[mirror_ubuntu-focal-kernel.git] / drivers / usb / mon / mon_main.c

/*
 * The USB Monitor, inspired by Dave Harding's USBMon.
 *
 * mon_main.c: Main file, module initiation and exit, registrations, etc.
 *
 * Copyright (C) 2005 Pete Zaitcev (zaitcev@redhat.com)
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/notifier.h>
#include <linux/mutex.h>

#include "usb_mon.h"
#include "../core/hcd.h"

static void mon_stop(struct mon_bus *mbus);
static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus);
static void mon_bus_drop(struct kref *r);
static void mon_bus_init(struct usb_bus *ubus);

DEFINE_MUTEX(mon_lock);

struct mon_bus mon_bus0;		/* Pseudo bus meaning "all buses" */
static LIST_HEAD(mon_buses);		/* All buses we know: struct mon_bus */

/*
 * Link a reader into the bus.
 *
 * This must be called with mon_lock taken because of mbus->ref.
 */
void mon_reader_add(struct mon_bus *mbus, struct mon_reader *r)
{
	unsigned long flags;
	struct list_head *p;

	spin_lock_irqsave(&mbus->lock, flags);
	if (mbus->nreaders == 0) {
		if (mbus == &mon_bus0) {
			list_for_each (p, &mon_buses) {
				struct mon_bus *m1;
				m1 = list_entry(p, struct mon_bus, bus_link);
				m1->u_bus->monitored = 1;
			}
		} else {
			mbus->u_bus->monitored = 1;
		}
	}
	mbus->nreaders++;
	list_add_tail(&r->r_link, &mbus->r_list);
	spin_unlock_irqrestore(&mbus->lock, flags);

	kref_get(&mbus->ref);
}

/*
 * Unlink reader from the bus.
 *
 * This is called with mon_lock taken, so we can decrement mbus->ref.
 */
void mon_reader_del(struct mon_bus *mbus, struct mon_reader *r)
{
	unsigned long flags;

	spin_lock_irqsave(&mbus->lock, flags);
	list_del(&r->r_link);
	--mbus->nreaders;
	if (mbus->nreaders == 0)
		mon_stop(mbus);
	spin_unlock_irqrestore(&mbus->lock, flags);

	kref_put(&mbus->ref, mon_bus_drop);
}

/*
 */
static void mon_bus_submit(struct mon_bus *mbus, struct urb *urb)
{
	unsigned long flags;
	struct list_head *pos;
	struct mon_reader *r;

	spin_lock_irqsave(&mbus->lock, flags);
	mbus->cnt_events++;
	list_for_each (pos, &mbus->r_list) {
		r = list_entry(pos, struct mon_reader, r_link);
		r->rnf_submit(r->r_data, urb);
	}
	spin_unlock_irqrestore(&mbus->lock, flags);
	return;
}

static void mon_submit(struct usb_bus *ubus, struct urb *urb)
{
	struct mon_bus *mbus;

	if ((mbus = ubus->mon_bus) != NULL)
		mon_bus_submit(mbus, urb);
	mon_bus_submit(&mon_bus0, urb);
}

/*
 */
static void mon_bus_submit_error(struct mon_bus *mbus, struct urb *urb, int error)
{
	unsigned long flags;
	struct list_head *pos;
	struct mon_reader *r;

	spin_lock_irqsave(&mbus->lock, flags);
	mbus->cnt_events++;
	list_for_each (pos, &mbus->r_list) {
		r = list_entry(pos, struct mon_reader, r_link);
		r->rnf_error(r->r_data, urb, error);
	}
	spin_unlock_irqrestore(&mbus->lock, flags);
	return;
}

static void mon_submit_error(struct usb_bus *ubus, struct urb *urb, int error)
{
	struct mon_bus *mbus;

	if ((mbus = ubus->mon_bus) != NULL)
		mon_bus_submit_error(mbus, urb, error);
	mon_bus_submit_error(&mon_bus0, urb, error);
}

