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 /* This function is used to set SKBTX_DEV_ZEROCOPY as well as
47  * increasing the inflight counter. We need to increase the inflight
48  * counter because core driver calls into xenvif_zerocopy_callback
49  * which calls xenvif_skb_zerocopy_complete.
50  */
51 void xenvif_skb_zerocopy_prepare(struct xenvif_queue *queue,
52 				 struct sk_buff *skb)
53 {
54 	skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
55 	atomic_inc(&queue->inflight_packets);
56 }
57 
58 void xenvif_skb_zerocopy_complete(struct xenvif_queue *queue)
59 {
60 	atomic_dec(&queue->inflight_packets);
61 }
62 
63 static inline void xenvif_stop_queue(struct xenvif_queue *queue)
64 {
65 	struct net_device *dev = queue->vif->dev;
66 
67 	if (!queue->vif->can_queue)
68 		return;
69 
70 	netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
71 }
72 
73 int xenvif_schedulable(struct xenvif *vif)
74 {
75 	return netif_running(vif->dev) &&
76 		test_bit(VIF_STATUS_CONNECTED, &vif->status);
77 }
78 
79 static irqreturn_t xenvif_tx_interrupt(int irq, void *dev_id)
80 {
81 	struct xenvif_queue *queue = dev_id;
82 
83 	if (RING_HAS_UNCONSUMED_REQUESTS(&queue->tx))
84 		napi_schedule(&queue->napi);
85 
86 	return IRQ_HANDLED;
87 }
88 
89 int xenvif_poll(struct napi_struct *napi, int budget)
90 {
91 	struct xenvif_queue *queue =
92 		container_of(napi, struct xenvif_queue, napi);
93 	int work_done;
94 
95 	/* This vif is rogue, we pretend we've there is nothing to do
96 	 * for this vif to deschedule it from NAPI. But this interface
97 	 * will be turned off in thread context later.
98 	 */
99 	if (unlikely(queue->vif->disabled)) {
100 		napi_complete(napi);
101 		return 0;
102 	}
103 
104 	work_done = xenvif_tx_action(queue, budget);
105 
106 	if (work_done < budget) {
107 		napi_complete(napi);
108 		xenvif_napi_schedule_or_enable_events(queue);
109 	}
110 
111 	return work_done;
112 }
113 
114 static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id)
115 {
116 	struct xenvif_queue *queue = dev_id;
117 	struct netdev_queue *net_queue =
118 		netdev_get_tx_queue(queue->vif->dev, queue->id);
119 
120 	/* QUEUE_STATUS_RX_PURGE_EVENT is only set if either QDisc was off OR
121 	 * the carrier went down and this queue was previously blocked
122 	 */
123 	if (unlikely(netif_tx_queue_stopped(net_queue) ||
124 		     (!netif_carrier_ok(queue->vif->dev) &&
125 		      test_bit(QUEUE_STATUS_RX_STALLED, &queue->status))))
126 		set_bit(QUEUE_STATUS_RX_PURGE_EVENT, &queue->status);
127 	xenvif_kick_thread(queue);
128 
129 	return IRQ_HANDLED;
130 }
131 
132 irqreturn_t xenvif_interrupt(int irq, void *dev_id)
133 {
134 	xenvif_tx_interrupt(irq, dev_id);
135 	xenvif_rx_interrupt(irq, dev_id);
136 
137 	return IRQ_HANDLED;
138 }
139 
140 int xenvif_queue_stopped(struct xenvif_queue *queue)
141 {
142 	struct net_device *dev = queue->vif->dev;
143 	unsigned int id = queue->id;
144 	return netif_tx_queue_stopped(netdev_get_tx_queue(dev, id));
145 }
146 
147 void xenvif_wake_queue(struct xenvif_queue *queue)
148 {
149 	struct net_device *dev = queue->vif->dev;
150 	unsigned int id = queue->id;
151 	netif_tx_wake_queue(netdev_get_tx_queue(dev, id));
152 }
153 
154 /* Callback to wake the queue's thread and turn the carrier off on timeout */
155 static void xenvif_rx_stalled(unsigned long data)
156 {
