summaryrefslogtreecommitdiff
path: root/drivers/usb/usbip/stub_dev.c
blob: 9d7d642022d1f65b637a150ae1296a8af75eb017 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2003-2008 Takahiro Hirofuchi
 */

#include <linux/device.h>
#include <linux/file.h>
#include <linux/kthread.h>
#include <linux/module.h>

#include "usbip_common.h"
#include "stub.h"

/*
 * usbip_status shows the status of usbip-host as long as this driver is bound
 * to the target device.
 */
static ssize_t usbip_status_show(struct device *dev,
				 struct device_attribute *attr, char *buf)
{
	struct stub_device *sdev = dev_get_drvdata(dev);
	int status;

	if (!sdev) {
		dev_err(dev, "sdev is null\n");
		return -ENODEV;
	}

	spin_lock_irq(&sdev->ud.lock);
	status = sdev->ud.status;
	spin_unlock_irq(&sdev->ud.lock);

	return snprintf(buf, PAGE_SIZE, "%d\n", status);
}
static DEVICE_ATTR_RO(usbip_status);

/*
 * usbip_sockfd gets a socket descriptor of an established TCP connection that
 * is used to transfer usbip requests by kernel threads. -1 is a magic number
 * by which usbip connection is finished.
 */
static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *attr,
			    const char *buf, size_t count)
{
	struct stub_device *sdev = dev_get_drvdata(dev);
	int sockfd = 0;
	struct socket *socket;
	int rv;

	if (!sdev) {
		dev_err(dev, "sdev is null\n");
		return -ENODEV;
	}

	rv = sscanf(buf, "%d", &sockfd);
	if (rv != 1)
		return -EINVAL;

	if (sockfd != -1) {
		int err;

		dev_info(dev, "stub up\n");

		spin_lock_irq(&sdev->ud.lock);

		if (sdev->ud.status != SDEV_ST_AVAILABLE) {
			dev_err(dev, "not ready\n");
			goto err;
		}

		socket = sockfd_lookup(sockfd, &err);
		if (!socket)
			goto err;

		sdev->ud.tcp_socket = socket;
		sdev->ud.sockfd = sockfd;

		spin_unlock_irq(&sdev->ud.lock);

		sdev->ud.tcp_rx = kthread_get_run(stub_rx_loop, &sdev->ud,
						  "stub_rx");
		sdev->ud.tcp_tx = kthread_get_run(stub_tx_loop, &sdev->ud,
						  "stub_tx");

		spin_lock_irq(&sdev->ud.lock);
		sdev->ud.status = SDEV_ST_USED;
		spin_unlock_irq(&sdev->ud.lock);

	} else {
		dev_info(dev, "stub down\n");

		spin_lock_irq(&sdev->ud.lock);
		if (sdev->ud.status != SDEV_ST_USED)
			goto err;

		spin_unlock_irq(&sdev->ud.lock);

		usbip_event_add(&sdev->ud, SDEV_EVENT_DOWN);
	}

	return count;

err:
	spin_unlock_irq(&sdev->ud.lock);
	return -EINVAL;
}
static DEVICE_ATTR_WO(usbip_sockfd);

static struct attribute *usbip_attrs[] = {
	&dev_attr_usbip_status.attr,
	&dev_attr_usbip_sockfd.attr,
	&dev_attr_usbip_debug.attr,
	NULL,
};
ATTRIBUTE_GROUPS(usbip);

static void stub_shutdown_connection(struct usbip_device *ud)
{
	struct stub_device *sdev = container_of(ud, struct stub_device, ud);

	/*
	 * When removing an exported device, kernel panic sometimes occurred
	 * and then EIP was sk_wait_data of stub_rx thread. Is this because
	 * sk_wait_data returned though stub_rx thread was already finished by
	 * step 1?
	 */
	if (ud->tcp_socket) {
		dev_dbg(&sdev->udev->dev, "shutdown sockfd %d\n", ud->sockfd);
		kernel_sock_shutdown(ud->tcp_socket, SHUT_RDWR);
	}

	/* 1. stop threads */
	if (ud->tcp_rx) {
		kthread_stop_put(ud->tcp_rx);
		ud->tcp_rx = NULL;
	}
	if (ud->tcp_tx) {
		kthread_stop_put(ud->tcp_tx);
		ud->tcp_tx = NULL;
	}

	/*
	 * 2. close the socket
	 *
	 * tcp_socket is freed after threads are killed so that usbip_xmit does
	 * not touch NULL socket.
	 */
	if (ud->tcp_socket) {
		sockfd_put(ud->tcp_socket);
		ud->tcp_socket = NULL;
		ud->sockfd = -1;
	}

	/* 3. free used data */
	stub_device_cleanup_urbs(sdev);

