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  */
54 void 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 
61 void xenvif_skb_zerocopy_complete(struct xenvif_queue *queue)
62 {
63 	atomic_dec(&queue->inflight_packets);
64 }
65 
66 int 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 
73 static 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 
83 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 
108 static 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 
117 irqreturn_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 
125 int 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 
132 void 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 
139 static 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 
182 static 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 
205 out:
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 
214 static 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 
230 static 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 
246 static 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 
255 static 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 
264 static 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 
275 static 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 
294 static 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 
326 static 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 
336 static 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 	struct xenvif_stats *vif_stats;
344 
345 	for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++) {
346 		unsigned long accum = 0;
347 		for (queue_index = 0; queue_index < num_queues; ++queue_index) {
348 			vif_stats = &vif->queues[queue_index].stats;
349 			accum += *(unsigned long *)(vif_stats + xenvif_stats[i].offset);
350 		}
351 		data[i] = accum;
352 	}
353 }
354 
355 static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
356 {
357 	int i;
358 
359 	switch (stringset) {
360 	case ETH_SS_STATS:
361 		for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
362 			memcpy(data + i * ETH_GSTRING_LEN,
363 			       xenvif_stats[i].name, ETH_GSTRING_LEN);
364 		break;
365 	}
366 }
367 
368 static const struct ethtool_ops xenvif_ethtool_ops = {
369 	.get_link	= ethtool_op_get_link,
370 
371 	.get_sset_count = xenvif_get_sset_count,
372 	.get_ethtool_stats = xenvif_get_ethtool_stats,
373 	.get_strings = xenvif_get_strings,
374 };
375 
376 static const struct net_device_ops xenvif_netdev_ops = {
377 	.ndo_start_xmit	= xenvif_start_xmit,
378 	.ndo_get_stats	= xenvif_get_stats,
379 	.ndo_open	= xenvif_open,
380 	.ndo_stop	= xenvif_close,
381 	.ndo_change_mtu	= xenvif_change_mtu,
382 	.ndo_fix_features = xenvif_fix_features,
383 	.ndo_set_mac_address = eth_mac_addr,
384 	.ndo_validate_addr   = eth_validate_addr,
385 };
386 
387 struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
388 			    unsigned int handle)
389 {
390 	int err;
391 	struct net_device *dev;
392 	struct xenvif *vif;
393 	char name[IFNAMSIZ] = {};
394 
395 	snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
396 	/* Allocate a netdev with the max. supported number of queues.
397 	 * When the guest selects the desired number, it will be updated
398 	 * via netif_set_real_num_*_queues().
399 	 */
400 	dev = alloc_netdev_mq(sizeof(struct xenvif), name, NET_NAME_UNKNOWN,
401 			      ether_setup, xenvif_max_queues);
402 	if (dev == NULL) {
403 		pr_warn("Could not allocate netdev for %s\n", name);
404 		return ERR_PTR(-ENOMEM);
405 	}
406 
407 	SET_NETDEV_DEV(dev, parent);
408 
409 	vif = netdev_priv(dev);
410 
411 	vif->domid  = domid;
412 	vif->handle = handle;
413 	vif->can_sg = 1;
414 	vif->ip_csum = 1;
415 	vif->dev = dev;
416 	vif->disabled = false;
417 	vif->drain_timeout = msecs_to_jiffies(rx_drain_timeout_msecs);
418 	vif->stall_timeout = msecs_to_jiffies(rx_stall_timeout_msecs);
419 
420 	/* Start out with no queues. */
421 	vif->queues = NULL;
422 	vif->num_queues = 0;
423 
424 	spin_lock_init(&vif->lock);
425 
426 	dev->netdev_ops	= &xenvif_netdev_ops;
427 	dev->hw_features = NETIF_F_SG |
428 		NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
429 		NETIF_F_TSO | NETIF_F_TSO6;
430 	dev->features = dev->hw_features | NETIF_F_RXCSUM;
431 	dev->ethtool_ops = &xenvif_ethtool_ops;
432 
433 	dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
434 
435 	/*
436 	 * Initialise a dummy MAC address. We choose the numerically
437 	 * largest non-broadcast address to prevent the address getting
438 	 * stolen by an Ethernet bridge for STP purposes.