/*
 */
static void mon_bus_complete(struct mon_bus *mbus, struct urb *urb)
{
	unsigned long flags;
	struct list_head *pos;
	struct mon_reader *r;

	spin_lock_irqsave(&mbus->lock, flags);
	mbus->cnt_events++;
	list_for_each (pos, &mbus->r_list) {
		r = list_entry(pos, struct mon_reader, r_link);
		r->rnf_complete(r->r_data, urb);
	}
	spin_unlock_irqrestore(&mbus->lock, flags);
}

static void mon_complete(struct usb_bus *ubus, struct urb *urb)
{
	struct mon_bus *mbus;

	mbus = ubus->mon_bus;
	if (mbus == NULL) {
		/*
		 * This should not happen.
		 * At this point we do not even know the bus number...
		 */
		printk(KERN_ERR TAG ": Null mon bus in URB, pipe 0x%x\n",
		    urb->pipe);
		return;
	}

	mon_bus_complete(mbus, urb);
	mon_bus_complete(&mon_bus0, urb);
}

/* int (*unlink_urb) (struct urb *urb, int status); */

/*
 * Stop monitoring.
 */
static void mon_stop(struct mon_bus *mbus)
{
	struct usb_bus *ubus = mbus->u_bus;
	struct list_head *p;

	if (mbus == &mon_bus0) {
		list_for_each (p, &mon_buses) {
			mbus = list_entry(p, struct mon_bus, bus_link);
			/*
			 * We do not change nreaders here, so rely on mon_lock.
			 */
			if (mbus->nreaders == 0 && (ubus = mbus->u_bus) != NULL)
				ubus->monitored = 0;
		}
	} else {
		/*
		 * A stop can be called for a dissolved mon_bus in case of
		 * a reader staying across an rmmod foo_hcd, so test ->u_bus.
		 */
		if (mon_bus0.nreaders == 0 && (ubus = mbus->u_bus) != NULL) {
			ubus->monitored = 0;
			mb();
		}
	}
}

/*
 * Add a USB bus (usually by a modprobe foo-hcd)
 *
 * This does not return an error code because the core cannot care less
 * if monitoring is not established.
 */
static void mon_bus_add(struct usb_bus *ubus)
{
	mon_bus_init(ubus);
	mutex_lock(&mon_lock);
	if (mon_bus0.nreaders != 0)
		ubus->monitored = 1;
	mutex_unlock(&mon_lock);
}

/*
 * Remove a USB bus (either from rmmod foo-hcd or from a hot-remove event).
 */
static void mon_bus_remove(struct usb_bus *ubus)
{
	struct mon_bus *mbus = ubus->mon_bus;

	mutex_lock(&mon_lock);
	list_del(&mbus->bus_link);
	if (mbus->text_inited)
		mon_text_del(mbus);

	mon_dissolve(mbus, ubus);
	kref_put(&mbus->ref, mon_bus_drop);
	mutex_unlock(&mon_lock);
}

static int mon_notify(struct notifier_block *self, unsigned long action,
		      void *dev)
{
	switch (action) {
	case USB_BUS_ADD:
		mon_bus_add(dev);
		break;
	case USB_BUS_REMOVE:
		mon_bus_remove(dev);
	}
	return NOTIFY_OK;
}

static struct notifier_block mon_nb = {
	.notifier_call = 	mon_notify,
};

/*
 * Ops
 */
static struct usb_mon_operations mon_ops_0 = {
	.urb_submit =	mon_submit,
	.urb_submit_error = mon_submit_error,
	.urb_complete =	mon_complete,
};

/*
 * Tear usb_bus and mon_bus apart.
 */
static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus)
{

	if (ubus->monitored) {
		ubus->monitored = 0;
		mb();
	}

	ubus->mon_bus = NULL;
	mbus->u_bus = NULL;
	mb();

	/* We want synchronize_irq() here, but that needs an argument. */
}

/*
 */
static void mon_bus_drop(struct kref *r)
{
	struct mon_bus *mbus = container_of(r, struct mon_bus, ref);
	kfree(mbus);
}

/*
 * Initialize a bus for us:
 *  - allocate mon_bus
 *  - refcount USB bus struct
 *  - link
 */
static void mon_bus_init(struct usb_bus *ubus)
{
	struct mon_bus *mbus;

	if ((mbus = kzalloc(sizeof(struct mon_bus), GFP_KERNEL)) == NULL)
		goto err_alloc;
	kref_init(&mbus->ref);
	spin_lock_init(&mbus->lock);
	INIT_LIST_HEAD(&mbus->r_list);

