xref: /openbmc/linux/drivers/net/usb/usbnet.c (revision 808643ea)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * USB Network driver infrastructure
4  * Copyright (C) 2000-2005 by David Brownell
5  * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.com>
6  */
7 
8 /*
9  * This is a generic "USB networking" framework that works with several
10  * kinds of full and high speed networking devices:  host-to-host cables,
11  * smart usb peripherals, and actual Ethernet adapters.
12  *
13  * These devices usually differ in terms of control protocols (if they
14  * even have one!) and sometimes they define new framing to wrap or batch
15  * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
16  * so interface (un)binding, endpoint I/O queues, fault handling, and other
17  * issues can usefully be addressed by this framework.
18  */
19 
20 // #define	DEBUG			// error path messages, extra info
21 // #define	VERBOSE			// more; success messages
22 
23 #include <linux/module.h>
24 #include <linux/init.h>
25 #include <linux/netdevice.h>
26 #include <linux/etherdevice.h>
27 #include <linux/ctype.h>
28 #include <linux/ethtool.h>
29 #include <linux/workqueue.h>
30 #include <linux/mii.h>
31 #include <linux/usb.h>
32 #include <linux/usb/usbnet.h>
33 #include <linux/slab.h>
34 #include <linux/kernel.h>
35 #include <linux/pm_runtime.h>
36 
37 /*-------------------------------------------------------------------------*/
38 
39 /*
40  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
41  * Several dozen bytes of IPv4 data can fit in two such transactions.
42  * One maximum size Ethernet packet takes twenty four of them.
43  * For high speed, each frame comfortably fits almost 36 max size
44  * Ethernet packets (so queues should be bigger).
45  *
46  * The goal is to let the USB host controller be busy for 5msec or
47  * more before an irq is required, under load.  Jumbograms change
48  * the equation.
49  */
50 #define	MAX_QUEUE_MEMORY	(60 * 1518)
51 #define	RX_QLEN(dev)		((dev)->rx_qlen)
52 #define	TX_QLEN(dev)		((dev)->tx_qlen)
53 
54 // reawaken network queue this soon after stopping; else watchdog barks
55 #define TX_TIMEOUT_JIFFIES	(5*HZ)
56 
57 /* throttle rx/tx briefly after some faults, so hub_wq might disconnect()
58  * us (it polls at HZ/4 usually) before we report too many false errors.
59  */
60 #define THROTTLE_JIFFIES	(HZ/8)
61 
62 // between wakeups
63 #define UNLINK_TIMEOUT_MS	3
64 
65 /*-------------------------------------------------------------------------*/
66 
67 // randomly generated ethernet address
68 static u8	node_id [ETH_ALEN];
69 
70 /* use ethtool to change the level for any given device */
71 static int msg_level = -1;
72 module_param (msg_level, int, 0);
73 MODULE_PARM_DESC (msg_level, "Override default message level");
74 
75 /*-------------------------------------------------------------------------*/
76 
77 static const char * const usbnet_event_names[] = {
78 	[EVENT_TX_HALT]		   = "EVENT_TX_HALT",
79 	[EVENT_RX_HALT]		   = "EVENT_RX_HALT",
80 	[EVENT_RX_MEMORY]	   = "EVENT_RX_MEMORY",
81 	[EVENT_STS_SPLIT]	   = "EVENT_STS_SPLIT",
82 	[EVENT_LINK_RESET]	   = "EVENT_LINK_RESET",
83 	[EVENT_RX_PAUSED]	   = "EVENT_RX_PAUSED",
84 	[EVENT_DEV_ASLEEP]	   = "EVENT_DEV_ASLEEP",
85 	[EVENT_DEV_OPEN]	   = "EVENT_DEV_OPEN",
86 	[EVENT_DEVICE_REPORT_IDLE] = "EVENT_DEVICE_REPORT_IDLE",
87 	[EVENT_NO_RUNTIME_PM]	   = "EVENT_NO_RUNTIME_PM",
88 	[EVENT_RX_KILL]		   = "EVENT_RX_KILL",
89 	[EVENT_LINK_CHANGE]	   = "EVENT_LINK_CHANGE",
90 	[EVENT_SET_RX_MODE]	   = "EVENT_SET_RX_MODE",
91 	[EVENT_NO_IP_ALIGN]	   = "EVENT_NO_IP_ALIGN",
92 };
93 
94 /* handles CDC Ethernet and many other network "bulk data" interfaces */
95 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
96 {
97 	int				tmp;
98 	struct usb_host_interface	*alt = NULL;
99 	struct usb_host_endpoint	*in = NULL, *out = NULL;
100 	struct usb_host_endpoint	*status = NULL;
101 
102 	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
103 		unsigned	ep;
104 
105 		in = out = status = NULL;
106 		alt = intf->altsetting + tmp;
107 
108 		/* take the first altsetting with in-bulk + out-bulk;
109 		 * remember any status endpoint, just in case;
110 		 * ignore other endpoints and altsettings.
111 		 */
112 		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
113 			struct usb_host_endpoint	*e;
114 			int				intr = 0;
115 
116 			e = alt->endpoint + ep;
117 
118 			/* ignore endpoints which cannot transfer data */
119 			if (!usb_endpoint_maxp(&e->desc))
120 				continue;
121 
122 			switch (e->desc.bmAttributes) {
123 			case USB_ENDPOINT_XFER_INT:
124 				if (!usb_endpoint_dir_in(&e->desc))
125 					continue;
126 				intr = 1;
127 				fallthrough;
128 			case USB_ENDPOINT_XFER_BULK:
129 				break;
130 			default:
131 				continue;
132 			}
133 			if (usb_endpoint_dir_in(&e->desc)) {
134 				if (!intr && !in)
135 					in = e;
136 				else if (intr && !status)
137 					status = e;
138 			} else {
139 				if (!out)
140 					out = e;
141 			}
142 		}
143 		if (in && out)
144 			break;
145 	}
146 	if (!alt || !in || !out)
147 		return -EINVAL;
148 
149 	if (alt->desc.bAlternateSetting != 0 ||
150 	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
151 		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
152 				alt->desc.bAlternateSetting);
153 		if (tmp < 0)
154 			return tmp;
155 	}
156 
157 	dev->in = usb_rcvbulkpipe (dev->udev,
158 			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
159 	dev->out = usb_sndbulkpipe (dev->udev,
160 			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
161 	dev->status = status;
162 	return 0;
163 }
164 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
165 
166 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
167 {
168 	int 		tmp = -1, ret;
169 	unsigned char	buf [13];
170 
171 	ret = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
172 	if (ret == 12)
173 		tmp = hex2bin(dev->net->dev_addr, buf, 6);
174 	if (tmp < 0) {
175 		dev_dbg(&dev->udev->dev,
176 			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
177 		if (ret >= 0)
178 			ret = -EINVAL;
179 		return ret;
180 	}
181 	return 0;
182 }
183 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
184 
185 static void intr_complete (struct urb *urb)
186 {
187 	struct usbnet	*dev = urb->context;
188 	int		status = urb->status;
189 
190 	switch (status) {
191 	/* success */
192 	case 0:
193 		dev->driver_info->status(dev, urb);
194 		break;
195 
196 	/* software-driven interface shutdown */
197 	case -ENOENT:		/* urb killed */
198 	case -ESHUTDOWN:	/* hardware gone */
199 		netif_dbg(dev, ifdown, dev->net,
200 			  "intr shutdown, code %d\n", status);
201 		return;
202 
203 	/* NOTE:  not throttling like RX/TX, since this endpoint
204 	 * already polls infrequently
205 	 */
206 	default:
207 		netdev_dbg(dev->net, "intr status %d\n", status);
208 		break;
209 	}
210 
211 	status = usb_submit_urb (urb, GFP_ATOMIC);
212 	if (status != 0)
213 		netif_err(dev, timer, dev->net,
214 			  "intr resubmit --> %d\n", status);
215 }
216 
217 static int init_status (struct usbnet *dev, struct usb_interface *intf)
218 {
219 	char		*buf = NULL;
220 	unsigned	pipe = 0;
221 	unsigned	maxp;
222 	unsigned	period;
223 
224 	if (!dev->driver_info->status)
225 		return 0;
226 
227 	pipe = usb_rcvintpipe (dev->udev,
228 			dev->status->desc.bEndpointAddress
229 				& USB_ENDPOINT_NUMBER_MASK);
230 	maxp = usb_maxpacket (dev->udev, pipe, 0);
231 
232 	/* avoid 1 msec chatter:  min 8 msec poll rate */
233 	period = max ((int) dev->status->desc.bInterval,
234 		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
235 
236 	buf = kmalloc (maxp, GFP_KERNEL);
237 	if (buf) {
238 		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
239 		if (!dev->interrupt) {
240 			kfree (buf);
241 			return -ENOMEM;
242 		} else {
243 			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
244 				buf, maxp, intr_complete, dev, period);
245 			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
246 			dev_dbg(&intf->dev,
247 				"status ep%din, %d bytes period %d\n",
248 				usb_pipeendpoint(pipe), maxp, period);
249 		}
250 	}
251 	return 0;
252 }
253 
254 /* Submit the interrupt URB if not previously submitted, increasing refcount */
255 int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
256 {
257 	int ret = 0;
258 
259 	WARN_ON_ONCE(dev->interrupt == NULL);
260 	if (dev->interrupt) {
261 		mutex_lock(&dev->interrupt_mutex);
262 
263 		if (++dev->interrupt_count == 1)
264 			ret = usb_submit_urb(dev->interrupt, mem_flags);
265 
266 		dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
267 			dev->interrupt_count);
268 		mutex_unlock(&dev->interrupt_mutex);
269 	}
270 	return ret;
271 }
272 EXPORT_SYMBOL_GPL(usbnet_status_start);
273 
274 /* For resume; submit interrupt URB if previously submitted */
275 static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
276 {
277 	int ret = 0;
278 
279 	mutex_lock(&dev->interrupt_mutex);
280 	if (dev->interrupt_count) {
281 		ret = usb_submit_urb(dev->interrupt, mem_flags);
282 		dev_dbg(&dev->udev->dev,
283 			"submitted interrupt URB for resume\n");
284 	}
285 	mutex_unlock(&dev->interrupt_mutex);
286 	return ret;
287 }
288 
289 /* Kill the interrupt URB if all submitters want it killed */
290 void usbnet_status_stop(struct usbnet *dev)
291 {
292 	if (dev->interrupt) {
293 		mutex_lock(&dev->interrupt_mutex);
294 		WARN_ON(dev->interrupt_count == 0);
295 
296 		if (dev->interrupt_count && --dev->interrupt_count == 0)
297 			usb_kill_urb(dev->interrupt);
298 
299 		dev_dbg(&dev->udev->dev,
300 			"decremented interrupt URB count to %d\n",
301 			dev->interrupt_count);
302 		mutex_unlock(&dev->interrupt_mutex);
303 	}
304 }
305 EXPORT_SYMBOL_GPL(usbnet_status_stop);
306 
307 /* For suspend; always kill interrupt URB */
308 static void __usbnet_status_stop_force(struct usbnet *dev)
309 {
310 	if (dev->interrupt) {
311 		mutex_lock(&dev->interrupt_mutex);
312 		usb_kill_urb(dev->interrupt);
313 		dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
314 		mutex_unlock(&dev->interrupt_mutex);
315 	}
316 }
317 
318 /* Passes this packet up the stack, updating its accounting.
