[PATCH] USB: kzalloc() conversion for rest of drivers/usb
[linux-2.6-block.git] / drivers / usb / mon / mon_main.c
CommitLineData
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 *
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>
12#include <linux/debugfs.h>
13#include <linux/smp_lock.h>
72adaa96 14#include <linux/notifier.h>
4186ecf8 15#include <linux/mutex.h>
1da177e4
LT
16
17#include "usb_mon.h"
18#include "../core/hcd.h"
19
20static void mon_submit(struct usb_bus *ubus, struct urb *urb);
21static void mon_complete(struct usb_bus *ubus, struct urb *urb);
22static void mon_stop(struct mon_bus *mbus);
23static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus);
24static void mon_bus_drop(struct kref *r);
25static void mon_bus_init(struct dentry *mondir, struct usb_bus *ubus);
26
4186ecf8 27DEFINE_MUTEX(mon_lock);
1da177e4
LT
28
29static struct dentry *mon_dir; /* /dbg/usbmon */
30static LIST_HEAD(mon_buses); /* All buses we know: struct mon_bus */
31
32/*
33 * Link a reader into the bus.
34 *
35 * This must be called with mon_lock taken because of mbus->ref.
36 */
37void mon_reader_add(struct mon_bus *mbus, struct mon_reader *r)
38{
39 unsigned long flags;
40 struct usb_bus *ubus;
41
42 spin_lock_irqsave(&mbus->lock, flags);
43 if (mbus->nreaders == 0) {
44 ubus = mbus->u_bus;
45 if (ubus->monitored) {
46 /*
47 * Something is really broken, refuse to go on and
48 * possibly corrupt ops pointers or worse.
49 */
50 printk(KERN_ERR TAG ": bus %d is already monitored\n",
51 ubus->busnum);
52 spin_unlock_irqrestore(&mbus->lock, flags);
53 return;
54 }
55 ubus->monitored = 1;
56 }
57 mbus->nreaders++;
58 list_add_tail(&r->r_link, &mbus->r_list);
59 spin_unlock_irqrestore(&mbus->lock, flags);
60
61 kref_get(&mbus->ref);
62}
63
64/*
65 * Unlink reader from the bus.
66 *
67 * This is called with mon_lock taken, so we can decrement mbus->ref.
68 */
69void mon_reader_del(struct mon_bus *mbus, struct mon_reader *r)
70{
71 unsigned long flags;
72
73 spin_lock_irqsave(&mbus->lock, flags);
74 list_del(&r->r_link);
75 --mbus->nreaders;
76 if (mbus->nreaders == 0)
77 mon_stop(mbus);
78 spin_unlock_irqrestore(&mbus->lock, flags);
79
80 kref_put(&mbus->ref, mon_bus_drop);
81}
82
83/*
84 */
85static void mon_submit(struct usb_bus *ubus, struct urb *urb)
86{
87 struct mon_bus *mbus;
88 unsigned long flags;
89 struct list_head *pos;
90 struct mon_reader *r;
91
92 mbus = ubus->mon_bus;
93 if (mbus == NULL)
94 goto out_unlocked;
95
96 spin_lock_irqsave(&mbus->lock, flags);
97 if (mbus->nreaders == 0)
98 goto out_locked;
99
100 list_for_each (pos, &mbus->r_list) {
101 r = list_entry(pos, struct mon_reader, r_link);
102 r->rnf_submit(r->r_data, urb);
103 }
104
105 spin_unlock_irqrestore(&mbus->lock, flags);
106 return;
107
108out_locked:
109 spin_unlock_irqrestore(&mbus->lock, flags);
110out_unlocked:
111 return;
112}
113
114/*
115 */
116static void mon_submit_error(struct usb_bus *ubus, struct urb *urb, int err)
117{
118 struct mon_bus *mbus;
119
120 mbus = ubus->mon_bus;
121 if (mbus == NULL)
122 goto out_unlocked;
123
124 /*
125 * XXX Capture the error code and the 'E' event.
