1/*
2 * Network-device interface management.
3 *
4 * Copyright (c) 2004-2005, Keir Fraser
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License version 2
8 * as published by the Free Software Foundation; or, when distributed
9 * separately from the Linux kernel or incorporated into other
10 * software packages, subject to the following license:
11 *
12 * Permission is hereby granted, free of charge, to any person obtaining a copy
13 * of this source file (the "Software"), to deal in the Software without
14 * restriction, including without limitation the rights to use, copy, modify,
15 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
16 * and to permit persons to whom the Software is furnished to do so, subject to
17 * the following conditions:
18 *
19 * The above copyright notice and this permission notice shall be included in
20 * all copies or substantial portions of the Software.
21 *
22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
25 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
26 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
27 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
28 * IN THE SOFTWARE.
29 */
30
31#include "common.h"
32
33#include <linux/kthread.h>
34#include <linux/ethtool.h>
35#include <linux/rtnetlink.h>
36#include <linux/if_vlan.h>
37#include <linux/vmalloc.h>
38
39#include <xen/events.h>
40#include <asm/xen/hypercall.h>
41#include <xen/balloon.h>
42
43#define XENVIF_QUEUE_LENGTH 32
44#define XENVIF_NAPI_WEIGHT  64
45
46/* Number of bytes allowed on the internal guest Rx queue. */
47#define XENVIF_RX_QUEUE_BYTES (XEN_NETIF_RX_RING_SIZE/2 * PAGE_SIZE)
48
49/* This function is used to set SKBTX_DEV_ZEROCOPY as well as
50 * increasing the inflight counter. We need to increase the inflight
51 * counter because core driver calls into xenvif_zerocopy_callback
52 * which calls xenvif_skb_zerocopy_complete.
53 */
54void xenvif_skb_zerocopy_prepare(struct xenvif_queue *queue,
55				 struct sk_buff *skb)
56{
57	skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
58	atomic_inc(&queue->inflight_packets);
59}
60
61void xenvif_skb_zerocopy_complete(struct xenvif_queue *queue)
62{
63	atomic_dec(&queue->inflight_packets);
64}
65
66int xenvif_schedulable(struct xenvif *vif)
67{
68	return netif_running(vif->dev) &&
69		test_bit(VIF_STATUS_CONNECTED, &vif->status) &&
70		!vif->disabled;
71}
72
73static irqreturn_t xenvif_tx_interrupt(int irq, void *dev_id)
74{
75	struct xenvif_queue *queue = dev_id;
76
77	if (RING_HAS_UNCONSUMED_REQUESTS(&queue->tx))
78		napi_schedule(&queue->napi);
79
80	return IRQ_HANDLED;
81}
82
83static int xenvif_poll(struct napi_struct *napi, int budget)
84{
85	struct xenvif_queue *queue =
86		container_of(napi, struct xenvif_queue, napi);
87	int work_done;
88
89	/* This vif is rogue, we pretend we've there is nothing to do
90	 * for this vif to deschedule it from NAPI. But this interface
91	 * will be turned off in thread context later.
