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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * The USB Monitor, inspired by Dave Harding's USBMon.
4 *
5 * mon_main.c: Main file, module initiation and exit, registrations, etc.
6 *
7 * Copyright (C) 2005 Pete Zaitcev (zaitcev@redhat.com)
8 */
9
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/usb.h>
13#include <linux/usb/hcd.h>
14#include <linux/slab.h>
15#include <linux/notifier.h>
16#include <linux/mutex.h>
17
18#include "usb_mon.h"
19
20
21static void mon_stop(struct mon_bus *mbus);
22static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus);
23static void mon_bus_drop(struct kref *r);
24static void mon_bus_init(struct usb_bus *ubus);
25
26DEFINE_MUTEX(mon_lock);
27
28struct mon_bus mon_bus0; /* Pseudo bus meaning "all buses" */
29static LIST_HEAD(mon_buses); /* All buses we know: struct mon_bus */
30
31/*
32 * Link a reader into the bus.
33 *
34 * This must be called with mon_lock taken because of mbus->ref.
35 */
36void mon_reader_add(struct mon_bus *mbus, struct mon_reader *r)
37{
38 unsigned long flags;
39 struct list_head *p;
40
41 spin_lock_irqsave(&mbus->lock, flags);
42 if (mbus->nreaders == 0) {
43 if (mbus == &mon_bus0) {
44 list_for_each (p, &mon_buses) {
45 struct mon_bus *m1;
46 m1 = list_entry(p, struct mon_bus, bus_link);
47 m1->u_bus->monitored = 1;
48 }
49 } else {
50 mbus->u_bus->monitored = 1;
51 }
52 }
53 mbus->nreaders++;
54 list_add_tail(&r->r_link, &mbus->r_list);
55 spin_unlock_irqrestore(&mbus->lock, flags);
56
57 kref_get(&mbus->ref);
58}
59
60/*
61 * Unlink reader from the bus.
62 *
63 * This is called with mon_lock taken, so we can decrement mbus->ref.
64 */
65void mon_reader_del(struct mon_bus *mbus, struct mon_reader *r)
66{
67 unsigned long flags;
68
69 spin_lock_irqsave(&mbus->lock, flags);
70 list_del(&r->r_link);
71 --mbus->nreaders;
72 if (mbus->nreaders == 0)
73 mon_stop(mbus);
74 spin_unlock_irqrestore(&mbus->lock, flags);
75
76 kref_put(&mbus->ref, mon_bus_drop);
77}
78
79/*
80 */
81static void mon_bus_submit(struct mon_bus *mbus, struct urb *urb)
82{
83 unsigned long flags;
84 struct list_head *pos;
85 struct mon_reader *r;
86
87 spin_lock_irqsave(&mbus->lock, flags);
88 mbus->cnt_events++;
89 list_for_each (pos, &mbus->r_list) {
90 r = list_entry(pos, struct mon_reader, r_link);
91 r->rnf_submit(r->r_data, urb);
92 }
93 spin_unlock_irqrestore(&mbus->lock, flags);
94}
95
96static void mon_submit(struct usb_bus *ubus, struct urb *urb)
97{
98 struct mon_bus *mbus;
99
100 mbus = ubus->mon_bus;
101 if (mbus != NULL)
102 mon_bus_submit(mbus, urb);
103 mon_bus_submit(&mon_bus0, urb);
104}
105
106/*
107 */
108static void mon_bus_submit_error(struct mon_bus *mbus, struct urb *urb, int error)
109{
110 unsigned long flags;
111 struct list_head *pos;
112 struct mon_reader *r;
113
114 spin_lock_irqsave(&mbus->lock, flags);
115 mbus->cnt_events++;
116 list_for_each (pos, &mbus->r_list) {
117 r = list_entry(pos, struct mon_reader, r_link);
118 r->rnf_error(r->r_data, urb, error);
119 }
120 spin_unlock_irqrestore(&mbus->lock, flags);
121}
122
123static void mon_submit_error(struct usb_bus *ubus, struct urb *urb, int error)
124{
125 struct mon_bus *mbus;
126
127 mbus = ubus->mon_bus;
128 if (mbus != NULL)
129 mon_bus_submit_error(mbus, urb, error);
130 mon_bus_submit_error(&mon_bus0, urb, error);
131}
132
133/*
134 */
135static void mon_bus_complete(struct mon_bus *mbus, struct urb *urb, int status)
136{
137 unsigned long flags;
138 struct list_head *pos;
139 struct mon_reader *r;
140
141 spin_lock_irqsave(&mbus->lock, flags);
142 mbus->cnt_events++;
143 list_for_each (pos, &mbus->r_list) {
144 r = list_entry(pos, struct mon_reader, r_link);
145 r->rnf_complete(r->r_data, urb, status);
146 }
147 spin_unlock_irqrestore(&mbus->lock, flags);
148}
149
150static void mon_complete(struct usb_bus *ubus, struct urb *urb, int status)
151{
152 struct mon_bus *mbus;
153
154 mbus = ubus->mon_bus;
155 if (mbus != NULL)
156 mon_bus_complete(mbus, urb, status);
157 mon_bus_complete(&mon_bus0, urb, status);
158}
159
160/* int (*unlink_urb) (struct urb *urb, int status); */
161
162/*
163 * Stop monitoring.