319  * Some link protocols batch packets, so their rx_fixup paths
320  * can return clones as well as just modify the original skb.
321  */
322 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
323 {
324 	struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->net->tstats);
325 	unsigned long flags;
326 	int	status;
327 
328 	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
329 		skb_queue_tail(&dev->rxq_pause, skb);
330 		return;
331 	}
332 
333 	/* only update if unset to allow minidriver rx_fixup override */
334 	if (skb->protocol == 0)
335 		skb->protocol = eth_type_trans (skb, dev->net);
336 
337 	flags = u64_stats_update_begin_irqsave(&stats64->syncp);
338 	stats64->rx_packets++;
339 	stats64->rx_bytes += skb->len;
340 	u64_stats_update_end_irqrestore(&stats64->syncp, flags);
341 
342 	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
343 		  skb->len + sizeof (struct ethhdr), skb->protocol);
344 	memset (skb->cb, 0, sizeof (struct skb_data));
345 
346 	if (skb_defer_rx_timestamp(skb))
347 		return;
348 
349 	status = netif_rx (skb);
350 	if (status != NET_RX_SUCCESS)
351 		netif_dbg(dev, rx_err, dev->net,
352 			  "netif_rx status %d\n", status);
353 }
354 EXPORT_SYMBOL_GPL(usbnet_skb_return);
355 
356 /* must be called if hard_mtu or rx_urb_size changed */
357 void usbnet_update_max_qlen(struct usbnet *dev)
358 {
359 	enum usb_device_speed speed = dev->udev->speed;
360 
361 	if (!dev->rx_urb_size || !dev->hard_mtu)
362 		goto insanity;
363 	switch (speed) {
364 	case USB_SPEED_HIGH:
365 		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
366 		dev->tx_qlen = MAX_QUEUE_MEMORY / dev->hard_mtu;
367 		break;
368 	case USB_SPEED_SUPER:
369 	case USB_SPEED_SUPER_PLUS:
370 		/*
371 		 * Not take default 5ms qlen for super speed HC to
372 		 * save memory, and iperf tests show 2.5ms qlen can
373 		 * work well
374 		 */
375 		dev->rx_qlen = 5 * MAX_QUEUE_MEMORY / dev->rx_urb_size;
376 		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
377 		break;
378 	default:
379 insanity:
380 		dev->rx_qlen = dev->tx_qlen = 4;
381 	}
382 }
383 EXPORT_SYMBOL_GPL(usbnet_update_max_qlen);
384 
385 
386 /*-------------------------------------------------------------------------
387  *
388  * Network Device Driver (peer link to "Host Device", from USB host)
389  *
390  *-------------------------------------------------------------------------*/
391 
392 int usbnet_change_mtu (struct net_device *net, int new_mtu)
393 {
394 	struct usbnet	*dev = netdev_priv(net);
395 	int		ll_mtu = new_mtu + net->hard_header_len;
396 	int		old_hard_mtu = dev->hard_mtu;
397 	int		old_rx_urb_size = dev->rx_urb_size;
398 
399 	// no second zero-length packet read wanted after mtu-sized packets
400 	if ((ll_mtu % dev->maxpacket) == 0)
401 		return -EDOM;
402 	net->mtu = new_mtu;
403 
404 	dev->hard_mtu = net->mtu + net->hard_header_len;
405 	if (dev->rx_urb_size == old_hard_mtu) {
406 		dev->rx_urb_size = dev->hard_mtu;
407 		if (dev->rx_urb_size > old_rx_urb_size) {
408 			usbnet_pause_rx(dev);
409 			usbnet_unlink_rx_urbs(dev);
410 			usbnet_resume_rx(dev);
411 		}
412 	}
413 
414 	/* max qlen depend on hard_mtu and rx_urb_size */
415 	usbnet_update_max_qlen(dev);
416 
417 	return 0;
418 }
419 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
420 
421 /* The caller must hold list->lock */
422 static void __usbnet_queue_skb(struct sk_buff_head *list,
423 			struct sk_buff *newsk, enum skb_state state)
424 {
425 	struct skb_data *entry = (struct skb_data *) newsk->cb;
426 
427 	__skb_queue_tail(list, newsk);
428 	entry->state = state;
429 }
430 
431 /*-------------------------------------------------------------------------*/
432 
433 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
434  * completion callbacks.  2.5 should have fixed those bugs...
435  */
436 
437 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
438 		struct sk_buff_head *list, enum skb_state state)
439 {
440 	unsigned long		flags;
441 	enum skb_state 		old_state;
442 	struct skb_data *entry = (struct skb_data *) skb->cb;
443 
444 	spin_lock_irqsave(&list->lock, flags);
445 	old_state = entry->state;
446 	entry->state = state;
447 	__skb_unlink(skb, list);
448 
449 	/* defer_bh() is never called with list == &dev->done.
450 	 * spin_lock_nested() tells lockdep that it is OK to take
451 	 * dev->done.lock here with list->lock held.
452 	 */
453 	spin_lock_nested(&dev->done.lock, SINGLE_DEPTH_NESTING);
454 
455 	__skb_queue_tail(&dev->done, skb);
456 	if (dev->done.qlen == 1)
457 		tasklet_schedule(&dev->bh);
458 	spin_unlock(&dev->done.lock);
459 	spin_unlock_irqrestore(&list->lock, flags);
460 	return old_state;
461 }
462 
463 /* some work can't be done in tasklets, so we use keventd
464  *
465  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
466  * but tasklet_schedule() doesn't.  hope the failure is rare.