92	 */
93	if (unlikely(queue->vif->disabled)) {
94		napi_complete(napi);
95		return 0;
96	}
97
98	work_done = xenvif_tx_action(queue, budget);
99
100	if (work_done < budget) {
101		napi_complete(napi);
102		xenvif_napi_schedule_or_enable_events(queue);
103	}
104
105	return work_done;
106}
107
108static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id)
109{
110	struct xenvif_queue *queue = dev_id;
111
112	xenvif_kick_thread(queue);
113
114	return IRQ_HANDLED;
115}
116
117irqreturn_t xenvif_interrupt(int irq, void *dev_id)
118{
119	xenvif_tx_interrupt(irq, dev_id);
120	xenvif_rx_interrupt(irq, dev_id);
121
122	return IRQ_HANDLED;
123}
124
125int xenvif_queue_stopped(struct xenvif_queue *queue)
126{
127	struct net_device *dev = queue->vif->dev;
128	unsigned int id = queue->id;
129	return netif_tx_queue_stopped(netdev_get_tx_queue(dev, id));
130}
131
132void xenvif_wake_queue(struct xenvif_queue *queue)
133{
134	struct net_device *dev = queue->vif->dev;
135	unsigned int id = queue->id;
136	netif_tx_wake_queue(netdev_get_tx_queue(dev, id));
137}
138
139static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
140{
141	struct xenvif *vif = netdev_priv(dev);
142	struct xenvif_queue *queue = NULL;
143	unsigned int num_queues = vif->num_queues;
144	u16 index;
145	struct xenvif_rx_cb *cb;
146
147	BUG_ON(skb->dev != dev);
148
149	/* Drop the packet if queues are not set up */
150	if (num_queues < 1)
151		goto drop;
152
153	/* Obtain the queue to be used to transmit this packet */
154	index = skb_get_queue_mapping(skb);
155	if (index >= num_queues) {
156		pr_warn_ratelimited("Invalid queue %hu for packet on interface %s\n.",
157				    index, vif->dev->name);
158		index %= num_queues;
159	}
160	queue = &vif->queues[index];
161
162	/* Drop the packet if queue is not ready */
163	if (queue->task == NULL ||
164	    queue->dealloc_task == NULL ||
165	    !xenvif_schedulable(vif))
166		goto drop;
167
168	cb = XENVIF_RX_CB(skb);
169	cb->expires = jiffies + vif->drain_timeout;
170
171	xenvif_rx_queue_tail(queue, skb);
172	xenvif_kick_thread(queue);
173
174	return NETDEV_TX_OK;
175
176 drop:
177	vif->dev->stats.tx_dropped++;
178	dev_kfree_skb(skb);
179	return NETDEV_TX_OK;
180}
181
182static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
183{
184	struct xenvif *vif = netdev_priv(dev);
185	struct xenvif_queue *queue = NULL;
186	unsigned int num_queues = vif->num_queues;
187	unsigned long rx_bytes = 0;
188	unsigned long rx_packets = 0;
189	unsigned long tx_bytes = 0;
190	unsigned long tx_packets = 0;
191	unsigned int index;
192
193	if (vif->queues == NULL)
194		goto out;
195
196	/* Aggregate tx and rx stats from each queue */
197	for (index = 0; index < num_queues; ++index) {
198		queue = &vif->queues[index];
199		rx_bytes += queue->stats.rx_bytes;
200		rx_packets += queue->stats.rx_packets;
201		tx_bytes += queue->stats.tx_bytes;
202		tx_packets += queue->stats.tx_packets;
203	}
204
205out:
206	vif->dev->stats.rx_bytes = rx_bytes;
207	vif->dev->stats.rx_packets = rx_packets;
208	vif->dev->stats.tx_bytes = tx_bytes;
209	vif->dev->stats.tx_packets = tx_packets;
210
211	return &vif->dev->stats;
212}
213
214static void xenvif_up(struct xenvif *vif)
215{
