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v4.6
  1/*
  2 * The USB Monitor, inspired by Dave Harding's USBMon.
  3 *
  4 * mon_main.c: Main file, module initiation and exit, registrations, etc.
  5 *
  6 * Copyright (C) 2005 Pete Zaitcev (zaitcev@redhat.com)
  7 */
  8
  9#include <linux/kernel.h>
 10#include <linux/module.h>
 11#include <linux/usb.h>
 12#include <linux/usb/hcd.h>
 13#include <linux/slab.h>
 14#include <linux/notifier.h>
 15#include <linux/mutex.h>
 16
 17#include "usb_mon.h"
 18
 19
 20static void mon_stop(struct mon_bus *mbus);
 21static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus);
 22static void mon_bus_drop(struct kref *r);
 23static void mon_bus_init(struct usb_bus *ubus);
 24
 25DEFINE_MUTEX(mon_lock);
 26
 27struct mon_bus mon_bus0;		/* Pseudo bus meaning "all buses" */
 28static LIST_HEAD(mon_buses);		/* All buses we know: struct mon_bus */
 29
 30/*
 31 * Link a reader into the bus.
 32 *
 33 * This must be called with mon_lock taken because of mbus->ref.
 34 */
 35void mon_reader_add(struct mon_bus *mbus, struct mon_reader *r)
 36{
 37	unsigned long flags;
 38	struct list_head *p;
 39
 40	spin_lock_irqsave(&mbus->lock, flags);
 41	if (mbus->nreaders == 0) {
 42		if (mbus == &mon_bus0) {
 43			list_for_each (p, &mon_buses) {
 44				struct mon_bus *m1;
 45				m1 = list_entry(p, struct mon_bus, bus_link);
 46				m1->u_bus->monitored = 1;
 47			}
 48		} else {
 49			mbus->u_bus->monitored = 1;
 50		}
 51	}
 52	mbus->nreaders++;
 53	list_add_tail(&r->r_link, &mbus->r_list);
 54	spin_unlock_irqrestore(&mbus->lock, flags);
 55
 56	kref_get(&mbus->ref);
 57}
 58
 59/*
 60 * Unlink reader from the bus.
 61 *
 62 * This is called with mon_lock taken, so we can decrement mbus->ref.
 63 */
 64void mon_reader_del(struct mon_bus *mbus, struct mon_reader *r)
 65{
 66	unsigned long flags;
 67
 68	spin_lock_irqsave(&mbus->lock, flags);
 69	list_del(&r->r_link);
 70	--mbus->nreaders;
 71	if (mbus->nreaders == 0)
 72		mon_stop(mbus);
 73	spin_unlock_irqrestore(&mbus->lock, flags);
 74
 75	kref_put(&mbus->ref, mon_bus_drop);
 76}
 77
 78/*
 79 */
 80static void mon_bus_submit(struct mon_bus *mbus, struct urb *urb)
 81{
 82	unsigned long flags;
 83	struct list_head *pos;
 84	struct mon_reader *r;
 85
 86	spin_lock_irqsave(&mbus->lock, flags);
 87	mbus->cnt_events++;
 88	list_for_each (pos, &mbus->r_list) {
 89		r = list_entry(pos, struct mon_reader, r_link);
 90		r->rnf_submit(r->r_data, urb);
 91	}
 92	spin_unlock_irqrestore(&mbus->lock, flags);
 93}
 94
 95static void mon_submit(struct usb_bus *ubus, struct urb *urb)
 96{
 97	struct mon_bus *mbus;
 98
 99	mbus = ubus->mon_bus;
100	if (mbus != NULL)
101		mon_bus_submit(mbus, urb);
102	mon_bus_submit(&mon_bus0, urb);
103}
104
105/*
106 */
107static void mon_bus_submit_error(struct mon_bus *mbus, struct urb *urb, int error)
108{
109	unsigned long flags;
110	struct list_head *pos;
111	struct mon_reader *r;
112
113	spin_lock_irqsave(&mbus->lock, flags);
114	mbus->cnt_events++;
115	list_for_each (pos, &mbus->r_list) {
116		r = list_entry(pos, struct mon_reader, r_link);
117		r->rnf_error(r->r_data, urb, error);
118	}
119	spin_unlock_irqrestore(&mbus->lock, flags);
120}
121