467  */
468 void usbnet_defer_kevent (struct usbnet *dev, int work)
469 {
470 	set_bit (work, &dev->flags);
471 	if (!schedule_work (&dev->kevent))
472 		netdev_dbg(dev->net, "kevent %s may have been dropped\n", usbnet_event_names[work]);
473 	else
474 		netdev_dbg(dev->net, "kevent %s scheduled\n", usbnet_event_names[work]);
475 }
476 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
477 
478 /*-------------------------------------------------------------------------*/
479 
480 static void rx_complete (struct urb *urb);
481 
482 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
483 {
484 	struct sk_buff		*skb;
485 	struct skb_data		*entry;
486 	int			retval = 0;
487 	unsigned long		lockflags;
488 	size_t			size = dev->rx_urb_size;
489 
490 	/* prevent rx skb allocation when error ratio is high */
491 	if (test_bit(EVENT_RX_KILL, &dev->flags)) {
492 		usb_free_urb(urb);
493 		return -ENOLINK;
494 	}
495 
496 	if (test_bit(EVENT_NO_IP_ALIGN, &dev->flags))
497 		skb = __netdev_alloc_skb(dev->net, size, flags);
498 	else
499 		skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
500 	if (!skb) {
501 		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
502 		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
503 		usb_free_urb (urb);
504 		return -ENOMEM;
505 	}
506 
507 	entry = (struct skb_data *) skb->cb;
508 	entry->urb = urb;
509 	entry->dev = dev;
510 	entry->length = 0;
511 
512 	usb_fill_bulk_urb (urb, dev->udev, dev->in,
513 		skb->data, size, rx_complete, skb);
514 
515 	spin_lock_irqsave (&dev->rxq.lock, lockflags);
516 
517 	if (netif_running (dev->net) &&
518 	    netif_device_present (dev->net) &&
519 	    test_bit(EVENT_DEV_OPEN, &dev->flags) &&
520 	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
521 	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
522 		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
523 		case -EPIPE:
524 			usbnet_defer_kevent (dev, EVENT_RX_HALT);
525 			break;
526 		case -ENOMEM:
527 			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
528 			break;
529 		case -ENODEV:
530 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
531 			netif_device_detach (dev->net);
532 			break;
533 		case -EHOSTUNREACH:
534 			retval = -ENOLINK;
535 			break;
536 		default:
537 			netif_dbg(dev, rx_err, dev->net,
538 				  "rx submit, %d\n", retval);
539 			tasklet_schedule (&dev->bh);
540 			break;
541 		case 0:
542 			__usbnet_queue_skb(&dev->rxq, skb, rx_start);
543 		}
544 	} else {
545 		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
546 		retval = -ENOLINK;
547 	}
548 	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
549 	if (retval) {
550 		dev_kfree_skb_any (skb);
551 		usb_free_urb (urb);
552 	}
553 	return retval;
554 }
555 
556 
557 /*-------------------------------------------------------------------------*/
558 
559 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
560 {
561 	if (dev->driver_info->rx_fixup &&
562 	    !dev->driver_info->rx_fixup (dev, skb)) {
563 		/* With RX_ASSEMBLE, rx_fixup() must update counters */
564 		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
565 			dev->net->stats.rx_errors++;
566 		goto done;
567 	}
568 	// else network stack removes extra byte if we forced a short packet
569 
570 	/* all data was already cloned from skb inside the driver */
571 	if (dev->driver_info->flags & FLAG_MULTI_PACKET)
572 		goto done;
573 
574 	if (skb->len < ETH_HLEN) {
575 		dev->net->stats.rx_errors++;
576 		dev->net->stats.rx_length_errors++;
577 		netif_dbg(dev, rx_err, dev->net, "rx length %d\n", skb->len);
578 	} else {
579 		usbnet_skb_return(dev, skb);
580 		return;
581 	}
582 
583 done:
584 	skb_queue_tail(&dev->done, skb);
585 }
586 
587 /*-------------------------------------------------------------------------*/
588 
589 static void rx_complete (struct urb *urb)
590 {
591 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
592 	struct skb_data		*entry = (struct skb_data *) skb->cb;
593 	struct usbnet		*dev = entry->dev;
594 	int			urb_status = urb->status;
595 	enum skb_state		state;
596 
597 	skb_put (skb, urb->actual_length);
598 	state = rx_done;
599 	entry->urb = NULL;
600 
601 	switch (urb_status) {
602 	/* success */
603 	case 0:
604 		break;
605 
606 	/* stalls need manual reset. this is rare ... except that
607 	 * when going through USB 2.0 TTs, unplug appears this way.
608 	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
609 	 * storm, recovering as needed.
610 	 */
611 	case -EPIPE:
612 		dev->net->stats.rx_errors++;
613 		usbnet_defer_kevent (dev, EVENT_RX_HALT);
614 		fallthrough;
615 
616 	/* software-driven interface shutdown */
617 	case -ECONNRESET:		/* async unlink */
618 	case -ESHUTDOWN:		/* hardware gone */
619 		netif_dbg(dev, ifdown, dev->net,
620 			  "rx shutdown, code %d\n", urb_status);
621 		goto block;
622 
623 	/* we get controller i/o faults during hub_wq disconnect() delays.
624 	 * throttle down resubmits, to avoid log floods; just temporarily,
625 	 * so we still recover when the fault isn't a hub_wq delay.
626 	 */
627 	case -EPROTO:
628 	case -ETIME:
629 	case -EILSEQ:
630 		dev->net->stats.rx_errors++;
631 		if (!timer_pending (&dev->delay)) {
632 			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
633 			netif_dbg(dev, link, dev->net,
634 				  "rx throttle %d\n", urb_status);
635 		}
636 block:
637 		state = rx_cleanup;
638 		entry->urb = urb;
639 		urb = NULL;
640 		break;
641 
642 	/* data overrun ... flush fifo? */
643 	case -EOVERFLOW:
644 		dev->net->stats.rx_over_errors++;
645 		fallthrough;
646 
647 	default:
648 		state = rx_cleanup;
649 		dev->net->stats.rx_errors++;
650 		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
651 		break;
652 	}
653 
654 	/* stop rx if packet error rate is high */
655 	if (++dev->pkt_cnt > 30) {
656 		dev->pkt_cnt = 0;
657 		dev->pkt_err = 0;
658 	} else {
659 		if (state == rx_cleanup)
660 			dev->pkt_err++;
661 		if (dev->pkt_err > 20)
662 			set_bit(EVENT_RX_KILL, &dev->flags);
663 	}
664 
665 	state = defer_bh(dev, skb, &dev->rxq, state);
666 
667 	if (urb) {
668 		if (netif_running (dev->net) &&
669 		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
670 		    state != unlink_start) {
671 			rx_submit (dev, urb, GFP_ATOMIC);
672 			usb_mark_last_busy(dev->udev);
673 			return;
674 		}
675 		usb_free_urb (urb);
676 	}
677 	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
678 }
679 
680 /*-------------------------------------------------------------------------*/
681 void usbnet_pause_rx(struct usbnet *dev)
682 {
683 	set_bit(EVENT_RX_PAUSED, &dev->flags);
684 
685 	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
686 }
687 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
688 
689 void usbnet_resume_rx(struct usbnet *dev)
690 {
691 	struct sk_buff *skb;
692 	int num = 0;
693 
694 	clear_bit(EVENT_RX_PAUSED, &dev->flags);
695 
696 	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
697 		usbnet_skb_return(dev, skb);
698 		num++;
699 	}
700 
701 	tasklet_schedule(&dev->bh);
702 
703 	netif_dbg(dev, rx_status, dev->net,
704 		  "paused rx queue disabled, %d skbs requeued\n", num);
705 }
706 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
707 
708 void usbnet_purge_paused_rxq(struct usbnet *dev)
709 {
710 	skb_queue_purge(&dev->rxq_pause);
711 }
712 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
713 
714 /*-------------------------------------------------------------------------*/
715 
716 // unlink pending rx/tx; completion handlers do all other cleanup
717 
718 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
719 {
720 	unsigned long		flags;
721 	struct sk_buff		*skb;
722 	int			count = 0;
723 
724 	spin_lock_irqsave (&q->lock, flags);
725 	while (!skb_queue_empty(q)) {
726 		struct skb_data		*entry;
727 		struct urb		*urb;
728 		int			retval;
729 
730 		skb_queue_walk(q, skb) {
731 			entry = (struct skb_data *) skb->cb;
732 			if (entry->state != unlink_start)
733 				goto found;
734 		}
735 		break;
736 found:
737 		entry->state = unlink_start;
738 		urb = entry->urb;
739 
740 		/*
741 		 * Get reference count of the URB to avoid it to be
742 		 * freed during usb_unlink_urb, which may trigger
743 		 * use-after-free problem inside usb_unlink_urb since
744 		 * usb_unlink_urb is always racing with .complete
745 		 * handler(include defer_bh).
746 		 */
747 		usb_get_urb(urb);
748 		spin_unlock_irqrestore(&q->lock, flags);
749 		// during some PM-driven resume scenarios,
750 		// these (async) unlinks complete immediately
751 		retval = usb_unlink_urb (urb);
752 		if (retval != -EINPROGRESS && retval != 0)
753 			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
754 		else
755 			count++;
756 		usb_put_urb(urb);
757 		spin_lock_irqsave(&q->lock, flags);
758 	}
759 	spin_unlock_irqrestore (&q->lock, flags);
760 	return count;
761 }
762 
763 // Flush all pending rx urbs
764 // minidrivers may need to do this when the MTU changes
765 
766 void usbnet_unlink_rx_urbs(struct usbnet *dev)
767 {
768 	if (netif_running(dev->net)) {
769 		(void) unlink_urbs (dev, &dev->rxq);
770 		tasklet_schedule(&dev->bh);
771 	}
772 }
773 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
774 
775 /*-------------------------------------------------------------------------*/
776 
777 static void wait_skb_queue_empty(struct sk_buff_head *q)
778 {
779 	unsigned long flags;
780 
781 	spin_lock_irqsave(&q->lock, flags);
782 	while (!skb_queue_empty(q)) {
783 		spin_unlock_irqrestore(&q->lock, flags);
784 		schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
785 		set_current_state(TASK_UNINTERRUPTIBLE);
786 		spin_lock_irqsave(&q->lock, flags);
787 	}
788 	spin_unlock_irqrestore(&q->lock, flags);
789 }
790 
791 // precondition: never called in_interrupt
792 static void usbnet_terminate_urbs(struct usbnet *dev)
793 {
794 	DECLARE_WAITQUEUE(wait, current);
795 	int temp;
796 
797 	/* ensure there are no more active urbs */
798 	add_wait_queue(&dev->wait, &wait);
799 	set_current_state(TASK_UNINTERRUPTIBLE);
800 	temp = unlink_urbs(dev, &dev->txq) +
801 		unlink_urbs(dev, &dev->rxq);
802 
803 	/* maybe wait for deletions to finish. */
804 	wait_skb_queue_empty(&dev->rxq);
805 	wait_skb_queue_empty(&dev->txq);
806 	wait_skb_queue_empty(&dev->done);
807 	netif_dbg(dev, ifdown, dev->net,
808 		  "waited for %d urb completions\n", temp);
809 	set_current_state(TASK_RUNNING);
810 	remove_wait_queue(&dev->wait, &wait);
811 }
812 
813 int usbnet_stop (struct net_device *net)
814 {
815 	struct usbnet		*dev = netdev_priv(net);
816 	const struct driver_info *info = dev->driver_info;
817 	int			retval, pm, mpn;
818 
819 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
820 	netif_stop_queue (net);
821 
822 	netif_info(dev, ifdown, dev->net,
823 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
824 		   net->stats.rx_packets, net->stats.tx_packets,
825 		   net->stats.rx_errors, net->stats.tx_errors);
826 
827 	/* to not race resume */
828 	pm = usb_autopm_get_interface(dev->intf);
829 	/* allow minidriver to stop correctly (wireless devices to turn off
830 	 * radio etc) */
831 	if (info->stop) {
832 		retval = info->stop(dev);
833 		if (retval < 0)
834 			netif_info(dev, ifdown, dev->net,
835 				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
836 				   retval,
837 				   dev->udev->bus->bus_name, dev->udev->devpath,
838 				   info->description);
839 	}
840 
841 	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
842 		usbnet_terminate_urbs(dev);
843 
844 	usbnet_status_stop(dev);
845 
846 	usbnet_purge_paused_rxq(dev);
847 
848 	mpn = !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
849 
850 	/* deferred work (task, timer, softirq) must also stop.