	/*
	 * We don't need to take a reference to ubus, because we receive
	 * a notification if the bus is about to be removed.
	 */
	mbus->u_bus = ubus;
	ubus->mon_bus = mbus;

	mbus->text_inited = mon_text_add(mbus, ubus->busnum);
	// mon_bin_add(...)

	mutex_lock(&mon_lock);
	list_add_tail(&mbus->bus_link, &mon_buses);
	mutex_unlock(&mon_lock);
	return;

err_alloc:
	return;
}

static void mon_bus0_init(void)
{
	struct mon_bus *mbus = &mon_bus0;

	kref_init(&mbus->ref);
	spin_lock_init(&mbus->lock);
	INIT_LIST_HEAD(&mbus->r_list);

	mbus->text_inited = mon_text_add(mbus, 0);
	// mbus->bin_inited = mon_bin_add(mbus, 0);
}

/*
 * Search a USB bus by number. Notice that USB bus numbers start from one,
 * which we may later use to identify "all" with zero.
 *
 * This function must be called with mon_lock held.
 *
 * This is obviously inefficient and may be revised in the future.
 */
struct mon_bus *mon_bus_lookup(unsigned int num)
{
	struct list_head *p;
	struct mon_bus *mbus;

	if (num == 0) {
		return &mon_bus0;
	}
	list_for_each (p, &mon_buses) {
		mbus = list_entry(p, struct mon_bus, bus_link);
		if (mbus->u_bus->busnum == num) {
			return mbus;
		}
	}
	return NULL;
}

static int __init mon_init(void)
{
	struct usb_bus *ubus;
	int rc;

	if ((rc = mon_text_init()) != 0)
		goto err_text;
	if ((rc = mon_bin_init()) != 0)
		goto err_bin;

	mon_bus0_init();

	if (usb_mon_register(&mon_ops_0) != 0) {
		printk(KERN_NOTICE TAG ": unable to register with the core\n");
		rc = -ENODEV;
		goto err_reg;
	}
	// MOD_INC_USE_COUNT(which_module?);

	usb_register_notify(&mon_nb);

	mutex_lock(&usb_bus_list_lock);
	list_for_each_entry (ubus, &usb_bus_list, bus_list) {
		mon_bus_init(ubus);
	}
	mutex_unlock(&usb_bus_list_lock);
	return 0;

err_reg:
	mon_bin_exit();
err_bin:
	mon_text_exit();
err_text:
	return rc;
}

static void __exit mon_exit(void)
{
	struct mon_bus *mbus;
	struct list_head *p;

	usb_unregister_notify(&mon_nb);
	usb_mon_deregister();

	mutex_lock(&mon_lock);

	while (!list_empty(&mon_buses)) {
		p = mon_buses.next;
		mbus = list_entry(p, struct mon_bus, bus_link);
		list_del(p);

		if (mbus->text_inited)
			mon_text_del(mbus);

		/*
		 * This never happens, because the open/close paths in
		 * file level maintain module use counters and so rmmod fails
		 * before reaching here. However, better be safe...
		 */
		if (mbus->nreaders) {
			printk(KERN_ERR TAG
			    ": Outstanding opens (%d) on usb%d, leaking...\n",
			    mbus->nreaders, mbus->u_bus->busnum);
			atomic_set(&mbus->ref.refcount, 2);	/* Force leak */
		}

		mon_dissolve(mbus, mbus->u_bus);
		kref_put(&mbus->ref, mon_bus_drop);
	}

	mbus = &mon_bus0;
	if (mbus->text_inited)
		mon_text_del(mbus);

	mutex_unlock(&mon_lock);

	mon_text_exit();
	mon_bin_exit();
}

module_init(mon_init);
module_exit(mon_exit);

MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* The USB Monitor, inspired by Dave Harding's USBMon.
	3	*
	4	* mon_main.c: Main file, module initiation and exit, registrations, etc.
da5ca008 PZ	5	*
da5ca008 PZ	6	* Copyright (C) 2005 Pete Zaitcev (zaitcev@redhat.com)
1da177e4 LT	7	*/
	8
	9	#include <linux/kernel.h>
	10	#include <linux/module.h>
	11	#include <linux/usb.h>
72adaa96	12	#include <linux/notifier.h>
4186ecf8	13	#include <linux/mutex.h>
1da177e4 LT	14
	15	#include "usb_mon.h"
	16	#include "../core/hcd.h"
	17
1da177e4 LT	18	static void mon_stop(struct mon_bus *mbus);
	19	static void mon_dissolve(struct mon_bus mbus, struct usb_bus ubus);
	20	static void mon_bus_drop(struct kref *r);
6f23ee1f	21	static void mon_bus_init(struct usb_bus *ubus);
1da177e4	22
4186ecf8	23	DEFINE_MUTEX(mon_lock);
1da177e4	24
ecb658d3	25	struct mon_bus mon_bus0; /* Pseudo bus meaning "all buses" */
1da177e4 LT	26	static LIST_HEAD(mon_buses); /* All buses we know: struct mon_bus */
	27
	28	/*
	29	* Link a reader into the bus.
	30	*
	31	* This must be called with mon_lock taken because of mbus->ref.
	32	*/
	33	void mon_reader_add(struct mon_bus mbus, struct mon_reader r)
	34	{
	35	unsigned long flags;
ecb658d3	36	struct list_head *p;
1da177e4 LT	37
	38	spin_lock_irqsave(&mbus->lock, flags);
	39	if (mbus->nreaders == 0) {
ecb658d3 PZ	40	if (mbus == &mon_bus0) {
	41	list_for_each (p, &mon_buses) {
	42	struct mon_bus *m1;
	43	m1 = list_entry(p, struct mon_bus, bus_link);
	44	m1->u_bus->monitored = 1;
	45	}
	46	} else {
	47	mbus->u_bus->monitored = 1;
1da177e4	48	}
1da177e4 LT	49	}
	50	mbus->nreaders++;
	51	list_add_tail(&r->r_link, &mbus->r_list);
	52	spin_unlock_irqrestore(&mbus->lock, flags);
	53
	54	kref_get(&mbus->ref);
	55	}
	56
	57	/*
	58	* Unlink reader from the bus.
	59	*
	60	* This is called with mon_lock taken, so we can decrement mbus->ref.
	61	*/
	62	void mon_reader_del(struct mon_bus mbus, struct mon_reader r)
	63	{
	64	unsigned long flags;
	65
	66	spin_lock_irqsave(&mbus->lock, flags);
	67	list_del(&r->r_link);
	68	--mbus->nreaders;
	69	if (mbus->nreaders == 0)
	70	mon_stop(mbus);
	71	spin_unlock_irqrestore(&mbus->lock, flags);
	72
	73	kref_put(&mbus->ref, mon_bus_drop);
	74	}
	75
	76	/*
	77	*/
ecb658d3	78	static void mon_bus_submit(struct mon_bus mbus, struct urb urb)
1da177e4	79	{
1da177e4 LT	80	unsigned long flags;
	81	struct list_head *pos;
	82	struct mon_reader *r;
	83
1da177e4	84	spin_lock_irqsave(&mbus->lock, flags);
5b1c674d	85	mbus->cnt_events++;
1da177e4 LT	86	list_for_each (pos, &mbus->r_list) {
	87	r = list_entry(pos, struct mon_reader, r_link);
	88	r->rnf_submit(r->r_data, urb);
	89	}
1da177e4 LT	90	spin_unlock_irqrestore(&mbus->lock, flags);
1da177e4 LT	91	return;
ecb658d3	92	}
1da177e4	93
ecb658d3 PZ	94	static void mon_submit(struct usb_bus ubus, struct urb urb)
	95	{
	96	struct mon_bus *mbus;
	97
	98	if ((mbus = ubus->mon_bus) != NULL)
	99	mon_bus_submit(mbus, urb);
	100	mon_bus_submit(&mon_bus0, urb);
1da177e4 LT	101	}
	102
	103	/*
	104	*/