126 */
127
128 return;
129
130out_unlocked:
131 return;
132}
133
134/*
135 */
136static void mon_complete(struct usb_bus *ubus, struct urb *urb)
137{
138 struct mon_bus *mbus;
139 unsigned long flags;
140 struct list_head *pos;
141 struct mon_reader *r;
142
143 mbus = ubus->mon_bus;
144 if (mbus == NULL) {
145 /*
146 * This should not happen.
147 * At this point we do not even know the bus number...
148 */
149 printk(KERN_ERR TAG ": Null mon bus in URB, pipe 0x%x\n",
150 urb->pipe);
151 return;
152 }
153
154 spin_lock_irqsave(&mbus->lock, flags);
155 list_for_each (pos, &mbus->r_list) {
156 r = list_entry(pos, struct mon_reader, r_link);
157 r->rnf_complete(r->r_data, urb);
158 }
159 spin_unlock_irqrestore(&mbus->lock, flags);
160}
161
162/* int (*unlink_urb) (struct urb *urb, int status); */
163
164/*
165 * Stop monitoring.
166 * Obviously this must be well locked, so no need to play with mb's.
167 */
168static void mon_stop(struct mon_bus *mbus)
169{
170 struct usb_bus *ubus = mbus->u_bus;
171
172 /*
173 * A stop can be called for a dissolved mon_bus in case of
174 * a reader staying across an rmmod foo_hcd.
175 */
176 if (ubus != NULL) {
177 ubus->monitored = 0;
178 mb();
179 }
180}
181
182/*
183 * Add a USB bus (usually by a modprobe foo-hcd)
184 *
185 * This does not return an error code because the core cannot care less
186 * if monitoring is not established.
187 */
188static void mon_bus_add(struct usb_bus *ubus)
189{
190 mon_bus_init(mon_dir, ubus);
191}
192
193/*
194 * Remove a USB bus (either from rmmod foo-hcd or from a hot-remove event).
195 */
196static void mon_bus_remove(struct usb_bus *ubus)
197{
198 struct mon_bus *mbus = ubus->mon_bus;
199
4186ecf8 200 mutex_lock(&mon_lock);
1da177e4
LT
201 list_del(&mbus->bus_link);
202 debugfs_remove(mbus->dent_t);
203 debugfs_remove(mbus->dent_s);
204
205 mon_dissolve(mbus, ubus);
206 kref_put(&mbus->ref, mon_bus_drop);
4186ecf8 207 mutex_unlock(&mon_lock);
1da177e4
LT
208}
209
72adaa96
GKH
210static int mon_notify(struct notifier_block *self, unsigned long action,
211 void *dev)
212{
213 switch (action) {
214 case USB_BUS_ADD:
215 mon_bus_add(dev);
216 break;
217 case USB_BUS_REMOVE:
218 mon_bus_remove(dev);
219 }
220 return NOTIFY_OK;
221}
222
223static struct notifier_block mon_nb = {
224 .notifier_call = mon_notify,
225};
226
1da177e4
LT
227/*
228 * Ops
229 */
230static struct usb_mon_operations mon_ops_0 = {
231 .urb_submit = mon_submit,
232 .urb_submit_error = mon_submit_error,
233 .urb_complete = mon_complete,
1da177e4
LT
234};
235
236/*
237 * Tear usb_bus and mon_bus apart.
238 */
239static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus)
240{
241
242 /*
243 * Never happens, but...
244 */
245 if (ubus->monitored) {
246 printk(KERN_ERR TAG ": bus %d is dissolved while monitored\n",
247 ubus->busnum);
248 ubus->monitored = 0;
249 mb();
250 }
251
252 ubus->mon_bus = NULL;
253 mbus->u_bus = NULL;
254 mb();
255 // usb_bus_put(ubus);
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 dentry *mondir, struct usb_bus *ubus)
273{
274 struct dentry *d;
275 struct mon_bus *mbus;
276 enum { NAMESZ = 10 };
277 char name[NAMESZ];
278 int rc;
279
80b6ca48 280 if ((mbus = kzalloc(sizeof(struct mon_bus), GFP_KERNEL)) == NULL)
1da177e4 281 goto err_alloc;
1da177e4
LT
282 kref_init(&mbus->ref);
283 spin_lock_init(&mbus->lock);
284 INIT_LIST_HEAD(&mbus->r_list);
285
286 /*
287 * This usb_bus_get here is superfluous, because we receive
288 * a notification if usb_bus is about to be removed.