851 	 * can't flush_scheduled_work() until we drop rtnl (later),
852 	 * else workers could deadlock; so make workers a NOP.
853 	 */
854 	dev->flags = 0;
855 	del_timer_sync (&dev->delay);
856 	tasklet_kill (&dev->bh);
857 	if (!pm)
858 		usb_autopm_put_interface(dev->intf);
859 
860 	if (info->manage_power && mpn)
861 		info->manage_power(dev, 0);
862 	else
863 		usb_autopm_put_interface(dev->intf);
864 
865 	return 0;
866 }
867 EXPORT_SYMBOL_GPL(usbnet_stop);
868 
869 /*-------------------------------------------------------------------------*/
870 
871 // posts reads, and enables write queuing
872 
873 // precondition: never called in_interrupt
874 
875 int usbnet_open (struct net_device *net)
876 {
877 	struct usbnet		*dev = netdev_priv(net);
878 	int			retval;
879 	const struct driver_info *info = dev->driver_info;
880 
881 	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
882 		netif_info(dev, ifup, dev->net,
883 			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
884 			   retval,
885 			   dev->udev->bus->bus_name,
886 			   dev->udev->devpath,
887 			   info->description);
888 		goto done_nopm;
889 	}
890 
891 	// put into "known safe" state
892 	if (info->reset && (retval = info->reset (dev)) < 0) {
893 		netif_info(dev, ifup, dev->net,
894 			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
895 			   retval,
896 			   dev->udev->bus->bus_name,
897 			   dev->udev->devpath,
898 			   info->description);
899 		goto done;
900 	}
901 
902 	/* hard_mtu or rx_urb_size may change in reset() */
903 	usbnet_update_max_qlen(dev);
904 
905 	// insist peer be connected
906 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
907 		netif_err(dev, ifup, dev->net, "can't open; %d\n", retval);
908 		goto done;
909 	}
910 
911 	/* start any status interrupt transfer */
912 	if (dev->interrupt) {
913 		retval = usbnet_status_start(dev, GFP_KERNEL);
914 		if (retval < 0) {
915 			netif_err(dev, ifup, dev->net,
916 				  "intr submit %d\n", retval);
917 			goto done;
918 		}
919 	}
920 
921 	set_bit(EVENT_DEV_OPEN, &dev->flags);
922 	netif_start_queue (net);
923 	netif_info(dev, ifup, dev->net,
924 		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
925 		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
926 		   dev->net->mtu,
927 		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
928 		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
929 		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
930 		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
931 		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
932 		   "simple");
933 
934 	/* reset rx error state */
935 	dev->pkt_cnt = 0;
936 	dev->pkt_err = 0;
937 	clear_bit(EVENT_RX_KILL, &dev->flags);
938 
939 	// delay posting reads until we're fully open
940 	tasklet_schedule (&dev->bh);
941 	if (info->manage_power) {
942 		retval = info->manage_power(dev, 1);
943 		if (retval < 0) {
944 			retval = 0;
945 			set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
946 		} else {
947 			usb_autopm_put_interface(dev->intf);
948 		}
949 	}
950 	return retval;
951 done:
952 	usb_autopm_put_interface(dev->intf);
953 done_nopm:
954 	return retval;
955 }
956 EXPORT_SYMBOL_GPL(usbnet_open);
957 
958 /*-------------------------------------------------------------------------*/
959 
960 /* ethtool methods; minidrivers may need to add some more, but
961  * they'll probably want to use this base set.
962  */
963 
964 /* These methods are written on the assumption that the device
965  * uses MII
966  */
967 int usbnet_get_link_ksettings_mii(struct net_device *net,
968 			      struct ethtool_link_ksettings *cmd)
969 {
970 	struct usbnet *dev = netdev_priv(net);
971 
972 	if (!dev->mii.mdio_read)
973 		return -EOPNOTSUPP;
974 
975 	mii_ethtool_get_link_ksettings(&dev->mii, cmd);
976 
977 	return 0;
978 }
979 EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings_mii);
980 
981 int usbnet_get_link_ksettings_internal(struct net_device *net,
982 					struct ethtool_link_ksettings *cmd)
983 {
984 	struct usbnet *dev = netdev_priv(net);
985 
986 	/* the assumption that speed is equal on tx and rx
987 	 * is deeply engrained into the networking layer.
988 	 * For wireless stuff it is not true.
989 	 * We assume that rx_speed matters more.
990 	 */
991 	if (dev->rx_speed != SPEED_UNSET)
992 		cmd->base.speed = dev->rx_speed / 1000000;
993 	else if (dev->tx_speed != SPEED_UNSET)
994 		cmd->base.speed = dev->tx_speed / 1000000;
995 	else
996 		cmd->base.speed = SPEED_UNKNOWN;
997 
998 	return 0;
999 }
1000 EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings_internal);
1001 
1002 int usbnet_set_link_ksettings_mii(struct net_device *net,
1003 			      const struct ethtool_link_ksettings *cmd)
1004 {
1005 	struct usbnet *dev = netdev_priv(net);
1006 	int retval;
1007 
1008 	if (!dev->mii.mdio_write)
1009 		return -EOPNOTSUPP;
1010 
1011 	retval = mii_ethtool_set_link_ksettings(&dev->mii, cmd);
1012 
1013 	/* link speed/duplex might have changed */
1014 	if (dev->driver_info->link_reset)
1015 		dev->driver_info->link_reset(dev);
1016 
1017 	/* hard_mtu or rx_urb_size may change in link_reset() */
1018 	usbnet_update_max_qlen(dev);
1019 
1020 	return retval;
1021 }
1022 EXPORT_SYMBOL_GPL(usbnet_set_link_ksettings_mii);
1023 
1024 u32 usbnet_get_link (struct net_device *net)
1025 {
1026 	struct usbnet *dev = netdev_priv(net);
1027 
1028 	/* If a check_connect is defined, return its result */
1029 	if (dev->driver_info->check_connect)
1030 		return dev->driver_info->check_connect (dev) == 0;
1031 
1032 	/* if the device has mii operations, use those */
1033 	if (dev->mii.mdio_read)
1034 		return mii_link_ok(&dev->mii);
1035 
1036 	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
1037 	return ethtool_op_get_link(net);
1038 }
1039 EXPORT_SYMBOL_GPL(usbnet_get_link);
1040 
1041 int usbnet_nway_reset(struct net_device *net)
1042 {
1043 	struct usbnet *dev = netdev_priv(net);
1044 
1045 	if (!dev->mii.mdio_write)
1046 		return -EOPNOTSUPP;
1047 
1048 	return mii_nway_restart(&dev->mii);
1049 }
1050 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
1051 
1052 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
1053 {
1054 	struct usbnet *dev = netdev_priv(net);
1055 
1056 	strlcpy (info->driver, dev->driver_name, sizeof info->driver);
1057 	strlcpy (info->fw_version, dev->driver_info->description,
1058 		sizeof info->fw_version);
1059 	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
1060 }
1061 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
1062 
1063 u32 usbnet_get_msglevel (struct net_device *net)
1064 {
1065 	struct usbnet *dev = netdev_priv(net);
1066 
1067 	return dev->msg_enable;
1068 }
1069 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
1070 
1071 void usbnet_set_msglevel (struct net_device *net, u32 level)
1072 {
1073 	struct usbnet *dev = netdev_priv(net);
1074 
1075 	dev->msg_enable = level;
1076 }
1077 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
1078 
1079 /* drivers may override default ethtool_ops in their bind() routine */
1080 static const struct ethtool_ops usbnet_ethtool_ops = {
1081 	.get_link		= usbnet_get_link,
1082 	.nway_reset		= usbnet_nway_reset,
1083 	.get_drvinfo		= usbnet_get_drvinfo,
1084 	.get_msglevel		= usbnet_get_msglevel,
1085 	.set_msglevel		= usbnet_set_msglevel,
1086 	.get_ts_info		= ethtool_op_get_ts_info,
1087 	.get_link_ksettings	= usbnet_get_link_ksettings_mii,
1088 	.set_link_ksettings	= usbnet_set_link_ksettings_mii,
1089 };
1090 
1091 /*-------------------------------------------------------------------------*/
1092 
1093 static void __handle_link_change(struct usbnet *dev)
1094 {
1095 	if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
1096 		return;
1097 
1098 	if (!netif_carrier_ok(dev->net)) {
1099 		/* kill URBs for reading packets to save bus bandwidth */
1100 		unlink_urbs(dev, &dev->rxq);
1101 
1102 		/*
1103 		 * tx_timeout will unlink URBs for sending packets and
1104 		 * tx queue is stopped by netcore after link becomes off
1105 		 */
1106 	} else {
1107 		/* submitting URBs for reading packets */
1108 		tasklet_schedule(&dev->bh);
1109 	}
1110 
1111 	/* hard_mtu or rx_urb_size may change during link change */
1112 	usbnet_update_max_qlen(dev);
1113 
1114 	clear_bit(EVENT_LINK_CHANGE, &dev->flags);
1115 }
1116 
1117 void usbnet_set_rx_mode(struct net_device *net)
1118 {
1119 	struct usbnet		*dev = netdev_priv(net);
1120 
1121 	usbnet_defer_kevent(dev, EVENT_SET_RX_MODE);
1122 }
1123 EXPORT_SYMBOL_GPL(usbnet_set_rx_mode);
1124 
1125 static void __handle_set_rx_mode(struct usbnet *dev)
1126 {
1127 	if (dev->driver_info->set_rx_mode)
1128 		(dev->driver_info->set_rx_mode)(dev);
1129 
1130 	clear_bit(EVENT_SET_RX_MODE, &dev->flags);
1131 }
1132 
1133 /* work that cannot be done in interrupt context uses keventd.