164 */
165static void mon_stop(struct mon_bus *mbus)
166{
167 struct usb_bus *ubus;
168 struct list_head *p;
169
170 if (mbus == &mon_bus0) {
171 list_for_each (p, &mon_buses) {
172 mbus = list_entry(p, struct mon_bus, bus_link);
173 /*
174 * We do not change nreaders here, so rely on mon_lock.
175 */
176 if (mbus->nreaders == 0 && (ubus = mbus->u_bus) != NULL)
177 ubus->monitored = 0;
178 }
179 } else {
180 /*
181 * A stop can be called for a dissolved mon_bus in case of
182 * a reader staying across an rmmod foo_hcd, so test ->u_bus.
183 */
184 if (mon_bus0.nreaders == 0 && (ubus = mbus->u_bus) != NULL) {
185 ubus->monitored = 0;
186 mb();
187 }
188 }
189}
190
191/*
192 * Add a USB bus (usually by a modprobe foo-hcd)
193 *
194 * This does not return an error code because the core cannot care less
195 * if monitoring is not established.
196 */
197static void mon_bus_add(struct usb_bus *ubus)
198{
199 mon_bus_init(ubus);
200 mutex_lock(&mon_lock);
201 if (mon_bus0.nreaders != 0)
202 ubus->monitored = 1;
203 mutex_unlock(&mon_lock);
204}
205
206/*
207 * Remove a USB bus (either from rmmod foo-hcd or from a hot-remove event).
208 */
209static void mon_bus_remove(struct usb_bus *ubus)
210{
211 struct mon_bus *mbus = ubus->mon_bus;
212
213 mutex_lock(&mon_lock);
214 list_del(&mbus->bus_link);
215 if (mbus->text_inited)
216 mon_text_del(mbus);
217 if (mbus->bin_inited)
218 mon_bin_del(mbus);
219
220 mon_dissolve(mbus, ubus);
221 kref_put(&mbus->ref, mon_bus_drop);
222 mutex_unlock(&mon_lock);
223}
224
225static int mon_notify(struct notifier_block *self, unsigned long action,
226 void *dev)
227{
228 switch (action) {
229 case USB_BUS_ADD:
230 mon_bus_add(dev);
231 break;
232 case USB_BUS_REMOVE:
233 mon_bus_remove(dev);
234 }
235 return NOTIFY_OK;
236}
237
238static struct notifier_block mon_nb = {
239 .notifier_call = mon_notify,
240};
241
242/*
243 * Ops
244 */
245static const struct usb_mon_operations mon_ops_0 = {
246 .urb_submit = mon_submit,
247 .urb_submit_error = mon_submit_error,
248 .urb_complete = mon_complete,
249};
250
251/*
252 * Tear usb_bus and mon_bus apart.
253 */
254static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus)
255{
256
257 if (ubus->monitored) {
258 ubus->monitored = 0;
259 mb();
260 }
261
262 ubus->mon_bus = NULL;
263 mbus->u_bus = NULL;
264 mb();
265
266 /* We want synchronize_irq() here, but that needs an argument. */
267}
268
269/*
270 */
271static void mon_bus_drop(struct kref *r)
272{
273 struct mon_bus *mbus = container_of(r, struct mon_bus, ref);
274 kfree(mbus);
275}
276
277/*
278 * Initialize a bus for us:
279 * - allocate mon_bus
280 * - refcount USB bus struct
281 * - link
282 */
283static void mon_bus_init(struct usb_bus *ubus)
284{
285 struct mon_bus *mbus;
286
287 mbus = kzalloc(sizeof(struct mon_bus), GFP_KERNEL);
288 if (mbus == NULL)
289 goto err_alloc;
290 kref_init(&mbus->ref);
291 spin_lock_init(&mbus->lock);
292 INIT_LIST_HEAD(&mbus->r_list);
293
294 /*
295 * We don't need to take a reference to ubus, because we receive
296 * a notification if the bus is about to be removed.