157 	struct xenvif_queue *queue = (struct xenvif_queue *)data;
158 
159 	if (xenvif_queue_stopped(queue)) {
160 		set_bit(QUEUE_STATUS_RX_PURGE_EVENT, &queue->status);
161 		xenvif_kick_thread(queue);
162 	}
163 }
164 
165 static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
166 {
167 	struct xenvif *vif = netdev_priv(dev);
168 	struct xenvif_queue *queue = NULL;
169 	unsigned int num_queues = vif->num_queues;
170 	u16 index;
171 	int min_slots_needed;
172 
173 	BUG_ON(skb->dev != dev);
174 
175 	/* Drop the packet if queues are not set up */
176 	if (num_queues < 1)
177 		goto drop;
178 
179 	/* Obtain the queue to be used to transmit this packet */
180 	index = skb_get_queue_mapping(skb);
181 	if (index >= num_queues) {
182 		pr_warn_ratelimited("Invalid queue %hu for packet on interface %s\n.",
183 				    index, vif->dev->name);
184 		index %= num_queues;
185 	}
186 	queue = &vif->queues[index];
187 
188 	/* Drop the packet if queue is not ready */
189 	if (queue->task == NULL ||
190 	    queue->dealloc_task == NULL ||
191 	    !xenvif_schedulable(vif))
192 		goto drop;
193 
194 	/* At best we'll need one slot for the header and one for each
195 	 * frag.
196 	 */
197 	min_slots_needed = 1 + skb_shinfo(skb)->nr_frags;
198 
199 	/* If the skb is GSO then we'll also need an extra slot for the
200 	 * metadata.
201 	 */
202 	if (skb_is_gso(skb))
203 		min_slots_needed++;
204 
205 	/* If the skb can't possibly fit in the remaining slots
206 	 * then turn off the queue to give the ring a chance to
207 	 * drain.
208 	 */
209 	if (!xenvif_rx_ring_slots_available(queue, min_slots_needed)) {
210 		queue->rx_stalled.function = xenvif_rx_stalled;
211 		queue->rx_stalled.data = (unsigned long)queue;
212 		xenvif_stop_queue(queue);
213 		mod_timer(&queue->rx_stalled,
214 			  jiffies + rx_drain_timeout_jiffies);
215 	}
216 
217 	skb_queue_tail(&queue->rx_queue, skb);
218 	xenvif_kick_thread(queue);
219 
220 	return NETDEV_TX_OK;
221 
222  drop:
223 	vif->dev->stats.tx_dropped++;
224 	dev_kfree_skb(skb);
225 	return NETDEV_TX_OK;
226 }
227 
228 static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
229 {
230 	struct xenvif *vif = netdev_priv(dev);
231 	struct xenvif_queue *queue = NULL;
232 	unsigned int num_queues = vif->num_queues;
233 	unsigned long rx_bytes = 0;
234 	unsigned long rx_packets = 0;
235 	unsigned long tx_bytes = 0;
236 	unsigned long tx_packets = 0;
237 	unsigned int index;
238 
239 	if (vif->queues == NULL)
240 		goto out;
241 
242 	/* Aggregate tx and rx stats from each queue */
243 	for (index = 0; index < num_queues; ++index) {
244 		queue = &vif->queues[index];
245 		rx_bytes += queue->stats.rx_bytes;
246 		rx_packets += queue->stats.rx_packets;
247 		tx_bytes += queue->stats.tx_bytes;
248 		tx_packets += queue->stats.tx_packets;
249 	}
250 
251 out:
252 	vif->dev->stats.rx_bytes = rx_bytes;
253 	vif->dev->stats.rx_packets = rx_packets;
254 	vif->dev->stats.tx_bytes = tx_bytes;
255 	vif->dev->stats.tx_packets = tx_packets;
256 
257 	return &vif->dev->stats;
258 }
259 
260 static void xenvif_up(struct xenvif *vif)
261 {
262 	struct xenvif_queue *queue = NULL;
263 	unsigned int num_queues = vif->num_queues;
264 	unsigned int queue_index;
265 
266 	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
267 		queue = &vif->queues[queue_index];
268 		napi_enable(&queue->napi);
269 		enable_irq(queue->tx_irq);