1134  *
1135  * NOTE:  with 2.5 we could do more of this using completion callbacks,
1136  * especially now that control transfers can be queued.
1137  */
1138 static void
1139 usbnet_deferred_kevent (struct work_struct *work)
1140 {
1141 	struct usbnet		*dev =
1142 		container_of(work, struct usbnet, kevent);
1143 	int			status;
1144 
1145 	/* usb_clear_halt() needs a thread context */
1146 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
1147 		unlink_urbs (dev, &dev->txq);
1148 		status = usb_autopm_get_interface(dev->intf);
1149 		if (status < 0)
1150 			goto fail_pipe;
1151 		status = usb_clear_halt (dev->udev, dev->out);
1152 		usb_autopm_put_interface(dev->intf);
1153 		if (status < 0 &&
1154 		    status != -EPIPE &&
1155 		    status != -ESHUTDOWN) {
1156 			if (netif_msg_tx_err (dev))
1157 fail_pipe:
1158 				netdev_err(dev->net, "can't clear tx halt, status %d\n",
1159 					   status);
1160 		} else {
1161 			clear_bit (EVENT_TX_HALT, &dev->flags);
1162 			if (status != -ESHUTDOWN)
1163 				netif_wake_queue (dev->net);
1164 		}
1165 	}
1166 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
1167 		unlink_urbs (dev, &dev->rxq);
1168 		status = usb_autopm_get_interface(dev->intf);
1169 		if (status < 0)
1170 			goto fail_halt;
1171 		status = usb_clear_halt (dev->udev, dev->in);
1172 		usb_autopm_put_interface(dev->intf);
1173 		if (status < 0 &&
1174 		    status != -EPIPE &&
1175 		    status != -ESHUTDOWN) {
1176 			if (netif_msg_rx_err (dev))
1177 fail_halt:
1178 				netdev_err(dev->net, "can't clear rx halt, status %d\n",
1179 					   status);
1180 		} else {
1181 			clear_bit (EVENT_RX_HALT, &dev->flags);
1182 			tasklet_schedule (&dev->bh);
1183 		}
1184 	}
1185 
1186 	/* tasklet could resubmit itself forever if memory is tight */
1187 	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
1188 		struct urb	*urb = NULL;
1189 		int resched = 1;
1190 
1191 		if (netif_running (dev->net))
1192 			urb = usb_alloc_urb (0, GFP_KERNEL);
1193 		else
1194 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1195 		if (urb != NULL) {
1196 			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1197 			status = usb_autopm_get_interface(dev->intf);
1198 			if (status < 0) {
1199 				usb_free_urb(urb);
1200 				goto fail_lowmem;
1201 			}
1202 			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
1203 				resched = 0;
1204 			usb_autopm_put_interface(dev->intf);
1205 fail_lowmem:
1206 			if (resched)
1207 				tasklet_schedule (&dev->bh);
1208 		}
1209 	}
1210 
1211 	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
1212 		const struct driver_info *info = dev->driver_info;
1213 		int			retval = 0;
1214 
1215 		clear_bit (EVENT_LINK_RESET, &dev->flags);
1216 		status = usb_autopm_get_interface(dev->intf);
1217 		if (status < 0)
1218 			goto skip_reset;
1219 		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1220 			usb_autopm_put_interface(dev->intf);
1221 skip_reset:
1222 			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1223 				    retval,
1224 				    dev->udev->bus->bus_name,
1225 				    dev->udev->devpath,
1226 				    info->description);
1227 		} else {
1228 			usb_autopm_put_interface(dev->intf);
1229 		}
1230 
1231 		/* handle link change from link resetting */
1232 		__handle_link_change(dev);
1233 	}
1234 
1235 	if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
1236 		__handle_link_change(dev);
1237 
1238 	if (test_bit (EVENT_SET_RX_MODE, &dev->flags))
1239 		__handle_set_rx_mode(dev);
1240 
1241 
1242 	if (dev->flags)
1243 		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1244 }
1245 
1246 /*-------------------------------------------------------------------------*/
1247 
1248 static void tx_complete (struct urb *urb)
1249 {
1250 	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1251 	struct skb_data		*entry = (struct skb_data *) skb->cb;
1252 	struct usbnet		*dev = entry->dev;
1253 
1254 	if (urb->status == 0) {
1255 		struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->net->tstats);
1256 		unsigned long flags;
1257 
1258 		flags = u64_stats_update_begin_irqsave(&stats64->syncp);
1259 		stats64->tx_packets += entry->packets;
1260 		stats64->tx_bytes += entry->length;
1261 		u64_stats_update_end_irqrestore(&stats64->syncp, flags);
1262 	} else {
1263 		dev->net->stats.tx_errors++;
1264 
1265 		switch (urb->status) {
1266 		case -EPIPE:
1267 			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1268 			break;
1269 
1270 		/* software-driven interface shutdown */
1271 		case -ECONNRESET:		// async unlink
1272 		case -ESHUTDOWN:		// hardware gone
1273 			break;
1274 
1275 		/* like rx, tx gets controller i/o faults during hub_wq
1276 		 * delays and so it uses the same throttling mechanism.
1277 		 */
1278 		case -EPROTO:
1279 		case -ETIME:
1280 		case -EILSEQ:
1281 			usb_mark_last_busy(dev->udev);
1282 			if (!timer_pending (&dev->delay)) {
1283 				mod_timer (&dev->delay,
1284 					jiffies + THROTTLE_JIFFIES);
1285 				netif_dbg(dev, link, dev->net,
1286 					  "tx throttle %d\n", urb->status);
1287 			}
1288 			netif_stop_queue (dev->net);
1289 			break;
1290 		default:
1291 			netif_dbg(dev, tx_err, dev->net,
1292 				  "tx err %d\n", entry->urb->status);
1293 			break;
1294 		}
1295 	}
1296 
1297 	usb_autopm_put_interface_async(dev->intf);
1298 	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1299 }
1300 
1301 /*-------------------------------------------------------------------------*/
1302 
1303 void usbnet_tx_timeout (struct net_device *net, unsigned int txqueue)
1304 {
1305 	struct usbnet		*dev = netdev_priv(net);
1306 
1307 	unlink_urbs (dev, &dev->txq);
1308 	tasklet_schedule (&dev->bh);
1309 	/* this needs to be handled individually because the generic layer
1310 	 * doesn't know what is sufficient and could not restore private
1311 	 * information if a remedy of an unconditional reset were used.
1312 	 */
1313 	if (dev->driver_info->recover)
1314 		(dev->driver_info->recover)(dev);
1315 }
1316 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1317 
1318 /*-------------------------------------------------------------------------*/
1319 
1320 static int build_dma_sg(const struct sk_buff *skb, struct urb *urb)
1321 {
1322 	unsigned num_sgs, total_len = 0;
1323 	int i, s = 0;
1324 
1325 	num_sgs = skb_shinfo(skb)->nr_frags + 1;
1326 	if (num_sgs == 1)
1327 		return 0;
1328 
1329 	/* reserve one for zero packet */
1330 	urb->sg = kmalloc_array(num_sgs + 1, sizeof(struct scatterlist),
1331 				GFP_ATOMIC);
1332 	if (!urb->sg)
1333 		return -ENOMEM;
1334 
1335 	urb->num_sgs = num_sgs;
1336 	sg_init_table(urb->sg, urb->num_sgs + 1);
1337 
1338 	sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb));
1339 	total_len += skb_headlen(skb);
1340 
1341 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1342 		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
1343 
1344 		total_len += skb_frag_size(f);
1345 		sg_set_page(&urb->sg[i + s], skb_frag_page(f), skb_frag_size(f),
1346 			    skb_frag_off(f));
1347 	}
1348 	urb->transfer_buffer_length = total_len;
1349 
1350 	return 1;
1351 }
1352 
1353 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1354 				     struct net_device *net)
1355 {
1356 	struct usbnet		*dev = netdev_priv(net);
1357 	unsigned int			length;
1358 	struct urb		*urb = NULL;
1359 	struct skb_data		*entry;
1360 	const struct driver_info *info = dev->driver_info;
1361 	unsigned long		flags;
1362 	int retval;
1363 
1364 	if (skb)
1365 		skb_tx_timestamp(skb);
1366 
1367 	// some devices want funky USB-level framing, for
1368 	// win32 driver (usually) and/or hardware quirks
1369 	if (info->tx_fixup) {
1370 		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1371 		if (!skb) {
1372 			/* packet collected; minidriver waiting for more */
1373 			if (info->flags & FLAG_MULTI_PACKET)
1374 				goto not_drop;
1375 			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1376 			goto drop;
1377 		}
1378 	}
1379 
1380 	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1381 		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1382 		goto drop;
1383 	}
1384 
1385 	entry = (struct skb_data *) skb->cb;
1386 	entry->urb = urb;
1387 	entry->dev = dev;
1388 
1389 	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1390 			skb->data, skb->len, tx_complete, skb);
1391 	if (dev->can_dma_sg) {
1392 		if (build_dma_sg(skb, urb) < 0)
1393 			goto drop;
1394 	}
1395 	length = urb->transfer_buffer_length;
1396 
1397 	/* don't assume the hardware handles USB_ZERO_PACKET
1398 	 * NOTE:  strictly conforming cdc-ether devices should expect
1399 	 * the ZLP here, but ignore the one-byte packet.