297 */
298 mbus->u_bus = ubus;
299 ubus->mon_bus = mbus;
300
301 mbus->text_inited = mon_text_add(mbus, ubus);
302 mbus->bin_inited = mon_bin_add(mbus, ubus);
303
304 mutex_lock(&mon_lock);
305 list_add_tail(&mbus->bus_link, &mon_buses);
306 mutex_unlock(&mon_lock);
307 return;
308
309err_alloc:
310 return;
311}
312
313static void mon_bus0_init(void)
314{
315 struct mon_bus *mbus = &mon_bus0;
316
317 kref_init(&mbus->ref);
318 spin_lock_init(&mbus->lock);
319 INIT_LIST_HEAD(&mbus->r_list);
320
321 mbus->text_inited = mon_text_add(mbus, NULL);
322 mbus->bin_inited = mon_bin_add(mbus, NULL);
323}
324
325/*
326 * Search a USB bus by number. Notice that USB bus numbers start from one,
327 * which we may later use to identify "all" with zero.
328 *
329 * This function must be called with mon_lock held.
330 *
331 * This is obviously inefficient and may be revised in the future.
332 */
333struct mon_bus *mon_bus_lookup(unsigned int num)
334{
335 struct list_head *p;
336 struct mon_bus *mbus;
337
338 if (num == 0) {
339 return &mon_bus0;
340 }
341 list_for_each (p, &mon_buses) {
342 mbus = list_entry(p, struct mon_bus, bus_link);
343 if (mbus->u_bus->busnum == num) {
344 return mbus;
345 }
346 }
347 return NULL;
348}
349
350static int __init mon_init(void)
351{
352 struct usb_bus *ubus;
353 int rc, id;
354
355 if ((rc = mon_text_init()) != 0)
356 goto err_text;
357 if ((rc = mon_bin_init()) != 0)
358 goto err_bin;
359
360 mon_bus0_init();
361
362 if (usb_mon_register(&mon_ops_0) != 0) {
363 printk(KERN_NOTICE TAG ": unable to register with the core\n");
364 rc = -ENODEV;
365 goto err_reg;
366 }
367 // MOD_INC_USE_COUNT(which_module?);
368
369 mutex_lock(&usb_bus_idr_lock);
370 idr_for_each_entry(&usb_bus_idr, ubus, id)
371 mon_bus_init(ubus);
372 usb_register_notify(&mon_nb);
373 mutex_unlock(&usb_bus_idr_lock);
374 return 0;
375
376err_reg:
377 mon_bin_exit();
378err_bin:
379 mon_text_exit();
380err_text:
381 return rc;
382}
383
384static void __exit mon_exit(void)
385{
386 struct mon_bus *mbus;
387 struct list_head *p;
388
389 usb_unregister_notify(&mon_nb);
390 usb_mon_deregister();
391
392 mutex_lock(&mon_lock);
393
394 while (!list_empty(&mon_buses)) {
395 p = mon_buses.next;
396 mbus = list_entry(p, struct mon_bus, bus_link);
397 list_del(p);
398
399 if (mbus->text_inited)
400 mon_text_del(mbus);
401 if (mbus->bin_inited)
402 mon_bin_del(mbus);
403
404 /*
405 * This never happens, because the open/close paths in
406 * file level maintain module use counters and so rmmod fails
407 * before reaching here. However, better be safe...
408 */
409 if (mbus->nreaders) {
410 printk(KERN_ERR TAG
411 ": Outstanding opens (%d) on usb%d, leaking...\n",
412 mbus->nreaders, mbus->u_bus->busnum);
413 kref_get(&mbus->ref); /* Force leak */
414 }
415
416 mon_dissolve(mbus, mbus->u_bus);
417 kref_put(&mbus->ref, mon_bus_drop);
418 }
419
420 mbus = &mon_bus0;
421 if (mbus->text_inited)
422 mon_text_del(mbus);
423 if (mbus->bin_inited)
424 mon_bin_del(mbus);
425
426 mutex_unlock(&mon_lock);
427
428 mon_text_exit();
429 mon_bin_exit();
430}
431
432module_init(mon_init);
433module_exit(mon_exit);
434
435MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * The USB Monitor, inspired by Dave Harding's USBMon.