270 		if (queue->tx_irq != queue->rx_irq)
271 			enable_irq(queue->rx_irq);
272 		xenvif_napi_schedule_or_enable_events(queue);
273 	}
274 }
275 
276 static void xenvif_down(struct xenvif *vif)
277 {
278 	struct xenvif_queue *queue = NULL;
279 	unsigned int num_queues = vif->num_queues;
280 	unsigned int queue_index;
281 
282 	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
283 		queue = &vif->queues[queue_index];
284 		napi_disable(&queue->napi);
285 		disable_irq(queue->tx_irq);
286 		if (queue->tx_irq != queue->rx_irq)
287 			disable_irq(queue->rx_irq);
288 		del_timer_sync(&queue->credit_timeout);
289 	}
290 }
291 
292 static int xenvif_open(struct net_device *dev)
293 {
294 	struct xenvif *vif = netdev_priv(dev);
295 	if (test_bit(VIF_STATUS_CONNECTED, &vif->status))
296 		xenvif_up(vif);
297 	netif_tx_start_all_queues(dev);
298 	return 0;
299 }
300 
301 static int xenvif_close(struct net_device *dev)
302 {
303 	struct xenvif *vif = netdev_priv(dev);
304 	if (test_bit(VIF_STATUS_CONNECTED, &vif->status))
305 		xenvif_down(vif);
306 	netif_tx_stop_all_queues(dev);
307 	return 0;
308 }
309 
310 static int xenvif_change_mtu(struct net_device *dev, int mtu)
311 {
312 	struct xenvif *vif = netdev_priv(dev);
313 	int max = vif->can_sg ? 65535 - VLAN_ETH_HLEN : ETH_DATA_LEN;
314 
315 	if (mtu > max)
316 		return -EINVAL;
317 	dev->mtu = mtu;
318 	return 0;
319 }
320 
321 static netdev_features_t xenvif_fix_features(struct net_device *dev,
322 	netdev_features_t features)
323 {
324 	struct xenvif *vif = netdev_priv(dev);
325 
326 	if (!vif->can_sg)
327 		features &= ~NETIF_F_SG;
328 	if (~(vif->gso_mask | vif->gso_prefix_mask) & GSO_BIT(TCPV4))
329 		features &= ~NETIF_F_TSO;
330 	if (~(vif->gso_mask | vif->gso_prefix_mask) & GSO_BIT(TCPV6))
331 		features &= ~NETIF_F_TSO6;
332 	if (!vif->ip_csum)
333 		features &= ~NETIF_F_IP_CSUM;
334 	if (!vif->ipv6_csum)
335 		features &= ~NETIF_F_IPV6_CSUM;
336 
337 	return features;
338 }
339 
340 static const struct xenvif_stat {
341 	char name[ETH_GSTRING_LEN];
342 	u16 offset;
343 } xenvif_stats[] = {
344 	{
345 		"rx_gso_checksum_fixup",
346 		offsetof(struct xenvif_stats, rx_gso_checksum_fixup)
347 	},
348 	/* If (sent != success + fail), there are probably packets never
349 	 * freed up properly!
350 	 */
351 	{
352 		"tx_zerocopy_sent",
353 		offsetof(struct xenvif_stats, tx_zerocopy_sent),
354 	},
355 	{
356 		"tx_zerocopy_success",
357 		offsetof(struct xenvif_stats, tx_zerocopy_success),
358 	},
359 	{
360 		"tx_zerocopy_fail",
361 		offsetof(struct xenvif_stats, tx_zerocopy_fail)
362 	},
363 	/* Number of packets exceeding MAX_SKB_FRAG slots. You should use
364 	 * a guest with the same MAX_SKB_FRAG
365 	 */
366 	{
367 		"tx_frag_overflow",
368 		offsetof(struct xenvif_stats, tx_frag_overflow)
369 	},
370 };
371 
372 static int xenvif_get_sset_count(struct net_device *dev, int string_set)
373 {
374 	switch (string_set) {
375 	case ETH_SS_STATS:
376 		return ARRAY_SIZE(xenvif_stats);
377 	default:
378 		return -EINVAL;
379 	}
380 }
381 
382 static void xenvif_get_ethtool_stats(struct net_device *dev,
383 				     struct ethtool_stats *stats, u64 * data)
384 {
385 	struct xenvif *vif = netdev_priv(dev);
386 	unsigned int num_queues = vif->num_queues;
387 	int i;
388 	unsigned int queue_index;
389 	struct xenvif_stats *vif_stats;
390 