ecb658d3	105	static void mon_bus_submit_error(struct mon_bus mbus, struct urb urb, int error)
1da177e4	106	{
12e72fea PZ	107	unsigned long flags;
	108	struct list_head *pos;
	109	struct mon_reader *r;
1da177e4	110
12e72fea	111	spin_lock_irqsave(&mbus->lock, flags);
12e72fea PZ	112	mbus->cnt_events++;
	113	list_for_each (pos, &mbus->r_list) {
	114	r = list_entry(pos, struct mon_reader, r_link);
	115	r->rnf_error(r->r_data, urb, error);
	116	}
12e72fea	117	spin_unlock_irqrestore(&mbus->lock, flags);
1da177e4	118	return;
ecb658d3	119	}
1da177e4	120
ecb658d3 PZ	121	static void mon_submit_error(struct usb_bus ubus, struct urb urb, int error)
	122	{
	123	struct mon_bus *mbus;
	124
	125	if ((mbus = ubus->mon_bus) != NULL)
	126	mon_bus_submit_error(mbus, urb, error);
	127	mon_bus_submit_error(&mon_bus0, urb, error);
1da177e4 LT	128	}
	129
	130	/*
	131	*/
ecb658d3	132	static void mon_bus_complete(struct mon_bus mbus, struct urb urb)
1da177e4	133	{
1da177e4 LT	134	unsigned long flags;
	135	struct list_head *pos;
	136	struct mon_reader *r;
	137
ecb658d3 PZ	138	spin_lock_irqsave(&mbus->lock, flags);
	139	mbus->cnt_events++;
	140	list_for_each (pos, &mbus->r_list) {
	141	r = list_entry(pos, struct mon_reader, r_link);
	142	r->rnf_complete(r->r_data, urb);
	143	}
	144	spin_unlock_irqrestore(&mbus->lock, flags);
	145	}
	146
	147	static void mon_complete(struct usb_bus ubus, struct urb urb)
	148	{
	149	struct mon_bus *mbus;
	150
1da177e4 LT	151	mbus = ubus->mon_bus;
	152	if (mbus == NULL) {
	153	/*
	154	* This should not happen.
	155	* At this point we do not even know the bus number...
	156	*/
	157	printk(KERN_ERR TAG ": Null mon bus in URB, pipe 0x%x\n",
	158	urb->pipe);
	159	return;
	160	}
	161
ecb658d3 PZ	162	mon_bus_complete(mbus, urb);
ecb658d3 PZ	163	mon_bus_complete(&mon_bus0, urb);
1da177e4 LT	164	}
	165
	166	/* int (unlink_urb) (struct urb urb, int status); */
	167
	168	/*
	169	* Stop monitoring.
1da177e4 LT	170	*/
	171	static void mon_stop(struct mon_bus *mbus)
	172	{
	173	struct usb_bus *ubus = mbus->u_bus;
ecb658d3	174	struct list_head *p;
1da177e4	175
ecb658d3 PZ	176	if (mbus == &mon_bus0) {
	177	list_for_each (p, &mon_buses) {
	178	mbus = list_entry(p, struct mon_bus, bus_link);
	179	/*
	180	* We do not change nreaders here, so rely on mon_lock.
	181	*/
	182	if (mbus->nreaders == 0 && (ubus = mbus->u_bus) != NULL)
	183	ubus->monitored = 0;
	184	}
	185	} else {
	186	/*
	187	* A stop can be called for a dissolved mon_bus in case of
	188	* a reader staying across an rmmod foo_hcd, so test ->u_bus.
	189	*/
	190	if (mon_bus0.nreaders == 0 && (ubus = mbus->u_bus) != NULL) {
	191	ubus->monitored = 0;
	192	mb();
	193	}
1da177e4 LT	194	}
	195	}
	196
	197	/*
	198	* Add a USB bus (usually by a modprobe foo-hcd)
	199	*
	200	* This does not return an error code because the core cannot care less
	201	* if monitoring is not established.
	202	*/
	203	static void mon_bus_add(struct usb_bus *ubus)
	204	{
6f23ee1f	205	mon_bus_init(ubus);
ecb658d3 PZ	206	mutex_lock(&mon_lock);
	207	if (mon_bus0.nreaders != 0)
	208	ubus->monitored = 1;
	209	mutex_unlock(&mon_lock);