1400 	 * NOTE2: CDC NCM specification is different from CDC ECM when
1401 	 * handling ZLP/short packets, so cdc_ncm driver will make short
1402 	 * packet itself if needed.
1403 	 */
1404 	if (length % dev->maxpacket == 0) {
1405 		if (!(info->flags & FLAG_SEND_ZLP)) {
1406 			if (!(info->flags & FLAG_MULTI_PACKET)) {
1407 				length++;
1408 				if (skb_tailroom(skb) && !urb->num_sgs) {
1409 					skb->data[skb->len] = 0;
1410 					__skb_put(skb, 1);
1411 				} else if (urb->num_sgs)
1412 					sg_set_buf(&urb->sg[urb->num_sgs++],
1413 							dev->padding_pkt, 1);
1414 			}
1415 		} else
1416 			urb->transfer_flags |= URB_ZERO_PACKET;
1417 	}
1418 	urb->transfer_buffer_length = length;
1419 
1420 	if (info->flags & FLAG_MULTI_PACKET) {
1421 		/* Driver has set number of packets and a length delta.
1422 		 * Calculate the complete length and ensure that it's
1423 		 * positive.
1424 		 */
1425 		entry->length += length;
1426 		if (WARN_ON_ONCE(entry->length <= 0))
1427 			entry->length = length;
1428 	} else {
1429 		usbnet_set_skb_tx_stats(skb, 1, length);
1430 	}
1431 
1432 	spin_lock_irqsave(&dev->txq.lock, flags);
1433 	retval = usb_autopm_get_interface_async(dev->intf);
1434 	if (retval < 0) {
1435 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1436 		goto drop;
1437 	}
1438 	if (netif_queue_stopped(net)) {
1439 		usb_autopm_put_interface_async(dev->intf);
1440 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1441 		goto drop;
1442 	}
1443 
1444 #ifdef CONFIG_PM
1445 	/* if this triggers the device is still a sleep */
1446 	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1447 		/* transmission will be done in resume */
1448 		usb_anchor_urb(urb, &dev->deferred);
1449 		/* no use to process more packets */
1450 		netif_stop_queue(net);
1451 		usb_put_urb(urb);
1452 		spin_unlock_irqrestore(&dev->txq.lock, flags);
1453 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1454 		goto deferred;
1455 	}
1456 #endif
1457 
1458 	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1459 	case -EPIPE:
1460 		netif_stop_queue (net);
1461 		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1462 		usb_autopm_put_interface_async(dev->intf);
1463 		break;
1464 	default:
1465 		usb_autopm_put_interface_async(dev->intf);
1466 		netif_dbg(dev, tx_err, dev->net,
1467 			  "tx: submit urb err %d\n", retval);
1468 		break;
1469 	case 0:
1470 		netif_trans_update(net);
1471 		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1472 		if (dev->txq.qlen >= TX_QLEN (dev))
1473 			netif_stop_queue (net);
1474 	}
1475 	spin_unlock_irqrestore (&dev->txq.lock, flags);
1476 
1477 	if (retval) {
1478 		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1479 drop:
1480 		dev->net->stats.tx_dropped++;
1481 not_drop:
1482 		if (skb)
1483 			dev_kfree_skb_any (skb);
1484 		if (urb) {
1485 			kfree(urb->sg);
1486 			usb_free_urb(urb);
1487 		}
1488 	} else
1489 		netif_dbg(dev, tx_queued, dev->net,
1490 			  "> tx, len %u, type 0x%x\n", length, skb->protocol);
1491 #ifdef CONFIG_PM
1492 deferred:
1493 #endif
1494 	return NETDEV_TX_OK;
1495 }
1496 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1497 
1498 static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1499 {
1500 	struct urb	*urb;
1501 	int		i;
1502 	int		ret = 0;
1503 
1504 	/* don't refill the queue all at once */
1505 	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1506 		urb = usb_alloc_urb(0, flags);
1507 		if (urb != NULL) {
1508 			ret = rx_submit(dev, urb, flags);
1509 			if (ret)
1510 				goto err;
1511 		} else {
1512 			ret = -ENOMEM;
1513 			goto err;
1514 		}
1515 	}
1516 err:
1517 	return ret;
1518 }
1519 
1520 /*-------------------------------------------------------------------------*/
1521 
1522 // tasklet (work deferred from completions, in_irq) or timer
1523 
1524 static void usbnet_bh (struct timer_list *t)
1525 {
1526 	struct usbnet		*dev = from_timer(dev, t, delay);
1527 	struct sk_buff		*skb;
1528 	struct skb_data		*entry;
1529 
1530 	while ((skb = skb_dequeue (&dev->done))) {
1531 		entry = (struct skb_data *) skb->cb;
1532 		switch (entry->state) {
1533 		case rx_done:
1534 			entry->state = rx_cleanup;
1535 			rx_process (dev, skb);
1536 			continue;
1537 		case tx_done:
1538 			kfree(entry->urb->sg);
1539 			fallthrough;
1540 		case rx_cleanup:
1541 			usb_free_urb (entry->urb);
1542 			dev_kfree_skb (skb);
1543 			continue;
1544 		default:
1545 			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1546 		}
1547 	}
1548 
1549 	/* restart RX again after disabling due to high error rate */
1550 	clear_bit(EVENT_RX_KILL, &dev->flags);
1551 
1552 	/* waiting for all pending urbs to complete?
1553 	 * only then can we forgo submitting anew
1554 	 */
1555 	if (waitqueue_active(&dev->wait)) {
1556 		if (dev->txq.qlen + dev->rxq.qlen + dev->done.qlen == 0)
1557 			wake_up_all(&dev->wait);
1558 
1559 	// or are we maybe short a few urbs?
1560 	} else if (netif_running (dev->net) &&
1561 		   netif_device_present (dev->net) &&
1562 		   netif_carrier_ok(dev->net) &&
1563 		   !timer_pending(&dev->delay) &&
1564 		   !test_bit(EVENT_RX_PAUSED, &dev->flags) &&
1565 		   !test_bit(EVENT_RX_HALT, &dev->flags)) {
1566 		int	temp = dev->rxq.qlen;
1567 
1568 		if (temp < RX_QLEN(dev)) {
1569 			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1570 				return;
1571 			if (temp != dev->rxq.qlen)
1572 				netif_dbg(dev, link, dev->net,
1573 					  "rxqlen %d --> %d\n",
1574 					  temp, dev->rxq.qlen);
1575 			if (dev->rxq.qlen < RX_QLEN(dev))
1576 				tasklet_schedule (&dev->bh);
1577 		}
1578 		if (dev->txq.qlen < TX_QLEN (dev))
1579 			netif_wake_queue (dev->net);
1580 	}
1581 }
1582 
1583 static void usbnet_bh_tasklet(struct tasklet_struct *t)
1584 {
1585 	struct usbnet *dev = from_tasklet(dev, t, bh);
1586 
1587 	usbnet_bh(&dev->delay);
1588 }
1589 
1590 
1591 /*-------------------------------------------------------------------------
1592  *
1593  * USB Device Driver support
1594  *
1595  *-------------------------------------------------------------------------*/
1596 
1597 // precondition: never called in_interrupt
1598 
1599 void usbnet_disconnect (struct usb_interface *intf)
1600 {
1601 	struct usbnet		*dev;
1602 	struct usb_device	*xdev;
1603 	struct net_device	*net;
1604 
1605 	dev = usb_get_intfdata(intf);
1606 	usb_set_intfdata(intf, NULL);
1607 	if (!dev)
1608 		return;
1609 
1610 	xdev = interface_to_usbdev (intf);
1611 
1612 	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1613 		   intf->dev.driver->name,
1614 		   xdev->bus->bus_name, xdev->devpath,
1615 		   dev->driver_info->description);
1616 
1617 	if (dev->driver_info->unbind)
1618 		dev->driver_info->unbind(dev, intf);
1619 
1620 	net = dev->net;
1621 	unregister_netdev (net);
1622 
1623 	cancel_work_sync(&dev->kevent);
1624 
1625 	usb_scuttle_anchored_urbs(&dev->deferred);
1626 
1627 	usb_kill_urb(dev->interrupt);
1628 	usb_free_urb(dev->interrupt);
1629 	kfree(dev->padding_pkt);
1630 
1631 	free_percpu(net->tstats);
1632 	free_netdev(net);
1633 }
1634 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1635 
1636 static const struct net_device_ops usbnet_netdev_ops = {
1637 	.ndo_open		= usbnet_open,
1638 	.ndo_stop		= usbnet_stop,
1639 	.ndo_start_xmit		= usbnet_start_xmit,
1640 	.ndo_tx_timeout		= usbnet_tx_timeout,
1641 	.ndo_set_rx_mode	= usbnet_set_rx_mode,
1642 	.ndo_change_mtu		= usbnet_change_mtu,
1643 	.ndo_get_stats64	= dev_get_tstats64,
1644 	.ndo_set_mac_address 	= eth_mac_addr,
1645 	.ndo_validate_addr	= eth_validate_addr,
1646 };
1647 
1648 /*-------------------------------------------------------------------------*/
1649 
1650 // precondition: never called in_interrupt
1651 
1652 static struct device_type wlan_type = {
1653 	.name	= "wlan",
1654 };
1655 
1656 static struct device_type wwan_type = {
1657 	.name	= "wwan",
1658 };
1659 
1660 int
1661 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1662 {
1663 	struct usbnet			*dev;
1664 	struct net_device		*net;
1665 	struct usb_host_interface	*interface;
1666 	const struct driver_info	*info;
1667 	struct usb_device		*xdev;
1668 	int				status;
1669 	const char			*name;
1670 	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1671 
1672 	/* usbnet already took usb runtime pm, so have to enable the feature
1673 	 * for usb interface, otherwise usb_autopm_get_interface may return
1674 	 * failure if RUNTIME_PM is enabled.