4 *
5 * mon_main.c: Main file, module initiation and exit, registrations, etc.
6 *
7 * Copyright (C) 2005 Pete Zaitcev (zaitcev@redhat.com)
8 */
9
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/usb.h>
13#include <linux/usb/hcd.h>
14#include <linux/slab.h>
15#include <linux/notifier.h>
16#include <linux/mutex.h>
17
18#include "usb_mon.h"
19
20
21static void mon_stop(struct mon_bus *mbus);
22static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus);
23static void mon_bus_drop(struct kref *r);
24static void mon_bus_init(struct usb_bus *ubus);
25
26DEFINE_MUTEX(mon_lock);
27
28struct mon_bus mon_bus0; /* Pseudo bus meaning "all buses" */
29static LIST_HEAD(mon_buses); /* All buses we know: struct mon_bus */
30
31/*
32 * Link a reader into the bus.
33 *
34 * This must be called with mon_lock taken because of mbus->ref.
35 */
36void mon_reader_add(struct mon_bus *mbus, struct mon_reader *r)
37{
38 unsigned long flags;
39 struct list_head *p;
40
41 spin_lock_irqsave(&mbus->lock, flags);
42 if (mbus->nreaders == 0) {
43 if (mbus == &mon_bus0) {
44 list_for_each (p, &mon_buses) {
45 struct mon_bus *m1;
46 m1 = list_entry(p, struct mon_bus, bus_link);
47 m1->u_bus->monitored = 1;
48 }
49 } else {
50 mbus->u_bus->monitored = 1;
51 }
52 }
53 mbus->nreaders++;
54 list_add_tail(&r->r_link, &mbus->r_list);
55 spin_unlock_irqrestore(&mbus->lock, flags);
56
57 kref_get(&mbus->ref);
58}
59
60/*
61 * Unlink reader from the bus.
62 *
63 * This is called with mon_lock taken, so we can decrement mbus->ref.
64 */
65void mon_reader_del(struct mon_bus *mbus, struct mon_reader *r)
66{
67 unsigned long flags;
68
69 spin_lock_irqsave(&mbus->lock, flags);
70 list_del(&r->r_link);
71 --mbus->nreaders;
72 if (mbus->nreaders == 0)
73 mon_stop(mbus);
74 spin_unlock_irqrestore(&mbus->lock, flags);
75
76 kref_put(&mbus->ref, mon_bus_drop);
77}
78
79/*
80 */
81static void mon_bus_submit(struct mon_bus *mbus, struct urb *urb)
82{
83 unsigned long flags;
84 struct mon_reader *r;
85
86 spin_lock_irqsave(&mbus->lock, flags);
87 mbus->cnt_events++;
88 list_for_each_entry(r, &mbus->r_list, r_link)
89 r->rnf_submit(r->r_data, urb);
90 spin_unlock_irqrestore(&mbus->lock, flags);
91}
92
93static void mon_submit(struct usb_bus *ubus, struct urb *urb)
94{
95 struct mon_bus *mbus;
96
97 mbus = ubus->mon_bus;
98 if (mbus != NULL)
99 mon_bus_submit(mbus, urb);
100 mon_bus_submit(&mon_bus0, urb);
101}
102
103/*
104 */
105static void mon_bus_submit_error(struct mon_bus *mbus, struct urb *urb, int error)
106{
107 unsigned long flags;
108 struct mon_reader *r;
109
110 spin_lock_irqsave(&mbus->lock, flags);
111 mbus->cnt_events++;
112 list_for_each_entry(r, &mbus->r_list, r_link)
113 r->rnf_error(r->r_data, urb, error);
114 spin_unlock_irqrestore(&mbus->lock, flags);
115}
116
117static void mon_submit_error(struct usb_bus *ubus, struct urb *urb, int error)
118{
119 struct mon_bus *mbus;
120
121 mbus = ubus->mon_bus;
122 if (mbus != NULL)
123 mon_bus_submit_error(mbus, urb, error);
124 mon_bus_submit_error(&mon_bus0, urb, error);
125}
126
127/*
128 */
129static void mon_bus_complete(struct mon_bus *mbus, struct urb *urb, int status)
130{
131 unsigned long flags;
132 struct mon_reader *r;
133
134 spin_lock_irqsave(&mbus->lock, flags);
135 mbus->cnt_events++;
136 list_for_each_entry(r, &mbus->r_list, r_link)
137 r->rnf_complete(r->r_data, urb, status);
138 spin_unlock_irqrestore(&mbus->lock, flags);
139}
140
141static void mon_complete(struct usb_bus *ubus, struct urb *urb, int status)
142{
143 struct mon_bus *mbus;
144
145 mbus = ubus->mon_bus;
146 if (mbus != NULL)
147 mon_bus_complete(mbus, urb, status);
148 mon_bus_complete(&mon_bus0, urb, status);
149}
150
151/* int (*unlink_urb) (struct urb *urb, int status); */
152
153/*
154 * Stop monitoring.