216	struct xenvif_queue *queue = NULL;
217	unsigned int num_queues = vif->num_queues;
218	unsigned int queue_index;
219
220	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
221		queue = &vif->queues[queue_index];
222		napi_enable(&queue->napi);
223		enable_irq(queue->tx_irq);
224		if (queue->tx_irq != queue->rx_irq)
225			enable_irq(queue->rx_irq);
226		xenvif_napi_schedule_or_enable_events(queue);
227	}
228}
229
230static void xenvif_down(struct xenvif *vif)
231{
232	struct xenvif_queue *queue = NULL;
233	unsigned int num_queues = vif->num_queues;
234	unsigned int queue_index;
235
236	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
237		queue = &vif->queues[queue_index];
238		disable_irq(queue->tx_irq);
239		if (queue->tx_irq != queue->rx_irq)
240			disable_irq(queue->rx_irq);
241		napi_disable(&queue->napi);
242		del_timer_sync(&queue->credit_timeout);
243	}
244}
245
246static int xenvif_open(struct net_device *dev)
247{
248	struct xenvif *vif = netdev_priv(dev);
249	if (test_bit(VIF_STATUS_CONNECTED, &vif->status))
250		xenvif_up(vif);
251	netif_tx_start_all_queues(dev);
252	return 0;
253}
254
255static int xenvif_close(struct net_device *dev)
256{
257	struct xenvif *vif = netdev_priv(dev);
258	if (test_bit(VIF_STATUS_CONNECTED, &vif->status))
259		xenvif_down(vif);
260	netif_tx_stop_all_queues(dev);
261	return 0;
262}
263
264static int xenvif_change_mtu(struct net_device *dev, int mtu)
265{
266	struct xenvif *vif = netdev_priv(dev);
267	int max = vif->can_sg ? 65535 - VLAN_ETH_HLEN : ETH_DATA_LEN;
268
269	if (mtu > max)
270		return -EINVAL;
271	dev->mtu = mtu;
272	return 0;
273}
274
275static netdev_features_t xenvif_fix_features(struct net_device *dev,
276	netdev_features_t features)
277{
278	struct xenvif *vif = netdev_priv(dev);
279
280	if (!vif->can_sg)
281		features &= ~NETIF_F_SG;
282	if (~(vif->gso_mask | vif->gso_prefix_mask) & GSO_BIT(TCPV4))
283		features &= ~NETIF_F_TSO;
284	if (~(vif->gso_mask | vif->gso_prefix_mask) & GSO_BIT(TCPV6))
285		features &= ~NETIF_F_TSO6;
286	if (!vif->ip_csum)
287		features &= ~NETIF_F_IP_CSUM;
288	if (!vif->ipv6_csum)
289		features &= ~NETIF_F_IPV6_CSUM;
290
291	return features;
292}
293
294static const struct xenvif_stat {
295	char name[ETH_GSTRING_LEN];
296	u16 offset;
297} xenvif_stats[] = {
298	{
299		"rx_gso_checksum_fixup",
300		offsetof(struct xenvif_stats, rx_gso_checksum_fixup)
301	},
302	/* If (sent != success + fail), there are probably packets never
303	 * freed up properly!
304	 */
305	{
306		"tx_zerocopy_sent",
307		offsetof(struct xenvif_stats, tx_zerocopy_sent),
308	},
309	{
310		"tx_zerocopy_success",
311		offsetof(struct xenvif_stats, tx_zerocopy_success),
312	},
313	{
314		"tx_zerocopy_fail",
315		offsetof(struct xenvif_stats, tx_zerocopy_fail)
316	},
317	/* Number of packets exceeding MAX_SKB_FRAG slots. You should use
318	 * a guest with the same MAX_SKB_FRAG
319	 */
320	{
321		"tx_frag_overflow",
322		offsetof(struct xenvif_stats, tx_frag_overflow)
323	},
324};
325
326static int xenvif_get_sset_count(struct net_device *dev, int string_set)
327{
328	switch (string_set) {
329	case ETH_SS_STATS:
330		return ARRAY_SIZE(xenvif_stats);
331	default:
332		return -EINVAL;
333	}
334}
335