122static void mon_submit_error(struct usb_bus *ubus, struct urb *urb, int error)
123{
124	struct mon_bus *mbus;
125
126	mbus = ubus->mon_bus;
127	if (mbus != NULL)
128		mon_bus_submit_error(mbus, urb, error);
129	mon_bus_submit_error(&mon_bus0, urb, error);
130}
131
132/*
133 */
134static void mon_bus_complete(struct mon_bus *mbus, struct urb *urb, int status)
135{
136	unsigned long flags;
137	struct list_head *pos;
138	struct mon_reader *r;
139
140	spin_lock_irqsave(&mbus->lock, flags);
141	mbus->cnt_events++;
142	list_for_each (pos, &mbus->r_list) {
143		r = list_entry(pos, struct mon_reader, r_link);
144		r->rnf_complete(r->r_data, urb, status);
145	}
146	spin_unlock_irqrestore(&mbus->lock, flags);
147}
148
149static void mon_complete(struct usb_bus *ubus, struct urb *urb, int status)
150{
151	struct mon_bus *mbus;
152
153	mbus = ubus->mon_bus;
154	if (mbus != NULL)
155		mon_bus_complete(mbus, urb, status);
156	mon_bus_complete(&mon_bus0, urb, status);
157}
158
159/* int (*unlink_urb) (struct urb *urb, int status); */
160
161/*
162 * Stop monitoring.
163 */
164static void mon_stop(struct mon_bus *mbus)
165{
166	struct usb_bus *ubus;
167	struct list_head *p;
168
169	if (mbus == &mon_bus0) {
170		list_for_each (p, &mon_buses) {
171			mbus = list_entry(p, struct mon_bus, bus_link);
172			/*
173			 * We do not change nreaders here, so rely on mon_lock.
174			 */
175			if (mbus->nreaders == 0 && (ubus = mbus->u_bus) != NULL)
176				ubus->monitored = 0;
177		}
178	} else {
179		/*
180		 * A stop can be called for a dissolved mon_bus in case of
181		 * a reader staying across an rmmod foo_hcd, so test ->u_bus.
182		 */
183		if (mon_bus0.nreaders == 0 && (ubus = mbus->u_bus) != NULL) {
184			ubus->monitored = 0;
185			mb();
186		}
187	}
188}
189
190/*
191 * Add a USB bus (usually by a modprobe foo-hcd)
192 *
193 * This does not return an error code because the core cannot care less
194 * if monitoring is not established.
195 */
196static void mon_bus_add(struct usb_bus *ubus)
197{
198	mon_bus_init(ubus);
199	mutex_lock(&mon_lock);
200	if (mon_bus0.nreaders != 0)
201		ubus->monitored = 1;
202	mutex_unlock(&mon_lock);
203}
204
205/*
206 * Remove a USB bus (either from rmmod foo-hcd or from a hot-remove event).
207 */
208static void mon_bus_remove(struct usb_bus *ubus)
209{
210	struct mon_bus *mbus = ubus->mon_bus;
211
212	mutex_lock(&mon_lock);
213	list_del(&mbus->bus_link);
214	if (mbus->text_inited)
215		mon_text_del(mbus);
216	if (mbus->bin_inited)
217		mon_bin_del(mbus);
218
219	mon_dissolve(mbus, ubus);
220	kref_put(&mbus->ref, mon_bus_drop);
221	mutex_unlock(&mon_lock);
222}
223
224static int mon_notify(struct notifier_block *self, unsigned long action,
225		      void *dev)
226{
227	switch (action) {
228	case USB_BUS_ADD:
229		mon_bus_add(dev);
230		break;
231	case USB_BUS_REMOVE:
232		mon_bus_remove(dev);
233	}
234	return NOTIFY_OK;
235}
236
237static struct notifier_block mon_nb = {
238	.notifier_call = 	mon_notify,
239};
240
241/*
242 * Ops
243 */
244static const struct usb_mon_operations mon_ops_0 = {
245	.urb_submit =	mon_submit,
246	.urb_submit_error = mon_submit_error,
247	.urb_complete =	mon_complete,
248};
249
250/*
251 * Tear usb_bus and mon_bus apart.