155 */
156static void mon_stop(struct mon_bus *mbus)
157{
158 struct usb_bus *ubus;
159
160 if (mbus == &mon_bus0) {
161 list_for_each_entry(mbus, &mon_buses, bus_link) {
162 /*
163 * We do not change nreaders here, so rely on mon_lock.
164 */
165 if (mbus->nreaders == 0 && (ubus = mbus->u_bus) != NULL)
166 ubus->monitored = 0;
167 }
168 } else {
169 /*
170 * A stop can be called for a dissolved mon_bus in case of
171 * a reader staying across an rmmod foo_hcd, so test ->u_bus.
172 */
173 if (mon_bus0.nreaders == 0 && (ubus = mbus->u_bus) != NULL) {
174 ubus->monitored = 0;
175 mb();
176 }
177 }
178}
179
180/*
181 * Add a USB bus (usually by a modprobe foo-hcd)
182 *
183 * This does not return an error code because the core cannot care less
184 * if monitoring is not established.
185 */
186static void mon_bus_add(struct usb_bus *ubus)
187{
188 mon_bus_init(ubus);
189 mutex_lock(&mon_lock);
190 if (mon_bus0.nreaders != 0)
191 ubus->monitored = 1;
192 mutex_unlock(&mon_lock);
193}
194
195/*
196 * Remove a USB bus (either from rmmod foo-hcd or from a hot-remove event).
197 */
198static void mon_bus_remove(struct usb_bus *ubus)
199{
200 struct mon_bus *mbus = ubus->mon_bus;
201
202 mutex_lock(&mon_lock);
203 list_del(&mbus->bus_link);
204 if (mbus->text_inited)
205 mon_text_del(mbus);
206 if (mbus->bin_inited)
207 mon_bin_del(mbus);
208
209 mon_dissolve(mbus, ubus);
210 kref_put(&mbus->ref, mon_bus_drop);
211 mutex_unlock(&mon_lock);
212}
213
214static int mon_notify(struct notifier_block *self, unsigned long action,
215 void *dev)
216{
217 switch (action) {
218 case USB_BUS_ADD:
219 mon_bus_add(dev);
220 break;
221 case USB_BUS_REMOVE:
222 mon_bus_remove(dev);
223 }
224 return NOTIFY_OK;
225}
226
227static struct notifier_block mon_nb = {
228 .notifier_call = mon_notify,
229};
230
231/*
232 * Ops
233 */
234static const struct usb_mon_operations mon_ops_0 = {
235 .urb_submit = mon_submit,
236 .urb_submit_error = mon_submit_error,
237 .urb_complete = mon_complete,
238};
239
240/*
241 * Tear usb_bus and mon_bus apart.
242 */
243static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus)
244{
245
246 if (ubus->monitored) {
247 ubus->monitored = 0;
248 mb();
249 }
250
251 ubus->mon_bus = NULL;
252 mbus->u_bus = NULL;
253 mb();
254
255 /* We want synchronize_irq() here, but that needs an argument. */
256}
257
258/*
259 */
260static void mon_bus_drop(struct kref *r)
261{
262 struct mon_bus *mbus = container_of(r, struct mon_bus, ref);
263 kfree(mbus);
264}
265
266/*
267 * Initialize a bus for us:
268 * - allocate mon_bus
269 * - refcount USB bus struct
270 * - link
271 */
272static void mon_bus_init(struct usb_bus *ubus)
273{
274 struct mon_bus *mbus;
275
276 mbus = kzalloc(sizeof(struct mon_bus), GFP_KERNEL);
277 if (mbus == NULL)
278 goto err_alloc;
279 kref_init(&mbus->ref);
280 spin_lock_init(&mbus->lock);
281 INIT_LIST_HEAD(&mbus->r_list);
282
283 /*
284 * We don't need to take a reference to ubus, because we receive
285 * a notification if the bus is about to be removed.