336static void xenvif_get_ethtool_stats(struct net_device *dev,
337				     struct ethtool_stats *stats, u64 * data)
338{
339	struct xenvif *vif = netdev_priv(dev);
340	unsigned int num_queues = vif->num_queues;
341	int i;
342	unsigned int queue_index;
343
344	for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++) {
345		unsigned long accum = 0;
346		for (queue_index = 0; queue_index < num_queues; ++queue_index) {
347			void *vif_stats = &vif->queues[queue_index].stats;
348			accum += *(unsigned long *)(vif_stats + xenvif_stats[i].offset);
349		}
350		data[i] = accum;
351	}
352}
353
354static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
355{
356	int i;
357
358	switch (stringset) {
359	case ETH_SS_STATS:
360		for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
361			memcpy(data + i * ETH_GSTRING_LEN,
362			       xenvif_stats[i].name, ETH_GSTRING_LEN);
363		break;
364	}
365}
366
367static const struct ethtool_ops xenvif_ethtool_ops = {
368	.get_link	= ethtool_op_get_link,
369
370	.get_sset_count = xenvif_get_sset_count,
371	.get_ethtool_stats = xenvif_get_ethtool_stats,
372	.get_strings = xenvif_get_strings,
373};
374
375static const struct net_device_ops xenvif_netdev_ops = {
376	.ndo_start_xmit	= xenvif_start_xmit,
377	.ndo_get_stats	= xenvif_get_stats,
378	.ndo_open	= xenvif_open,
379	.ndo_stop	= xenvif_close,
380	.ndo_change_mtu	= xenvif_change_mtu,
381	.ndo_fix_features = xenvif_fix_features,
382	.ndo_set_mac_address = eth_mac_addr,
383	.ndo_validate_addr   = eth_validate_addr,
384};
385
386struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
387			    unsigned int handle)
388{
389	int err;
390	struct net_device *dev;
391	struct xenvif *vif;
392	char name[IFNAMSIZ] = {};
393
394	snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
395	/* Allocate a netdev with the max. supported number of queues.
396	 * When the guest selects the desired number, it will be updated
397	 * via netif_set_real_num_*_queues().
398	 */
399	dev = alloc_netdev_mq(sizeof(struct xenvif), name, NET_NAME_UNKNOWN,
400			      ether_setup, xenvif_max_queues);
401	if (dev == NULL) {
402		pr_warn("Could not allocate netdev for %s\n", name);
403		return ERR_PTR(-ENOMEM);
404	}
405
406	SET_NETDEV_DEV(dev, parent);
407
408	vif = netdev_priv(dev);
409
410	vif->domid  = domid;
411	vif->handle = handle;
412	vif->can_sg = 1;
413	vif->ip_csum = 1;
414	vif->dev = dev;
415	vif->disabled = false;
416	vif->drain_timeout = msecs_to_jiffies(rx_drain_timeout_msecs);
417	vif->stall_timeout = msecs_to_jiffies(rx_stall_timeout_msecs);
418
419	/* Start out with no queues. */
420	vif->queues = NULL;
421	vif->num_queues = 0;
422
423	spin_lock_init(&vif->lock);
424
425	dev->netdev_ops	= &xenvif_netdev_ops;
426	dev->hw_features = NETIF_F_SG |
427		NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
428		NETIF_F_TSO | NETIF_F_TSO6;
429	dev->features = dev->hw_features | NETIF_F_RXCSUM;
430	dev->ethtool_ops = &xenvif_ethtool_ops;
431
432	dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
433
434	/*
435	 * Initialise a dummy MAC address. We choose the numerically
436	 * largest non-broadcast address to prevent the address getting
437	 * stolen by an Ethernet bridge for STP purposes.