1675 	 */
1676 	if (!driver->supports_autosuspend) {
1677 		driver->supports_autosuspend = 1;
1678 		pm_runtime_enable(&udev->dev);
1679 	}
1680 
1681 	name = udev->dev.driver->name;
1682 	info = (const struct driver_info *) prod->driver_info;
1683 	if (!info) {
1684 		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1685 		return -ENODEV;
1686 	}
1687 	xdev = interface_to_usbdev (udev);
1688 	interface = udev->cur_altsetting;
1689 
1690 	status = -ENOMEM;
1691 
1692 	// set up our own records
1693 	net = alloc_etherdev(sizeof(*dev));
1694 	if (!net)
1695 		goto out;
1696 
1697 	/* netdev_printk() needs this so do it as early as possible */
1698 	SET_NETDEV_DEV(net, &udev->dev);
1699 
1700 	dev = netdev_priv(net);
1701 	dev->udev = xdev;
1702 	dev->intf = udev;
1703 	dev->driver_info = info;
1704 	dev->driver_name = name;
1705 	dev->rx_speed = SPEED_UNSET;
1706 	dev->tx_speed = SPEED_UNSET;
1707 
1708 	net->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1709 	if (!net->tstats)
1710 		goto out0;
1711 
1712 	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1713 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1714 	init_waitqueue_head(&dev->wait);
1715 	skb_queue_head_init (&dev->rxq);
1716 	skb_queue_head_init (&dev->txq);
1717 	skb_queue_head_init (&dev->done);
1718 	skb_queue_head_init(&dev->rxq_pause);
1719 	tasklet_setup(&dev->bh, usbnet_bh_tasklet);
1720 	INIT_WORK (&dev->kevent, usbnet_deferred_kevent);
1721 	init_usb_anchor(&dev->deferred);
1722 	timer_setup(&dev->delay, usbnet_bh, 0);
1723 	mutex_init (&dev->phy_mutex);
1724 	mutex_init(&dev->interrupt_mutex);
1725 	dev->interrupt_count = 0;
1726 
1727 	dev->net = net;
1728 	strcpy (net->name, "usb%d");
1729 	memcpy (net->dev_addr, node_id, sizeof node_id);
1730 
1731 	/* rx and tx sides can use different message sizes;
1732 	 * bind() should set rx_urb_size in that case.
1733 	 */
1734 	dev->hard_mtu = net->mtu + net->hard_header_len;
1735 	net->min_mtu = 0;
1736 	net->max_mtu = ETH_MAX_MTU;
1737 
1738 	net->netdev_ops = &usbnet_netdev_ops;
1739 	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1740 	net->ethtool_ops = &usbnet_ethtool_ops;
1741 
1742 	// allow device-specific bind/init procedures
1743 	// NOTE net->name still not usable ...
1744 	if (info->bind) {
1745 		status = info->bind (dev, udev);
1746 		if (status < 0)
1747 			goto out1;
1748 
1749 		// heuristic:  "usb%d" for links we know are two-host,
1750 		// else "eth%d" when there's reasonable doubt.  userspace
1751 		// can rename the link if it knows better.
1752 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1753 		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1754 		     (net->dev_addr [0] & 0x02) == 0))
1755 			strcpy (net->name, "eth%d");
1756 		/* WLAN devices should always be named "wlan%d" */
1757 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1758 			strcpy(net->name, "wlan%d");
1759 		/* WWAN devices should always be named "wwan%d" */
1760 		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1761 			strcpy(net->name, "wwan%d");
1762 
1763 		/* devices that cannot do ARP */
1764 		if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1765 			net->flags |= IFF_NOARP;
1766 
1767 		/* maybe the remote can't receive an Ethernet MTU */
1768 		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1769 			net->mtu = dev->hard_mtu - net->hard_header_len;
1770 	} else if (!info->in || !info->out)
1771 		status = usbnet_get_endpoints (dev, udev);
1772 	else {
1773 		dev->in = usb_rcvbulkpipe (xdev, info->in);
1774 		dev->out = usb_sndbulkpipe (xdev, info->out);
1775 		if (!(info->flags & FLAG_NO_SETINT))
1776 			status = usb_set_interface (xdev,
1777 				interface->desc.bInterfaceNumber,
1778 				interface->desc.bAlternateSetting);
1779 		else
1780 			status = 0;
1781 
1782 	}
1783 	if (status >= 0 && dev->status)
1784 		status = init_status (dev, udev);
1785 	if (status < 0)
1786 		goto out3;
1787 
1788 	if (!dev->rx_urb_size)
1789 		dev->rx_urb_size = dev->hard_mtu;
1790 	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1791 
1792 	/* let userspace know we have a random address */
1793 	if (ether_addr_equal(net->dev_addr, node_id))
1794 		net->addr_assign_type = NET_ADDR_RANDOM;
1795 
1796 	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1797 		SET_NETDEV_DEVTYPE(net, &wlan_type);
1798 	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1799 		SET_NETDEV_DEVTYPE(net, &wwan_type);
1800 
1801 	/* initialize max rx_qlen and tx_qlen */
1802 	usbnet_update_max_qlen(dev);
1803 
1804 	if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&
1805 		!(info->flags & FLAG_MULTI_PACKET)) {
1806 		dev->padding_pkt = kzalloc(1, GFP_KERNEL);
1807 		if (!dev->padding_pkt) {
1808 			status = -ENOMEM;
1809 			goto out4;
1810 		}
1811 	}
1812 
1813 	status = register_netdev (net);
1814 	if (status)
1815 		goto out5;
1816 	netif_info(dev, probe, dev->net,
1817 		   "register '%s' at usb-%s-%s, %s, %pM\n",
1818 		   udev->dev.driver->name,
1819 		   xdev->bus->bus_name, xdev->devpath,
1820 		   dev->driver_info->description,
1821 		   net->dev_addr);
1822 
1823 	// ok, it's ready to go.
1824 	usb_set_intfdata (udev, dev);
1825 
1826 	netif_device_attach (net);
1827 
1828 	if (dev->driver_info->flags & FLAG_LINK_INTR)
1829 		usbnet_link_change(dev, 0, 0);
1830 
1831 	return 0;
1832 
1833 out5:
1834 	kfree(dev->padding_pkt);
1835 out4:
1836 	usb_free_urb(dev->interrupt);
1837 out3:
1838 	if (info->unbind)
1839 		info->unbind (dev, udev);
1840 out1:
1841 	/* subdrivers must undo all they did in bind() if they
1842 	 * fail it, but we may fail later and a deferred kevent
1843 	 * may trigger an error resubmitting itself and, worse,
1844 	 * schedule a timer. So we kill it all just in case.
1845 	 */
1846 	cancel_work_sync(&dev->kevent);
1847 	del_timer_sync(&dev->delay);
1848 	free_percpu(net->tstats);
1849 out0:
1850 	free_netdev(net);
1851 out:
1852 	return status;
1853 }
1854 EXPORT_SYMBOL_GPL(usbnet_probe);
1855 
1856 /*-------------------------------------------------------------------------*/
1857 
1858 /*
1859  * suspend the whole driver as soon as the first interface is suspended
1860  * resume only when the last interface is resumed
1861  */
1862 
1863 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1864 {
1865 	struct usbnet		*dev = usb_get_intfdata(intf);
1866 
1867 	if (!dev->suspend_count++) {
1868 		spin_lock_irq(&dev->txq.lock);
1869 		/* don't autosuspend while transmitting */
1870 		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1871 			dev->suspend_count--;
1872 			spin_unlock_irq(&dev->txq.lock);
1873 			return -EBUSY;
1874 		} else {
1875 			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1876 			spin_unlock_irq(&dev->txq.lock);
1877 		}
1878 		/*
1879 		 * accelerate emptying of the rx and queues, to avoid
1880 		 * having everything error out.