	/* 4. free stub_unlink */
	{
		unsigned long flags;
		struct stub_unlink *unlink, *tmp;

		spin_lock_irqsave(&sdev->priv_lock, flags);
		list_for_each_entry_safe(unlink, tmp, &sdev->unlink_tx, list) {
			list_del(&unlink->list);
			kfree(unlink);
		}
		list_for_each_entry_safe(unlink, tmp, &sdev->unlink_free,
					 list) {
			list_del(&unlink->list);
			kfree(unlink);
		}
		spin_unlock_irqrestore(&sdev->priv_lock, flags);
	}
}

static void stub_device_reset(struct usbip_device *ud)
{
	struct stub_device *sdev = container_of(ud, struct stub_device, ud);
	struct usb_device *udev = sdev->udev;
	int ret;

	dev_dbg(&udev->dev, "device reset");

	ret = usb_lock_device_for_reset(udev, NULL);
	if (ret < 0) {
		dev_err(&udev->dev, "lock for reset\n");
		spin_lock_irq(&ud->lock);
		ud->status = SDEV_ST_ERROR;
		spin_unlock_irq(&ud->lock);
		return;
	}

	/* try to reset the device */
	ret = usb_reset_device(udev);
	usb_unlock_device(udev);

	spin_lock_irq(&ud->lock);
	if (ret) {
		dev_err(&udev->dev, "device reset\n");
		ud->status = SDEV_ST_ERROR;
	} else {
		dev_info(&udev->dev, "device reset\n");
		ud->status = SDEV_ST_AVAILABLE;
	}
	spin_unlock_irq(&ud->lock);
}

static void stub_device_unusable(struct usbip_device *ud)
{
	spin_lock_irq(&ud->lock);
	ud->status = SDEV_ST_ERROR;
	spin_unlock_irq(&ud->lock);
}

/**
 * stub_device_alloc - allocate a new stub_device struct
 * @udev: usb_device of a new device
 *
 * Allocates and initializes a new stub_device struct.
 */
static struct stub_device *stub_device_alloc(struct usb_device *udev)
{
	struct stub_device *sdev;
	int busnum = udev->bus->busnum;
	int devnum = udev->devnum;

	dev_dbg(&udev->dev, "allocating stub device");

	/* yes, it's a new device */
	sdev = kzalloc(sizeof(struct stub_device), GFP_KERNEL);
	if (!sdev)
		return NULL;

	sdev->udev = usb_get_dev(udev);

	/*
	 * devid is defined with devnum when this driver is first allocated.
	 * devnum may change later if a device is reset. However, devid never
	 * changes during a usbip connection.
	 */
	sdev->devid		= (busnum << 16) | devnum;
	sdev->ud.side		= USBIP_STUB;
	sdev->ud.status		= SDEV_ST_AVAILABLE;
	spin_lock_init(&sdev->ud.lock);
	sdev->ud.tcp_socket	= NULL;
	sdev->ud.sockfd		= -1;

	INIT_LIST_HEAD(&sdev->priv_init);
	INIT_LIST_HEAD(&sdev->priv_tx);
	INIT_LIST_HEAD(&sdev->priv_free);
	INIT_LIST_HEAD(&sdev->unlink_free);
	INIT_LIST_HEAD(&sdev->unlink_tx);
	spin_lock_init(&sdev->priv_lock);

	init_waitqueue_head(&sdev->tx_waitq);

	sdev->ud.eh_ops.shutdown = stub_shutdown_connection;
	sdev->ud.eh_ops.reset    = stub_device_reset;
	sdev->ud.eh_ops.unusable = stub_device_unusable;

	usbip_start_eh(&sdev->ud);

	dev_dbg(&udev->dev, "register new device\n");

	return sdev;
}

static void stub_device_free(struct stub_device *sdev)
{
	kfree(sdev);
}

static int stub_probe(struct usb_device *udev)
{
	struct stub_device *sdev = NULL;
	const char *udev_busid = dev_name(&udev->dev);
	struct bus_id_priv *busid_priv;
	int rc = 0;
	char save_status;

	dev_dbg(&udev->dev, "Enter probe\n");

	/* Not sure if this is our device. Allocate here to avoid
	 * calling alloc while holding busid_table lock.
	 */
	sdev = stub_device_alloc(udev);
	if (!sdev)
		return -ENOMEM;

	/* check we should claim or not by busid_table */
	busid_priv = get_busid_priv(udev_busid);
	if (!busid_priv || (busid_priv->status == STUB_BUSID_REMOV) ||
	    (busid_priv->status == STUB_BUSID_OTHER)) {
		dev_info(&udev->dev,
			"%s is not in match_busid table... skip!\n",
			udev_busid);

		/*
		 * Return value should be ENODEV or ENOXIO to continue trying
		 * other matched drivers by the driver core.
		 * See driver_probe_device() in driver/base/dd.c
		 */
		rc = -ENODEV;
		if (!busid_priv)
			goto sdev_free;

		goto call_put_busid_priv;
	}

	if (udev->descriptor.bDeviceClass == USB_CLASS_HUB) {
		dev_dbg(&udev->dev, "%s is a usb hub device... skip!\n",
			 udev_busid);
		rc = -ENODEV;
		goto call_put_busid_priv;
	}

	if (!strcmp(udev->bus->bus_name, "vhci_hcd")) {
		dev_dbg(&udev->dev,
			"%s is attached on vhci_hcd... skip!\n",
			udev_busid);

		rc = -ENODEV;
		goto call_put_busid_priv;
	}


	dev_info(&udev->dev,
		"usbip-host: register new device (bus %u dev %u)\n",
		udev->bus->busnum, udev->devnum);

	busid_priv->shutdown_busid = 0;