252 */
253static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus)
254{
255
256	if (ubus->monitored) {
257		ubus->monitored = 0;
258		mb();
259	}
260
261	ubus->mon_bus = NULL;
262	mbus->u_bus = NULL;
263	mb();
264
265	/* We want synchronize_irq() here, but that needs an argument. */
266}
267
268/*
269 */
270static void mon_bus_drop(struct kref *r)
271{
272	struct mon_bus *mbus = container_of(r, struct mon_bus, ref);
273	kfree(mbus);
274}
275
276/*
277 * Initialize a bus for us:
278 *  - allocate mon_bus
279 *  - refcount USB bus struct
280 *  - link
281 */
282static void mon_bus_init(struct usb_bus *ubus)
283{
284	struct mon_bus *mbus;
285
286	mbus = kzalloc(sizeof(struct mon_bus), GFP_KERNEL);
287	if (mbus == NULL)
288		goto err_alloc;
289	kref_init(&mbus->ref);
290	spin_lock_init(&mbus->lock);
291	INIT_LIST_HEAD(&mbus->r_list);
292
293	/*
294	 * We don't need to take a reference to ubus, because we receive
295	 * a notification if the bus is about to be removed.
296	 */
297	mbus->u_bus = ubus;
298	ubus->mon_bus = mbus;
299
300	mbus->text_inited = mon_text_add(mbus, ubus);
301	mbus->bin_inited = mon_bin_add(mbus, ubus);
302
303	mutex_lock(&mon_lock);
304	list_add_tail(&mbus->bus_link, &mon_buses);
305	mutex_unlock(&mon_lock);
306	return;
307
308err_alloc:
309	return;
310}
311
312static void mon_bus0_init(void)
313{
314	struct mon_bus *mbus = &mon_bus0;
315
316	kref_init(&mbus->ref);
317	spin_lock_init(&mbus->lock);
318	INIT_LIST_HEAD(&mbus->r_list);
319
320	mbus->text_inited = mon_text_add(mbus, NULL);
321	mbus->bin_inited = mon_bin_add(mbus, NULL);
322}
323
324/*
325 * Search a USB bus by number. Notice that USB bus numbers start from one,
326 * which we may later use to identify "all" with zero.
327 *
328 * This function must be called with mon_lock held.
329 *
330 * This is obviously inefficient and may be revised in the future.
331 */
332struct mon_bus *mon_bus_lookup(unsigned int num)
333{
334	struct list_head *p;
335	struct mon_bus *mbus;
336
337	if (num == 0) {
338		return &mon_bus0;
339	}
340	list_for_each (p, &mon_buses) {
341		mbus = list_entry(p, struct mon_bus, bus_link);
342		if (mbus->u_bus->busnum == num) {
343			return mbus;
344		}
345	}
346	return NULL;
347}
348
349static int __init mon_init(void)
350{
351	struct usb_bus *ubus;
352	int rc, id;
353
354	if ((rc = mon_text_init()) != 0)
355		goto err_text;
356	if ((rc = mon_bin_init()) != 0)
357		goto err_bin;
358
359	mon_bus0_init();
360
361	if (usb_mon_register(&mon_ops_0) != 0) {
362		printk(KERN_NOTICE TAG ": unable to register with the core\n");
363		rc = -ENODEV;
364		goto err_reg;
365	}
366	// MOD_INC_USE_COUNT(which_module?);
367
368	mutex_lock(&usb_bus_idr_lock);
369	idr_for_each_entry(&usb_bus_idr, ubus, id)
370		mon_bus_init(ubus);
371	usb_register_notify(&mon_nb);
372	mutex_unlock(&usb_bus_idr_lock);
373	return 0;
374
375err_reg:
376	mon_bin_exit();
377err_bin:
378	mon_text_exit();
379err_text:
380	return rc;
381}
382
383static void __exit mon_exit(void)
384{
385	struct mon_bus *mbus;
386	struct list_head *p;
387
388	usb_unregister_notify(&mon_nb);
389	usb_mon_deregister();
390
391	mutex_lock(&mon_lock);
392
393	while (!list_empty(&mon_buses)) {
394		p = mon_buses.next;
395		mbus = list_entry(p, struct mon_bus, bus_link);
396		list_del(p);
397
398		if (mbus->text_inited)
399			mon_text_del(mbus);
400		if (mbus->bin_inited)
401			mon_bin_del(mbus);
402
403		/*
404		 * This never happens, because the open/close paths in
405		 * file level maintain module use counters and so rmmod fails
406		 * before reaching here. However, better be safe...