1da177e4 LT	210	}
	211
	212	/*
	213	* Remove a USB bus (either from rmmod foo-hcd or from a hot-remove event).
	214	*/
	215	static void mon_bus_remove(struct usb_bus *ubus)
	216	{
	217	struct mon_bus *mbus = ubus->mon_bus;
	218
4186ecf8	219	mutex_lock(&mon_lock);
1da177e4	220	list_del(&mbus->bus_link);
6f23ee1f PZ	221	if (mbus->text_inited)
6f23ee1f PZ	222	mon_text_del(mbus);
1da177e4 LT	223
	224	mon_dissolve(mbus, ubus);
	225	kref_put(&mbus->ref, mon_bus_drop);
4186ecf8	226	mutex_unlock(&mon_lock);
1da177e4 LT	227	}
1da177e4 LT	228
72adaa96 GKH	229	static int mon_notify(struct notifier_block *self, unsigned long action,
	230	void *dev)
	231	{
	232	switch (action) {
	233	case USB_BUS_ADD:
	234	mon_bus_add(dev);
	235	break;
	236	case USB_BUS_REMOVE:
	237	mon_bus_remove(dev);
	238	}
	239	return NOTIFY_OK;
	240	}
	241
	242	static struct notifier_block mon_nb = {
	243	.notifier_call = mon_notify,
	244	};
	245
1da177e4 LT	246	/*
	247	* Ops
	248	*/
	249	static struct usb_mon_operations mon_ops_0 = {
	250	.urb_submit = mon_submit,
	251	.urb_submit_error = mon_submit_error,
	252	.urb_complete = mon_complete,
1da177e4 LT	253	};
	254
	255	/*
	256	* Tear usb_bus and mon_bus apart.
	257	*/
	258	static void mon_dissolve(struct mon_bus mbus, struct usb_bus ubus)
	259	{
	260
1da177e4	261	if (ubus->monitored) {
1da177e4 LT	262	ubus->monitored = 0;
	263	mb();
	264	}
	265
	266	ubus->mon_bus = NULL;
	267	mbus->u_bus = NULL;
	268	mb();
ecb658d3 PZ	269
ecb658d3 PZ	270	/* We want synchronize_irq() here, but that needs an argument. */
1da177e4 LT	271	}
	272
	273	/*
	274	*/
	275	static void mon_bus_drop(struct kref *r)
	276	{
	277	struct mon_bus *mbus = container_of(r, struct mon_bus, ref);
	278	kfree(mbus);
	279	}
	280
	281	/*
	282	* Initialize a bus for us:
	283	* - allocate mon_bus
	284	* - refcount USB bus struct
	285	* - link
	286	*/
6f23ee1f	287	static void mon_bus_init(struct usb_bus *ubus)
1da177e4	288	{
1da177e4	289	struct mon_bus *mbus;
1da177e4	290
80b6ca48	291	if ((mbus = kzalloc(sizeof(struct mon_bus), GFP_KERNEL)) == NULL)
1da177e4	292	goto err_alloc;
1da177e4 LT	293	kref_init(&mbus->ref);
	294	spin_lock_init(&mbus->lock);
	295	INIT_LIST_HEAD(&mbus->r_list);
	296
	297	/*
17200583 AS	298	* We don't need to take a reference to ubus, because we receive
17200583 AS	299	* a notification if the bus is about to be removed.
1da177e4	300	*/
1da177e4 LT	301	mbus->u_bus = ubus;
	302	ubus->mon_bus = mbus;
	303
ecb658d3	304	mbus->text_inited = mon_text_add(mbus, ubus->busnum);
6f23ee1f	305	// mon_bin_add(...)
1da177e4	306
4186ecf8	307	mutex_lock(&mon_lock);
1da177e4	308	list_add_tail(&mbus->bus_link, &mon_buses);
4186ecf8	309	mutex_unlock(&mon_lock);
1da177e4 LT	310	return;
1da177e4 LT	311
1da177e4 LT	312	err_alloc:
	313	return;
	314	}
	315
ecb658d3 PZ	316	static void mon_bus0_init(void)
	317	{
	318	struct mon_bus *mbus = &mon_bus0;
	319
	320	kref_init(&mbus->ref);
	321	spin_lock_init(&mbus->lock);
	322	INIT_LIST_HEAD(&mbus->r_list);
	323
	324	mbus->text_inited = mon_text_add(mbus, 0);
