unsigned long flags;
05a1f28e	178
21619792	179	spin_lock_irqsave(&ud->lock, flags);
05a1f28e	180	if (ud->event != 0)
b8868e45	181	happened = 1;
21619792	182	spin_unlock_irqrestore(&ud->lock, flags);
05a1f28e	183
b8868e45	184	return happened;
05a1f28e	185	}
b8868e45	186	EXPORT_SYMBOL_GPL(usbip_event_happened);
bb7871ad NI	187
	188	int usbip_in_eh(struct task_struct *task)
	189	{
	190	if (task == worker_context)
	191	return 1;
	192
	193	return 0;
	194	}
	195	EXPORT_SYMBOL_GPL(usbip_in_eh);