407		 */
408		if (mbus->nreaders) {
409			printk(KERN_ERR TAG
410			    ": Outstanding opens (%d) on usb%d, leaking...\n",
411			    mbus->nreaders, mbus->u_bus->busnum);
412			atomic_set(&mbus->ref.refcount, 2);	/* Force leak */
413		}
414
415		mon_dissolve(mbus, mbus->u_bus);
416		kref_put(&mbus->ref, mon_bus_drop);
417	}
418
419	mbus = &mon_bus0;
420	if (mbus->text_inited)
421		mon_text_del(mbus);
422	if (mbus->bin_inited)
423		mon_bin_del(mbus);
424
425	mutex_unlock(&mon_lock);
426
427	mon_text_exit();
428	mon_bin_exit();
429}
430
431module_init(mon_init);
432module_exit(mon_exit);
433
434MODULE_LICENSE("GPL");
v4.10.11
  1/*
  2 * The USB Monitor, inspired by Dave Harding's USBMon.
  3 *
  4 * mon_main.c: Main file, module initiation and exit, registrations, etc.
  5 *
  6 * Copyright (C) 2005 Pete Zaitcev (zaitcev@redhat.com)
  7 */
  8
  9#include <linux/kernel.h>
 10#include <linux/module.h>
 11#include <linux/usb.h>
 12#include <linux/usb/hcd.h>
 13#include <linux/slab.h>
 14#include <linux/notifier.h>
 15#include <linux/mutex.h>
 16
 17#include "usb_mon.h"
 18
 19
 20static void mon_stop(struct mon_bus *mbus);
 21static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus);
 22static void mon_bus_drop(struct kref *r);
 23static void mon_bus_init(struct usb_bus *ubus);
 24
 25DEFINE_MUTEX(mon_lock);
 26
 27struct mon_bus mon_bus0;		/* Pseudo bus meaning "all buses" */
 28static LIST_HEAD(mon_buses);		/* All buses we know: struct mon_bus */
 29
 30/*
 31 * Link a reader into the bus.
 32 *
 33 * This must be called with mon_lock taken because of mbus->ref.
 34 */
 35void mon_reader_add(struct mon_bus *mbus, struct mon_reader *r)
 36{
 37	unsigned long flags;
 38	struct list_head *p;
 39
 40	spin_lock_irqsave(&mbus->lock, flags);
 41	if (mbus->nreaders == 0) {
 42		if (mbus == &mon_bus0) {
 43			list_for_each (p, &mon_buses) {
 44				struct mon_bus *m1;
 45				m1 = list_entry(p, struct mon_bus, bus_link);
 46				m1->u_bus->monitored = 1;
 47			}
 48		} else {
 49			mbus->u_bus->monitored = 1;
 50		}
 51	}
 52	mbus->nreaders++;
 53	list_add_tail(&r->r_link, &mbus->r_list);
 54	spin_unlock_irqrestore(&mbus->lock, flags);
 55
 56	kref_get(&mbus->ref);
 57}
 58
 59/*
 60 * Unlink reader from the bus.