	325	// mbus->bin_inited = mon_bin_add(mbus, 0);
	326	}
	327
6f23ee1f PZ	328	/*
	329	* Search a USB bus by number. Notice that USB bus numbers start from one,
	330	* which we may later use to identify "all" with zero.
	331	*
	332	* This function must be called with mon_lock held.
	333	*
	334	* This is obviously inefficient and may be revised in the future.
	335	*/
	336	struct mon_bus *mon_bus_lookup(unsigned int num)
	337	{
	338	struct list_head *p;
	339	struct mon_bus *mbus;
	340
ecb658d3 PZ	341	if (num == 0) {
	342	return &mon_bus0;
	343	}
6f23ee1f PZ	344	list_for_each (p, &mon_buses) {
	345	mbus = list_entry(p, struct mon_bus, bus_link);
	346	if (mbus->u_bus->busnum == num) {
	347	return mbus;
	348	}
	349	}
	350	return NULL;
	351	}
	352
1da177e4 LT	353	static int __init mon_init(void)
	354	{
	355	struct usb_bus *ubus;
6f23ee1f	356	int rc;
1da177e4	357
6f23ee1f PZ	358	if ((rc = mon_text_init()) != 0)
	359	goto err_text;
	360	if ((rc = mon_bin_init()) != 0)
	361	goto err_bin;
1da177e4	362
ecb658d3 PZ	363	mon_bus0_init();
ecb658d3 PZ	364
1da177e4 LT	365	if (usb_mon_register(&mon_ops_0) != 0) {
1da177e4 LT	366	printk(KERN_NOTICE TAG ": unable to register with the core\n");
6f23ee1f PZ	367	rc = -ENODEV;
6f23ee1f PZ	368	goto err_reg;
1da177e4 LT	369	}
	370	// MOD_INC_USE_COUNT(which_module?);
	371
72adaa96 GKH	372	usb_register_notify(&mon_nb);
72adaa96 GKH	373
4186ecf8	374	mutex_lock(&usb_bus_list_lock);
1da177e4	375	list_for_each_entry (ubus, &usb_bus_list, bus_list) {
6f23ee1f	376	mon_bus_init(ubus);
1da177e4	377	}
4186ecf8	378	mutex_unlock(&usb_bus_list_lock);
1da177e4	379	return 0;
6f23ee1f PZ	380
	381	err_reg:
	382	mon_bin_exit();
	383	err_bin:
	384	mon_text_exit();
	385	err_text:
	386	return rc;
1da177e4 LT	387	}
	388
	389	static void __exit mon_exit(void)
	390	{
	391	struct mon_bus *mbus;
	392	struct list_head *p;
	393
72adaa96	394	usb_unregister_notify(&mon_nb);
1da177e4 LT	395	usb_mon_deregister();
1da177e4 LT	396
4186ecf8	397	mutex_lock(&mon_lock);
ecb658d3	398
1da177e4 LT	399	while (!list_empty(&mon_buses)) {
	400	p = mon_buses.next;
	401	mbus = list_entry(p, struct mon_bus, bus_link);
	402	list_del(p);
	403
6f23ee1f PZ	404	if (mbus->text_inited)
6f23ee1f PZ	405	mon_text_del(mbus);
1da177e4 LT	406
	407	/*
	408	* This never happens, because the open/close paths in
	409	* file level maintain module use counters and so rmmod fails
	410	* before reaching here. However, better be safe...
	411	*/
	412	if (mbus->nreaders) {
	413	printk(KERN_ERR TAG
	414	": Outstanding opens (%d) on usb%d, leaking...\n",
	415	mbus->nreaders, mbus->u_bus->busnum);
	416	atomic_set(&mbus->ref.refcount, 2); /* Force leak */
	417	}
	418
	419	mon_dissolve(mbus, mbus->u_bus);
	420	kref_put(&mbus->ref, mon_bus_drop);
	421	}
ecb658d3 PZ	422
	423	mbus = &mon_bus0;
	424	if (mbus->text_inited)
	425	mon_text_del(mbus);
	426
4186ecf8	427	mutex_unlock(&mon_lock);
1da177e4	428
6f23ee1f PZ	429	mon_text_exit();
6f23ee1f PZ	430	mon_bin_exit();
1da177e4 LT	431	}
	432
	433	module_init(mon_init);
	434	module_exit(mon_exit);
	435
	436	MODULE_LICENSE("GPL");