438	 * (FE:FF:FF:FF:FF:FF)
439	 */
440	eth_broadcast_addr(dev->dev_addr);
441	dev->dev_addr[0] &= ~0x01;
442
443	netif_carrier_off(dev);
444
445	err = register_netdev(dev);
446	if (err) {
447		netdev_warn(dev, "Could not register device: err=%d\n", err);
448		free_netdev(dev);
449		return ERR_PTR(err);
450	}
451
452	netdev_dbg(dev, "Successfully created xenvif\n");
453
454	__module_get(THIS_MODULE);
455
456	return vif;
457}
458
459int xenvif_init_queue(struct xenvif_queue *queue)
460{
461	int err, i;
462
463	queue->credit_bytes = queue->remaining_credit = ~0UL;
464	queue->credit_usec  = 0UL;
465	init_timer(&queue->credit_timeout);
466	queue->credit_timeout.function = xenvif_tx_credit_callback;
467	queue->credit_window_start = get_jiffies_64();
468
469	queue->rx_queue_max = XENVIF_RX_QUEUE_BYTES;
470
471	skb_queue_head_init(&queue->rx_queue);
472	skb_queue_head_init(&queue->tx_queue);
473
474	queue->pending_cons = 0;
475	queue->pending_prod = MAX_PENDING_REQS;
476	for (i = 0; i < MAX_PENDING_REQS; ++i)
477		queue->pending_ring[i] = i;
478
479	spin_lock_init(&queue->callback_lock);
480	spin_lock_init(&queue->response_lock);
481
482	/* If ballooning is disabled, this will consume real memory, so you
483	 * better enable it. The long term solution would be to use just a
484	 * bunch of valid page descriptors, without dependency on ballooning
485	 */
486	err = gnttab_alloc_pages(MAX_PENDING_REQS,
487				 queue->mmap_pages);
488	if (err) {
489		netdev_err(queue->vif->dev, "Could not reserve mmap_pages\n");
490		return -ENOMEM;
491	}
492
493	for (i = 0; i < MAX_PENDING_REQS; i++) {
494		queue->pending_tx_info[i].callback_struct = (struct ubuf_info)
495			{ .callback = xenvif_zerocopy_callback,
496			  .ctx = NULL,
497			  .desc = i };
498		queue->grant_tx_handle[i] = NETBACK_INVALID_HANDLE;
499	}
500
501	return 0;
502}
503
504void xenvif_carrier_on(struct xenvif *vif)
505{
506	rtnl_lock();
507	if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
508		dev_set_mtu(vif->dev, ETH_DATA_LEN);
509	netdev_update_features(vif->dev);
510	set_bit(VIF_STATUS_CONNECTED, &vif->status);
511	if (netif_running(vif->dev))
512		xenvif_up(vif);
513	rtnl_unlock();
514}
515
516int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
517		   unsigned long rx_ring_ref, unsigned int tx_evtchn,
518		   unsigned int rx_evtchn)
519{
520	struct task_struct *task;
521	int err = -ENOMEM;
522
523	BUG_ON(queue->tx_irq);
524	BUG_ON(queue->task);
525	BUG_ON(queue->dealloc_task);
526
527	err = xenvif_map_frontend_rings(queue, tx_ring_ref, rx_ring_ref);
528	if (err < 0)
529		goto err;
530
531	init_waitqueue_head(&queue->wq);
532	init_waitqueue_head(&queue->dealloc_wq);
533	atomic_set(&queue->inflight_packets, 0);
534
535	netif_napi_add(queue->vif->dev, &queue->napi, xenvif_poll,
536			XENVIF_NAPI_WEIGHT);
537
538	if (tx_evtchn == rx_evtchn) {
539		/* feature-split-event-channels == 0 */
540		err = bind_interdomain_evtchn_to_irqhandler(
541			queue->vif->domid, tx_evtchn, xenvif_interrupt, 0,
542			queue->name, queue);
543		if (err < 0)
544			goto err_unmap;
545		queue->tx_irq = queue->rx_irq = err;
546		disable_irq(queue->tx_irq);
547	} else {
548		/* feature-split-event-channels == 1 */
549		snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
550			 "%s-tx", queue->name);
551		err = bind_interdomain_evtchn_to_irqhandler(
552			queue->vif->domid, tx_evtchn, xenvif_tx_interrupt, 0,
553			queue->tx_irq_name, queue);
554		if (err < 0)
555			goto err_unmap;