286 */
287 mbus->u_bus = ubus;
288 ubus->mon_bus = mbus;
289
290 mbus->text_inited = mon_text_add(mbus, ubus);
291 mbus->bin_inited = mon_bin_add(mbus, ubus);
292
293 mutex_lock(&mon_lock);
294 list_add_tail(&mbus->bus_link, &mon_buses);
295 mutex_unlock(&mon_lock);
296 return;
297
298err_alloc:
299 return;
300}
301
302static void mon_bus0_init(void)
303{
304 struct mon_bus *mbus = &mon_bus0;
305
306 kref_init(&mbus->ref);
307 spin_lock_init(&mbus->lock);
308 INIT_LIST_HEAD(&mbus->r_list);
309
310 mbus->text_inited = mon_text_add(mbus, NULL);
311 mbus->bin_inited = mon_bin_add(mbus, NULL);
312}
313
314/*
315 * Search a USB bus by number. Notice that USB bus numbers start from one,
316 * which we may later use to identify "all" with zero.
317 *
318 * This function must be called with mon_lock held.
319 *
320 * This is obviously inefficient and may be revised in the future.
321 */
322struct mon_bus *mon_bus_lookup(unsigned int num)
323{
324 struct mon_bus *mbus;
325
326 if (num == 0) {
327 return &mon_bus0;
328 }
329 list_for_each_entry(mbus, &mon_buses, bus_link) {
330 if (mbus->u_bus->busnum == num) {
331 return mbus;
332 }
333 }
334 return NULL;
335}
336
337static int __init mon_init(void)
338{
339 struct usb_bus *ubus;
340 int rc, id;
341
342 if ((rc = mon_text_init()) != 0)
343 goto err_text;
344 if ((rc = mon_bin_init()) != 0)
345 goto err_bin;
346
347 mon_bus0_init();
348
349 if (usb_mon_register(&mon_ops_0) != 0) {
350 printk(KERN_NOTICE TAG ": unable to register with the core\n");
351 rc = -ENODEV;
352 goto err_reg;
353 }
354 // MOD_INC_USE_COUNT(which_module?);
355
356 mutex_lock(&usb_bus_idr_lock);
357 idr_for_each_entry(&usb_bus_idr, ubus, id)
358 mon_bus_init(ubus);
359 usb_register_notify(&mon_nb);
360 mutex_unlock(&usb_bus_idr_lock);
361 return 0;
362
363err_reg:
364 mon_bin_exit();
365err_bin:
366 mon_text_exit();
367err_text:
368 return rc;
369}
370
371static void __exit mon_exit(void)
372{
373 struct mon_bus *mbus;
374 struct list_head *p;
375
376 usb_unregister_notify(&mon_nb);
377 usb_mon_deregister();
378
379 mutex_lock(&mon_lock);
380
381 while (!list_empty(&mon_buses)) {
382 p = mon_buses.next;
383 mbus = list_entry(p, struct mon_bus, bus_link);
384 list_del(p);
385
386 if (mbus->text_inited)
387 mon_text_del(mbus);
388 if (mbus->bin_inited)
389 mon_bin_del(mbus);
390
391 /*
392 * This never happens, because the open/close paths in
393 * file level maintain module use counters and so rmmod fails
394 * before reaching here. However, better be safe...
395 */
396 if (mbus->nreaders) {
397 printk(KERN_ERR TAG
398 ": Outstanding opens (%d) on usb%d, leaking...\n",
399 mbus->nreaders, mbus->u_bus->busnum);
400 kref_get(&mbus->ref); /* Force leak */
401 }
402
403 mon_dissolve(mbus, mbus->u_bus);
404 kref_put(&mbus->ref, mon_bus_drop);
405 }
406
407 mbus = &mon_bus0;
408 if (mbus->text_inited)
409 mon_text_del(mbus);
410 if (mbus->bin_inited)
411 mon_bin_del(mbus);
412
413 mutex_unlock(&mon_lock);
414
415 mon_text_exit();
416 mon_bin_exit();
417}
418
419module_init(mon_init);
420module_exit(mon_exit);
421
422MODULE_LICENSE("GPL");