 61 *
 62 * This is called with mon_lock taken, so we can decrement mbus->ref.
 63 */
 64void mon_reader_del(struct mon_bus *mbus, struct mon_reader *r)
 65{
 66	unsigned long flags;
 67
 68	spin_lock_irqsave(&mbus->lock, flags);
 69	list_del(&r->r_link);
 70	--mbus->nreaders;
 71	if (mbus->nreaders == 0)
 72		mon_stop(mbus);
 73	spin_unlock_irqrestore(&mbus->lock, flags);
 74
 75	kref_put(&mbus->ref, mon_bus_drop);
 76}
 77
 78/*
 79 */
 80static void mon_bus_submit(struct mon_bus *mbus, struct urb *urb)
 81{
 82	unsigned long flags;
 83	struct list_head *pos;
 84	struct mon_reader *r;
 85
 86	spin_lock_irqsave(&mbus->lock, flags);
 87	mbus->cnt_events++;
 88	list_for_each (pos, &mbus->r_list) {
 89		r = list_entry(pos, struct mon_reader, r_link);
 90		r->rnf_submit(r->r_data, urb);
 91	}
 92	spin_unlock_irqrestore(&mbus->lock, flags);
 93}
 94
 95static void mon_submit(struct usb_bus *ubus, struct urb *urb)
 96{
 97	struct mon_bus *mbus;
 98
 99	mbus = ubus->mon_bus;
100	if (mbus != NULL)
101		mon_bus_submit(mbus, urb);
102	mon_bus_submit(&mon_bus0, urb);
103}
104
105/*
106 */
107static void mon_bus_submit_error(struct mon_bus *mbus, struct urb *urb, int error)
108{
109	unsigned long flags;
110	struct list_head *pos;
111	struct mon_reader *r;
112
113	spin_lock_irqsave(&mbus->lock, flags);
114	mbus->cnt_events++;
115	list_for_each (pos, &mbus->r_list) {
116		r = list_entry(pos, struct mon_reader, r_link);
117		r->rnf_error(r->r_data, urb, error);
118	}
119	spin_unlock_irqrestore(&mbus->lock, flags);
120}
121
122static void mon_submit_error(struct usb_bus *ubus, struct urb *urb, int error)
123{
124	struct mon_bus *mbus;
125
126	mbus = ubus->mon_bus;
127	if (mbus != NULL)
128		mon_bus_submit_error(mbus, urb, error);
129	mon_bus_submit_error(&mon_bus0, urb, error);
130}
131
132/*
133 */
134static void mon_bus_complete(struct mon_bus *mbus, struct urb *urb, int status)
135{
136	unsigned long flags;
137	struct list_head *pos;
138	struct mon_reader *r;
139
140	spin_lock_irqsave(&mbus->lock, flags);
141	mbus->cnt_events++;
142	list_for_each (pos, &mbus->r_list) {
143		r = list_entry(pos, struct mon_reader, r_link);
144		r->rnf_complete(r->r_data, urb, status);
145	}
146	spin_unlock_irqrestore(&mbus->lock, flags);
147}
148
149static void mon_complete(struct usb_bus *ubus, struct urb *urb, int status)
150{
151	struct mon_bus *mbus;
152
153	mbus = ubus->mon_bus;
154	if (mbus != NULL)
155		mon_bus_complete(mbus, urb, status);
156	mon_bus_complete(&mon_bus0, urb, status);
157}
158
159/* int (*unlink_urb) (struct urb *urb, int status); */
160
161/*
162 * Stop monitoring.
163 */
164static void mon_stop(struct mon_bus *mbus)
165{
166	struct usb_bus *ubus;
167	struct list_head *p;
168
169	if (mbus == &mon_bus0) {
170		list_for_each (p, &mon_buses) {
171			mbus = list_entry(p, struct mon_bus, bus_link);
172			/*
173			 * We do not change nreaders here, so rely on mon_lock.