556		queue->tx_irq = err;
557		disable_irq(queue->tx_irq);
558
559		snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
560			 "%s-rx", queue->name);
561		err = bind_interdomain_evtchn_to_irqhandler(
562			queue->vif->domid, rx_evtchn, xenvif_rx_interrupt, 0,
563			queue->rx_irq_name, queue);
564		if (err < 0)
565			goto err_tx_unbind;
566		queue->rx_irq = err;
567		disable_irq(queue->rx_irq);
568	}
569
570	queue->stalled = true;
571
572	task = kthread_create(xenvif_kthread_guest_rx,
573			      (void *)queue, "%s-guest-rx", queue->name);
574	if (IS_ERR(task)) {
575		pr_warn("Could not allocate kthread for %s\n", queue->name);
576		err = PTR_ERR(task);
577		goto err_rx_unbind;
578	}
579	queue->task = task;
580	get_task_struct(task);
581
582	task = kthread_create(xenvif_dealloc_kthread,
583			      (void *)queue, "%s-dealloc", queue->name);
584	if (IS_ERR(task)) {
585		pr_warn("Could not allocate kthread for %s\n", queue->name);
586		err = PTR_ERR(task);
587		goto err_rx_unbind;
588	}
589	queue->dealloc_task = task;
590
591	wake_up_process(queue->task);
592	wake_up_process(queue->dealloc_task);
593
594	return 0;
595
596err_rx_unbind:
597	unbind_from_irqhandler(queue->rx_irq, queue);
598	queue->rx_irq = 0;
599err_tx_unbind:
600	unbind_from_irqhandler(queue->tx_irq, queue);
601	queue->tx_irq = 0;
602err_unmap:
603	xenvif_unmap_frontend_rings(queue);
604err:
605	module_put(THIS_MODULE);
606	return err;
607}
608
609void xenvif_carrier_off(struct xenvif *vif)
610{
611	struct net_device *dev = vif->dev;
612
613	rtnl_lock();
614	if (test_and_clear_bit(VIF_STATUS_CONNECTED, &vif->status)) {
615		netif_carrier_off(dev); /* discard queued packets */
616		if (netif_running(dev))
617			xenvif_down(vif);
618	}
619	rtnl_unlock();
620}
621
622void xenvif_disconnect(struct xenvif *vif)
623{
624	struct xenvif_queue *queue = NULL;
625	unsigned int num_queues = vif->num_queues;
626	unsigned int queue_index;
627
628	xenvif_carrier_off(vif);
629
630	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
631		queue = &vif->queues[queue_index];
632
633		netif_napi_del(&queue->napi);
634
635		if (queue->task) {
636			kthread_stop(queue->task);
637			put_task_struct(queue->task);
638			queue->task = NULL;
639		}
640
641		if (queue->dealloc_task) {
642			kthread_stop(queue->dealloc_task);
643			queue->dealloc_task = NULL;
644		}
645
646		if (queue->tx_irq) {
647			if (queue->tx_irq == queue->rx_irq)
648				unbind_from_irqhandler(queue->tx_irq, queue);
649			else {
650				unbind_from_irqhandler(queue->tx_irq, queue);
651				unbind_from_irqhandler(queue->rx_irq, queue);
652			}
653			queue->tx_irq = 0;
654		}
655
656		xenvif_unmap_frontend_rings(queue);
657	}
658}
659
660/* Reverse the relevant parts of xenvif_init_queue().
661 * Used for queue teardown from xenvif_free(), and on the
662 * error handling paths in xenbus.c:connect().
663 */
664void xenvif_deinit_queue(struct xenvif_queue *queue)
665{
666	gnttab_free_pages(MAX_PENDING_REQS, queue->mmap_pages);
667}
668
669void xenvif_free(struct xenvif *vif)
670{
671	struct xenvif_queue *queue = NULL;
672	unsigned int num_queues = vif->num_queues;
673	unsigned int queue_index;
674
675	unregister_netdev(vif->dev);
676
677	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
678		queue = &vif->queues[queue_index];
679		xenvif_deinit_queue(queue);
680	}
681
682	vfree(vif->queues);
683	vif->queues = NULL;
684	vif->num_queues = 0;
685
686	free_netdev(vif->dev);
687
688	module_put(THIS_MODULE);
689}
690