439 	 * (FE:FF:FF:FF:FF:FF)
440 	 */
441 	memset(dev->dev_addr, 0xFF, ETH_ALEN);
442 	dev->dev_addr[0] &= ~0x01;
443 
444 	netif_carrier_off(dev);
445 
446 	err = register_netdev(dev);
447 	if (err) {
448 		netdev_warn(dev, "Could not register device: err=%d\n", err);
449 		free_netdev(dev);
450 		return ERR_PTR(err);
451 	}
452 
453 	netdev_dbg(dev, "Successfully created xenvif\n");
454 
455 	__module_get(THIS_MODULE);
456 
457 	return vif;
458 }
459 
460 int xenvif_init_queue(struct xenvif_queue *queue)
461 {
462 	int err, i;
463 
464 	queue->credit_bytes = queue->remaining_credit = ~0UL;
465 	queue->credit_usec  = 0UL;
466 	init_timer(&queue->credit_timeout);
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 = alloc_xenballooned_pages(MAX_PENDING_REQS,
487 				       queue->mmap_pages,
488 				       false);
489 	if (err) {
490 		netdev_err(queue->vif->dev, "Could not reserve mmap_pages\n");
491 		return -ENOMEM;
492 	}
493 
494 	for (i = 0; i < MAX_PENDING_REQS; i++) {
495 		queue->pending_tx_info[i].callback_struct = (struct ubuf_info)
496 			{ .callback = xenvif_zerocopy_callback,
497 			  .ctx = NULL,
498 			  .desc = i };
499 		queue->grant_tx_handle[i] = NETBACK_INVALID_HANDLE;
500 	}
501 
502 	return 0;
503 }
504 
505 void xenvif_carrier_on(struct xenvif *vif)
506 {
507 	rtnl_lock();
508 	if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
509 		dev_set_mtu(vif->dev, ETH_DATA_LEN);
510 	netdev_update_features(vif->dev);
511 	set_bit(VIF_STATUS_CONNECTED, &vif->status);
512 	if (netif_running(vif->dev))
513 		xenvif_up(vif);
514 	rtnl_unlock();
515 }
516 
517 int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
518 		   unsigned long rx_ring_ref, unsigned int tx_evtchn,
519 		   unsigned int rx_evtchn)
520 {
521 	struct task_struct *task;
522 	int err = -ENOMEM;
523 
524 	BUG_ON(queue->tx_irq);
525 	BUG_ON(queue->task);
526 	BUG_ON(queue->dealloc_task);
527 
528 	err = xenvif_map_frontend_rings(queue, tx_ring_ref, rx_ring_ref);
529 	if (err < 0)
530 		goto err;
531 
532 	init_waitqueue_head(&queue->wq);
533 	init_waitqueue_head(&queue->dealloc_wq);
534 	atomic_set(&queue->inflight_packets, 0);
535 
536 	netif_napi_add(queue->vif->dev, &queue->napi, xenvif_poll,
537 			XENVIF_NAPI_WEIGHT);
538 
539 	if (tx_evtchn == rx_evtchn) {
540 		/* feature-split-event-channels == 0 */
541 		err = bind_interdomain_evtchn_to_irqhandler(
542 			queue->vif->domid, tx_evtchn, xenvif_interrupt, 0,
543 			queue->name, queue);
544 		if (err < 0)
545 			goto err_unmap;
546 		queue->tx_irq = queue->rx_irq = err;
547 		disable_irq(queue->tx_irq);
548 	} else {
549 		/* feature-split-event-channels == 1 */
550 		snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
551 			 "%s-tx", queue->name);
552 		err = bind_interdomain_evtchn_to_irqhandler(
553 			queue->vif->domid, tx_evtchn, xenvif_tx_interrupt, 0,
554 			queue->tx_irq_name, queue);
555 		if (err < 0)
556 			goto err_unmap;
557 		queue->tx_irq = err;
558 		disable_irq(queue->tx_irq);
559 
560 		snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
561 			 "%s-rx", queue->name);
562 		err = bind_interdomain_evtchn_to_irqhandler(
563 			queue->vif->domid, rx_evtchn, xenvif_rx_interrupt, 0,
564 			queue->rx_irq_name, queue);
565 		if (err < 0)
566 			goto err_tx_unbind;
567 		queue->rx_irq = err;
568 		disable_irq(queue->rx_irq);
569 	}
570 
571 	queue->stalled = true;
572 
573 	task = kthread_create(xenvif_kthread_guest_rx,
574 			      (void *)queue, "%s-guest-rx", queue->name);
575 	if (IS_ERR(task)) {
576 		pr_warn("Could not allocate kthread for %s\n", queue->name);
577 		err = PTR_ERR(task);
578 		goto err_rx_unbind;
579 	}
580 	queue->task = 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 
596 err_rx_unbind:
597 	unbind_from_irqhandler(queue->rx_irq, queue);
598 	queue->rx_irq = 0;
599 err_tx_unbind:
600 	unbind_from_irqhandler(queue->tx_irq, queue);
601 	queue->tx_irq = 0;
602 err_unmap:
603 	xenvif_unmap_frontend_rings(queue);
604 err:
605 	module_put(THIS_MODULE);
606 	return err;
607 }
608 
609 void 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 
622 void 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 			queue->task = NULL;
638 		}
639 
640 		if (queue->dealloc_task) {
641 			kthread_stop(queue->dealloc_task);
642 			queue->dealloc_task = NULL;
643 		}
644 
645 		if (queue->tx_irq) {
646 			if (queue->tx_irq == queue->rx_irq)
647 				unbind_from_irqhandler(queue->tx_irq, queue);
648 			else {
649 				unbind_from_irqhandler(queue->tx_irq, queue);
650 				unbind_from_irqhandler(queue->rx_irq, queue);
651 			}
652 			queue->tx_irq = 0;
653 		}
654 
655 		xenvif_unmap_frontend_rings(queue);
656 	}
657 }
658 
659 /* Reverse the relevant parts of xenvif_init_queue().
660  * Used for queue teardown from xenvif_free(), and on the
661  * error handling paths in xenbus.c:connect().
662  */
663 void xenvif_deinit_queue(struct xenvif_queue *queue)
664 {
665 	free_xenballooned_pages(MAX_PENDING_REQS, queue->mmap_pages);
666 }
667 
668 void xenvif_free(struct xenvif *vif)
669 {
670 	struct xenvif_queue *queue = NULL;
671 	unsigned int num_queues = vif->num_queues;
672 	unsigned int queue_index;
673 
674 	unregister_netdev(vif->dev);
675 
676 	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
677 		queue = &vif->queues[queue_index];
678 		xenvif_deinit_queue(queue);
679 	}
680 
681 	vfree(vif->queues);
682 	vif->queues = NULL;
683 	vif->num_queues = 0;
684 
685 	free_netdev(vif->dev);
686 
687 	module_put(THIS_MODULE);
688 }
689