174			 */
175			if (mbus->nreaders == 0 && (ubus = mbus->u_bus) != NULL)
176				ubus->monitored = 0;
177		}
178	} else {
179		/*
180		 * A stop can be called for a dissolved mon_bus in case of
181		 * a reader staying across an rmmod foo_hcd, so test ->u_bus.
182		 */
183		if (mon_bus0.nreaders == 0 && (ubus = mbus->u_bus) != NULL) {
184			ubus->monitored = 0;
185			mb();
186		}
187	}
188}
189
190/*
191 * Add a USB bus (usually by a modprobe foo-hcd)
192 *
193 * This does not return an error code because the core cannot care less
194 * if monitoring is not established.
195 */
196static void mon_bus_add(struct usb_bus *ubus)
197{
198	mon_bus_init(ubus);
199	mutex_lock(&mon_lock);
200	if (mon_bus0.nreaders != 0)
201		ubus->monitored = 1;
202	mutex_unlock(&mon_lock);
203}
204
205/*
206 * Remove a USB bus (either from rmmod foo-hcd or from a hot-remove event).
207 */
208static void mon_bus_remove(struct usb_bus *ubus)
209{
210	struct mon_bus *mbus = ubus->mon_bus;
211
212	mutex_lock(&mon_lock);
213	list_del(&mbus->bus_link);
214	if (mbus->text_inited)
215		mon_text_del(mbus);
216	if (mbus->bin_inited)
217		mon_bin_del(mbus);
218
219	mon_dissolve(mbus, ubus);
220	kref_put(&mbus->ref, mon_bus_drop);
221	mutex_unlock(&mon_lock);
222}
223
224static int mon_notify(struct notifier_block *self, unsigned long action,
225		      void *dev)
226{
227	switch (action) {
228	case USB_BUS_ADD:
229		mon_bus_add(dev);
230		break;
231	case USB_BUS_REMOVE:
232		mon_bus_remove(dev);
233	}
234	return NOTIFY_OK;
235}
236
237static struct notifier_block mon_nb = {
238	.notifier_call = 	mon_notify,
239};
240
241/*
242 * Ops
243 */
244static const struct usb_mon_operations mon_ops_0 = {
245	.urb_submit =	mon_submit,
246	.urb_submit_error = mon_submit_error,
247	.urb_complete =	mon_complete,
248};
249
250/*
251 * Tear usb_bus and mon_bus apart.
252 */
253static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus)
254{
255
256	if (ubus->monitored) {
257		ubus->monitored = 0;
258		mb();
259	}
260
261	ubus->mon_bus = NULL;
262	mbus->u_bus = NULL;
263	mb();
264
265	/* We want synchronize_irq() here, but that needs an argument. */
266}
267
268/*
269 */
270static void mon_bus_drop(struct kref *r)
271{
272	struct mon_bus *mbus = container_of(r, struct mon_bus, ref);
273	kfree(mbus);
274}
275
276/*
277 * Initialize a bus for us:
278 *  - allocate mon_bus
279 *  - refcount USB bus struct
280 *  - link
281 */
282static void mon_bus_init(struct usb_bus *ubus)
283{
284	struct mon_bus *mbus;
285
286	mbus = kzalloc(sizeof(struct mon_bus), GFP_KERNEL);
287	if (mbus == NULL)
288		goto err_alloc;
289	kref_init(&mbus->ref);
290	spin_lock_init(&mbus->lock);
291	INIT_LIST_HEAD(&mbus->r_list);
292
293	/*
294	 * We don't need to take a reference to ubus, because we receive
295	 * a notification if the bus is about to be removed.