	/* set private data to usb_device */
	dev_set_drvdata(&udev->dev, sdev);

	busid_priv->sdev = sdev;
	busid_priv->udev = udev;

	save_status = busid_priv->status;
	busid_priv->status = STUB_BUSID_ALLOC;

	/* release the busid_lock */
	put_busid_priv(busid_priv);

	/*
	 * Claim this hub port.
	 * It doesn't matter what value we pass as owner
	 * (struct dev_state) as long as it is unique.
	 */
	rc = usb_hub_claim_port(udev->parent, udev->portnum,
			(struct usb_dev_state *) udev);
	if (rc) {
		dev_dbg(&udev->dev, "unable to claim port\n");
		goto err_port;
	}

	return 0;

err_port:
	dev_set_drvdata(&udev->dev, NULL);
	usb_put_dev(udev);

	/* we already have busid_priv, just lock busid_lock */
	spin_lock(&busid_priv->busid_lock);
	busid_priv->sdev = NULL;
	busid_priv->status = save_status;
	spin_unlock(&busid_priv->busid_lock);
	/* lock is released - go to free */
	goto sdev_free;

call_put_busid_priv:
	/* release the busid_lock */
	put_busid_priv(busid_priv);

sdev_free:
	stub_device_free(sdev);

	return rc;
}

static void shutdown_busid(struct bus_id_priv *busid_priv)
{
	usbip_event_add(&busid_priv->sdev->ud, SDEV_EVENT_REMOVED);

	/* wait for the stop of the event handler */
	usbip_stop_eh(&busid_priv->sdev->ud);
}

/*
 * called in usb_disconnect() or usb_deregister()
 * but only if actconfig(active configuration) exists
 */
static void stub_disconnect(struct usb_device *udev)
{
	struct stub_device *sdev;
	const char *udev_busid = dev_name(&udev->dev);
	struct bus_id_priv *busid_priv;
	int rc;

	dev_dbg(&udev->dev, "Enter disconnect\n");

	busid_priv = get_busid_priv(udev_busid);
	if (!busid_priv) {
		BUG();
		return;
	}

	sdev = dev_get_drvdata(&udev->dev);

	/* get stub_device */
	if (!sdev) {
		dev_err(&udev->dev, "could not get device");
		/* release busid_lock */
		put_busid_priv(busid_priv);
		return;
	}

	dev_set_drvdata(&udev->dev, NULL);

	/* release busid_lock before call to remove device files */
	put_busid_priv(busid_priv);

	/*
	 * NOTE: rx/tx threads are invoked for each usb_device.
	 */

	/* release port */
	rc = usb_hub_release_port(udev->parent, udev->portnum,
				  (struct usb_dev_state *) udev);
	if (rc) {
		dev_dbg(&udev->dev, "unable to release port\n");
		return;
	}

	/* If usb reset is called from event handler */
	if (usbip_in_eh(current))
		return;

	/* we already have busid_priv, just lock busid_lock */
	spin_lock(&busid_priv->busid_lock);
	if (!busid_priv->shutdown_busid)
		busid_priv->shutdown_busid = 1;
	/* release busid_lock */
	spin_unlock(&busid_priv->busid_lock);

	/* shutdown the current connection */
	shutdown_busid(busid_priv);

	usb_put_dev(sdev->udev);

	/* we already have busid_priv, just lock busid_lock */
	spin_lock(&busid_priv->busid_lock);
	/* free sdev */
	busid_priv->sdev = NULL;
	stub_device_free(sdev);

	if (busid_priv->status == STUB_BUSID_ALLOC)
		busid_priv->status = STUB_BUSID_ADDED;
	/* release busid_lock */
	spin_unlock(&busid_priv->busid_lock);
	return;
}

static bool usbip_match(struct usb_device *udev)
{
	return true;
}

#ifdef CONFIG_PM

/* These functions need usb_port_suspend and usb_port_resume,
 * which reside in drivers/usb/core/usb.h. Skip for now. */

static int stub_suspend(struct usb_device *udev, pm_message_t message)
{
	dev_dbg(&udev->dev, "stub_suspend\n");

	return 0;
}

static int stub_resume(struct usb_device *udev, pm_message_t message)
{
	dev_dbg(&udev->dev, "stub_resume\n");

	return 0;
}

#endif	/* CONFIG_PM */

struct usb_device_driver stub_driver = {
	.name		= "usbip-host",
	.probe		= stub_probe,
	.disconnect	= stub_disconnect,
	.match		= usbip_match,
#ifdef CONFIG_PM
	.suspend	= stub_suspend,
	.resume		= stub_resume,
#endif
	.supports_autosuspend	=	0,
	.dev_groups	= usbip_groups,
};