1881 		 */
1882 		netif_device_detach (dev->net);
1883 		usbnet_terminate_urbs(dev);
1884 		__usbnet_status_stop_force(dev);
1885 
1886 		/*
1887 		 * reattach so runtime management can use and
1888 		 * wake the device
1889 		 */
1890 		netif_device_attach (dev->net);
1891 	}
1892 	return 0;
1893 }
1894 EXPORT_SYMBOL_GPL(usbnet_suspend);
1895 
1896 int usbnet_resume (struct usb_interface *intf)
1897 {
1898 	struct usbnet		*dev = usb_get_intfdata(intf);
1899 	struct sk_buff          *skb;
1900 	struct urb              *res;
1901 	int                     retval;
1902 
1903 	if (!--dev->suspend_count) {
1904 		/* resume interrupt URB if it was previously submitted */
1905 		__usbnet_status_start_force(dev, GFP_NOIO);
1906 
1907 		spin_lock_irq(&dev->txq.lock);
1908 		while ((res = usb_get_from_anchor(&dev->deferred))) {
1909 
1910 			skb = (struct sk_buff *)res->context;
1911 			retval = usb_submit_urb(res, GFP_ATOMIC);
1912 			if (retval < 0) {
1913 				dev_kfree_skb_any(skb);
1914 				kfree(res->sg);
1915 				usb_free_urb(res);
1916 				usb_autopm_put_interface_async(dev->intf);
1917 			} else {
1918 				netif_trans_update(dev->net);
1919 				__skb_queue_tail(&dev->txq, skb);
1920 			}
1921 		}
1922 
1923 		smp_mb();
1924 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1925 		spin_unlock_irq(&dev->txq.lock);
1926 
1927 		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1928 			/* handle remote wakeup ASAP
1929 			 * we cannot race against stop
1930 			 */
1931 			if (netif_device_present(dev->net) &&
1932 				!timer_pending(&dev->delay) &&
1933 				!test_bit(EVENT_RX_HALT, &dev->flags))
1934 					rx_alloc_submit(dev, GFP_NOIO);
1935 
1936 			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1937 				netif_tx_wake_all_queues(dev->net);
1938 			tasklet_schedule (&dev->bh);
1939 		}
1940 	}
1941 
1942 	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1943 		usb_autopm_get_interface_no_resume(intf);
1944 
1945 	return 0;
1946 }
1947 EXPORT_SYMBOL_GPL(usbnet_resume);
1948 
1949 /*
1950  * Either a subdriver implements manage_power, then it is assumed to always
1951  * be ready to be suspended or it reports the readiness to be suspended
1952  * explicitly
1953  */
1954 void usbnet_device_suggests_idle(struct usbnet *dev)
1955 {
1956 	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1957 		dev->intf->needs_remote_wakeup = 1;
1958 		usb_autopm_put_interface_async(dev->intf);
1959 	}
1960 }
1961 EXPORT_SYMBOL(usbnet_device_suggests_idle);
1962 
1963 /*
1964  * For devices that can do without special commands
1965  */
1966 int usbnet_manage_power(struct usbnet *dev, int on)
1967 {
1968 	dev->intf->needs_remote_wakeup = on;
1969 	return 0;
1970 }
1971 EXPORT_SYMBOL(usbnet_manage_power);
1972 
1973 void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
1974 {
1975 	/* update link after link is reseted */
1976 	if (link && !need_reset)
1977 		netif_carrier_on(dev->net);
1978 	else
1979 		netif_carrier_off(dev->net);
1980 
1981 	if (need_reset && link)
1982 		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
1983 	else
1984 		usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
1985 }
1986 EXPORT_SYMBOL(usbnet_link_change);
1987 
1988 /*-------------------------------------------------------------------------*/
1989 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1990 			     u16 value, u16 index, void *data, u16 size)
1991 {
1992 	void *buf = NULL;
1993 	int err = -ENOMEM;
1994 
1995 	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
1996 		   " value=0x%04x index=0x%04x size=%d\n",
1997 		   cmd, reqtype, value, index, size);
1998 
1999 	if (size) {
2000 		buf = kmalloc(size, GFP_KERNEL);
2001 		if (!buf)
2002 			goto out;
2003 	}
2004 
2005 	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
2006 			      cmd, reqtype, value, index, buf, size,
2007 			      USB_CTRL_GET_TIMEOUT);
2008 	if (err > 0 && err <= size) {
2009 		if (data)
2010 			memcpy(data, buf, err);
2011 		else
2012 			netdev_dbg(dev->net,
2013 				   "Huh? Data requested but thrown away.\n");
2014 	}
2015 	kfree(buf);
2016 out:
2017 	return err;
2018 }
2019 
2020 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2021 			      u16 value, u16 index, const void *data,
2022 			      u16 size)
2023 {
2024 	void *buf = NULL;
2025 	int err = -ENOMEM;
2026 
2027 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2028 		   " value=0x%04x index=0x%04x size=%d\n",
2029 		   cmd, reqtype, value, index, size);
2030 
2031 	if (data) {
2032 		buf = kmemdup(data, size, GFP_KERNEL);
2033 		if (!buf)
2034 			goto out;
2035 	} else {
2036         if (size) {
2037             WARN_ON_ONCE(1);
2038             err = -EINVAL;
2039             goto out;
2040         }
2041     }
2042 
2043 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
2044 			      cmd, reqtype, value, index, buf, size,
2045 			      USB_CTRL_SET_TIMEOUT);
2046 	kfree(buf);
2047 
2048 out:
2049 	return err;
2050 }
2051 
2052 /*
2053  * The function can't be called inside suspend/resume callback,
2054  * otherwise deadlock will be caused.
2055  */
2056 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2057 		    u16 value, u16 index, void *data, u16 size)
2058 {
2059 	int ret;
2060 
2061 	if (usb_autopm_get_interface(dev->intf) < 0)
2062 		return -ENODEV;
2063 	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2064 				data, size);
2065 	usb_autopm_put_interface(dev->intf);
2066 	return ret;
2067 }
2068 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
2069 
2070 /*
2071  * The function can't be called inside suspend/resume callback,
2072  * otherwise deadlock will be caused.
2073  */
2074 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2075 		     u16 value, u16 index, const void *data, u16 size)
2076 {
2077 	int ret;
2078 
2079 	if (usb_autopm_get_interface(dev->intf) < 0)
2080 		return -ENODEV;
2081 	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2082 				 data, size);
2083 	usb_autopm_put_interface(dev->intf);
2084 	return ret;
2085 }
2086 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
2087 
2088 /*
2089  * The function can be called inside suspend/resume callback safely
2090  * and should only be called by suspend/resume callback generally.
2091  */
2092 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2093 			  u16 value, u16 index, void *data, u16 size)
2094 {
2095 	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2096 				 data, size);
2097 }
2098 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
2099 
2100 /*
2101  * The function can be called inside suspend/resume callback safely
2102  * and should only be called by suspend/resume callback generally.
2103  */
2104 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2105 			  u16 value, u16 index, const void *data,
2106 			  u16 size)
2107 {
2108 	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2109 				  data, size);
2110 }
2111 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
2112 
2113 static void usbnet_async_cmd_cb(struct urb *urb)
2114 {
2115 	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
2116 	int status = urb->status;
2117 
2118 	if (status < 0)
2119 		dev_dbg(&urb->dev->dev, "%s failed with %d",
2120 			__func__, status);
2121 
2122 	kfree(req);
2123 	usb_free_urb(urb);
2124 }
2125 
2126 /*
2127  * The caller must make sure that device can't be put into suspend
2128  * state until the control URB completes.
2129  */
2130 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
2131 			   u16 value, u16 index, const void *data, u16 size)
2132 {
2133 	struct usb_ctrlrequest *req = NULL;
2134 	struct urb *urb;
2135 	int err = -ENOMEM;
2136 	void *buf = NULL;
2137 
2138 	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2139 		   " value=0x%04x index=0x%04x size=%d\n",
2140 		   cmd, reqtype, value, index, size);
2141 
2142 	urb = usb_alloc_urb(0, GFP_ATOMIC);
2143 	if (!urb)
2144 		goto fail;
2145 
2146 	if (data) {
2147 		buf = kmemdup(data, size, GFP_ATOMIC);
2148 		if (!buf) {
2149 			netdev_err(dev->net, "Error allocating buffer"
2150 				   " in %s!\n", __func__);
2151 			goto fail_free;
2152 		}
2153 	}
2154 
2155 	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
2156 	if (!req)
2157 		goto fail_free_buf;
2158 
2159 	req->bRequestType = reqtype;
2160 	req->bRequest = cmd;
2161 	req->wValue = cpu_to_le16(value);
2162 	req->wIndex = cpu_to_le16(index);
2163 	req->wLength = cpu_to_le16(size);
2164 
2165 	usb_fill_control_urb(urb, dev->udev,
2166 			     usb_sndctrlpipe(dev->udev, 0),
2167 			     (void *)req, buf, size,
2168 			     usbnet_async_cmd_cb, req);
2169 	urb->transfer_flags |= URB_FREE_BUFFER;
2170 
2171 	err = usb_submit_urb(urb, GFP_ATOMIC);
2172 	if (err < 0) {
2173 		netdev_err(dev->net, "Error submitting the control"
2174 			   " message: status=%d\n", err);
2175 		goto fail_free;
2176 	}
2177 	return 0;
2178 
2179 fail_free_buf:
2180 	kfree(buf);
2181 fail_free:
2182 	kfree(req);
2183 	usb_free_urb(urb);
2184 fail:
2185 	return err;
2186 
2187 }
2188 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
2189 /*-------------------------------------------------------------------------*/
2190 
2191 static int __init usbnet_init(void)
2192 {
2193 	/* Compiler should optimize this out. */
2194 	BUILD_BUG_ON(
2195 		sizeof_field(struct sk_buff, cb) < sizeof(struct skb_data));
2196 
2197 	eth_random_addr(node_id);
2198 	return 0;
2199 }
2200 module_init(usbnet_init);
2201 
2202 static void __exit usbnet_exit(void)
2203 {
2204 }
2205 module_exit(usbnet_exit);
2206 
2207 MODULE_AUTHOR("David Brownell");
2208 MODULE_DESCRIPTION("USB network driver framework");
2209 MODULE_LICENSE("GPL");
2210