296	 */
297	mbus->u_bus = ubus;
298	ubus->mon_bus = mbus;
299
300	mbus->text_inited = mon_text_add(mbus, ubus);
301	mbus->bin_inited = mon_bin_add(mbus, ubus);
302
303	mutex_lock(&mon_lock);
304	list_add_tail(&mbus->bus_link, &mon_buses);
305	mutex_unlock(&mon_lock);
306	return;
307
308err_alloc:
309	return;
310}
311
312static void mon_bus0_init(void)
313{
314	struct mon_bus *mbus = &mon_bus0;
315
316	kref_init(&mbus->ref);
317	spin_lock_init(&mbus->lock);
318	INIT_LIST_HEAD(&mbus->r_list);
319
320	mbus->text_inited = mon_text_add(mbus, NULL);
321	mbus->bin_inited = mon_bin_add(mbus, NULL);
322}
323
324/*
325 * Search a USB bus by number. Notice that USB bus numbers start from one,
326 * which we may later use to identify "all" with zero.
327 *
328 * This function must be called with mon_lock held.
329 *
330 * This is obviously inefficient and may be revised in the future.
331 */
332struct mon_bus *mon_bus_lookup(unsigned int num)
333{
334	struct list_head *p;
335	struct mon_bus *mbus;
336
337	if (num == 0) {
338		return &mon_bus0;
339	}
340	list_for_each (p, &mon_buses) {
341		mbus = list_entry(p, struct mon_bus, bus_link);
342		if (mbus->u_bus->busnum == num) {
343			return mbus;
344		}
345	}
346	return NULL;
347}
348
349static int __init mon_init(void)
350{
351	struct usb_bus *ubus;
352	int rc, id;
353
354	if ((rc = mon_text_init()) != 0)
355		goto err_text;
356	if ((rc = mon_bin_init()) != 0)
357		goto err_bin;
358
359	mon_bus0_init();
360
361	if (usb_mon_register(&mon_ops_0) != 0) {
362		printk(KERN_NOTICE TAG ": unable to register with the core\n");
363		rc = -ENODEV;
364		goto err_reg;
365	}
366	// MOD_INC_USE_COUNT(which_module?);
367
368	mutex_lock(&usb_bus_idr_lock);
369	idr_for_each_entry(&usb_bus_idr, ubus, id)
370		mon_bus_init(ubus);
371	usb_register_notify(&mon_nb);
372	mutex_unlock(&usb_bus_idr_lock);
373	return 0;
374
375err_reg:
376	mon_bin_exit();
377err_bin:
378	mon_text_exit();
379err_text:
380	return rc;
381}
382
383static void __exit mon_exit(void)
384{
385	struct mon_bus *mbus;
386	struct list_head *p;
387
388	usb_unregister_notify(&mon_nb);
389	usb_mon_deregister();
390
391	mutex_lock(&mon_lock);
392
393	while (!list_empty(&mon_buses)) {
394		p = mon_buses.next;
395		mbus = list_entry(p, struct mon_bus, bus_link);
396		list_del(p);
397
398		if (mbus->text_inited)
399			mon_text_del(mbus);
400		if (mbus->bin_inited)
401			mon_bin_del(mbus);
402
403		/*
404		 * This never happens, because the open/close paths in
405		 * file level maintain module use counters and so rmmod fails
406		 * before reaching here. However, better be safe...
407		 */
408		if (mbus->nreaders) {
409			printk(KERN_ERR TAG
410			    ": Outstanding opens (%d) on usb%d, leaking...\n",
411			    mbus->nreaders, mbus->u_bus->busnum);
412			atomic_set(&mbus->ref.refcount, 2);	/* Force leak */
413		}
414
415		mon_dissolve(mbus, mbus->u_bus);
416		kref_put(&mbus->ref, mon_bus_drop);
417	}
418
419	mbus = &mon_bus0;
420	if (mbus->text_inited)
421		mon_text_del(mbus);
422	if (mbus->bin_inited)
423		mon_bin_del(mbus);
424
425	mutex_unlock(&mon_lock);
426
427	mon_text_exit();
428	mon_bin_exit();
429}
430
431module_init(mon_init);
432module_exit(mon_exit);
433
434MODULE_LICENSE("GPL");