289 */
290 // usb_bus_get(ubus);
291 mbus->u_bus = ubus;
292 ubus->mon_bus = mbus;
293
294 rc = snprintf(name, NAMESZ, "%dt", ubus->busnum);
295 if (rc <= 0 || rc >= NAMESZ)
296 goto err_print_t;
297 d = debugfs_create_file(name, 0600, mondir, mbus, &mon_fops_text);
298 if (d == NULL)
299 goto err_create_t;
300 mbus->dent_t = d;
301
302 rc = snprintf(name, NAMESZ, "%ds", ubus->busnum);
303 if (rc <= 0 || rc >= NAMESZ)
304 goto err_print_s;
305 d = debugfs_create_file(name, 0600, mondir, mbus, &mon_fops_stat);
306 if (d == NULL)
307 goto err_create_s;
308 mbus->dent_s = d;
309
4186ecf8 310 mutex_lock(&mon_lock);
1da177e4 311 list_add_tail(&mbus->bus_link, &mon_buses);
4186ecf8 312 mutex_unlock(&mon_lock);
1da177e4
LT
313 return;
314
315err_create_s:
316err_print_s:
317 debugfs_remove(mbus->dent_t);
318err_create_t:
319err_print_t:
320 kfree(mbus);
321err_alloc:
322 return;
323}
324
325static int __init mon_init(void)
326{
327 struct usb_bus *ubus;
328 struct dentry *mondir;
329
330 mondir = debugfs_create_dir("usbmon", NULL);
331 if (IS_ERR(mondir)) {
da5ca008 332 printk(KERN_NOTICE TAG ": debugfs is not available\n");
1da177e4
LT
333 return -ENODEV;
334 }
335 if (mondir == NULL) {
336 printk(KERN_NOTICE TAG ": unable to create usbmon directory\n");
337 return -ENODEV;
338 }
339 mon_dir = mondir;
340
341 if (usb_mon_register(&mon_ops_0) != 0) {
342 printk(KERN_NOTICE TAG ": unable to register with the core\n");
343 debugfs_remove(mondir);
344 return -ENODEV;
345 }
346 // MOD_INC_USE_COUNT(which_module?);
347
72adaa96
GKH
348 usb_register_notify(&mon_nb);
349
4186ecf8 350 mutex_lock(&usb_bus_list_lock);
1da177e4
LT
351 list_for_each_entry (ubus, &usb_bus_list, bus_list) {
352 mon_bus_init(mondir, ubus);
353 }
4186ecf8 354 mutex_unlock(&usb_bus_list_lock);
1da177e4
LT
355 return 0;
356}
357
358static void __exit mon_exit(void)
359{
360 struct mon_bus *mbus;
361 struct list_head *p;
362
72adaa96 363 usb_unregister_notify(&mon_nb);
1da177e4
LT
364 usb_mon_deregister();
365
4186ecf8 366 mutex_lock(&mon_lock);
1da177e4
LT
367 while (!list_empty(&mon_buses)) {
368 p = mon_buses.next;
369 mbus = list_entry(p, struct mon_bus, bus_link);
370 list_del(p);
371
372 debugfs_remove(mbus->dent_t);
373 debugfs_remove(mbus->dent_s);
374
375 /*
376 * This never happens, because the open/close paths in
377 * file level maintain module use counters and so rmmod fails
378 * before reaching here. However, better be safe...
379 */
380 if (mbus->nreaders) {
381 printk(KERN_ERR TAG
382 ": Outstanding opens (%d) on usb%d, leaking...\n",
383 mbus->nreaders, mbus->u_bus->busnum);
384 atomic_set(&mbus->ref.refcount, 2); /* Force leak */
385 }
386
387 mon_dissolve(mbus, mbus->u_bus);
388 kref_put(&mbus->ref, mon_bus_drop);
389 }
4186ecf8 390 mutex_unlock(&mon_lock);
1da177e4
LT
391
392 debugfs_remove(mon_dir);
393}
394
395module_init(mon_init);
396module_exit(mon_exit);
397
398MODULE_LICENSE("GPL");