391 	for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++) {
392 		unsigned long accum = 0;
393 		for (queue_index = 0; queue_index < num_queues; ++queue_index) {
394 			vif_stats = &vif->queues[queue_index].stats;
395 			accum += *(unsigned long *)(vif_stats + xenvif_stats[i].offset);
396 		}
397 		data[i] = accum;
398 	}
399 }
400 
401 static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
402 {
403 	int i;
404 
405 	switch (stringset) {
406 	case ETH_SS_STATS:
407 		for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
408 			memcpy(data + i * ETH_GSTRING_LEN,
409 			       xenvif_stats[i].name, ETH_GSTRING_LEN);
410 		break;
411 	}
412 }
413 
414 static const struct ethtool_ops xenvif_ethtool_ops = {
415 	.get_link	= ethtool_op_get_link,
416 
417 	.get_sset_count = xenvif_get_sset_count,
418 	.get_ethtool_stats = xenvif_get_ethtool_stats,
419 	.get_strings = xenvif_get_strings,
420 };
421 
422 static const struct net_device_ops xenvif_netdev_ops = {
423 	.ndo_start_xmit	= xenvif_start_xmit,
424 	.ndo_get_stats	= xenvif_get_stats,
425 	.ndo_open	= xenvif_open,
426 	.ndo_stop	= xenvif_close,
427 	.ndo_change_mtu	= xenvif_change_mtu,
428 	.ndo_fix_features = xenvif_fix_features,
429 	.ndo_set_mac_address = eth_mac_addr,
430 	.ndo_validate_addr   = eth_validate_addr,
431 };
432 
433 struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
434 			    unsigned int handle)
435 {
436 	int err;
437 	struct net_device *dev;
438 	struct xenvif *vif;
439 	char name[IFNAMSIZ] = {};
440 
441 	snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
442 	/* Allocate a netdev with the max. supported number of queues.
443 	 * When the guest selects the desired number, it will be updated
444 	 * via netif_set_real_num_*_queues().
445 	 */
446 	dev = alloc_netdev_mq(sizeof(struct xenvif), name, NET_NAME_UNKNOWN,
447 			      ether_setup, xenvif_max_queues);
448 	if (dev == NULL) {
449 		pr_warn("Could not allocate netdev for %s\n", name);
450 		return ERR_PTR(-ENOMEM);
451 	}
452 
453 	SET_NETDEV_DEV(dev, parent);
454 
455 	vif = netdev_priv(dev);
456 
457 	vif->domid  = domid;
458 	vif->handle = handle;
459 	vif->can_sg = 1;
460 	vif->ip_csum = 1;
461 	vif->dev = dev;
462 	vif->disabled = false;
463 
464 	/* Start out with no queues. */
465 	vif->queues = NULL;
466 	vif->num_queues = 0;
467 
468 	dev->netdev_ops	= &xenvif_netdev_ops;
469 	dev->hw_features = NETIF_F_SG |
470 		NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
471 		NETIF_F_TSO | NETIF_F_TSO6;
472 	dev->features = dev->hw_features | NETIF_F_RXCSUM;
473 	dev->ethtool_ops = &xenvif_ethtool_ops;
474 
475 	dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
476 
477 	/*
478 	 * Initialise a dummy MAC address. We choose the numerically
479 	 * largest non-broadcast address to prevent the address getting
480 	 * stolen by an Ethernet bridge for STP purposes.
481 	 * (FE:FF:FF:FF:FF:FF)
482 	 */
483 	memset(dev->dev_addr, 0xFF, ETH_ALEN);
484 	dev->dev_addr[0] &= ~0x01;
485 
486 	netif_carrier_off(dev);
487 
488 	err = register_netdev(dev);
489 	if (err) {
490 		netdev_warn(dev, "Could not register device: err=%d\n", err);
491 		free_netdev(dev);
492 		return ERR_PTR(err);
493 	}
494 
495 	netdev_dbg(dev, "Successfully created xenvif\n");
496 
497 	__module_get(THIS_MODULE);
498 
499 	return vif;
500 }
501 
502 int xenvif_init_queue(struct xenvif_queue *queue)
503 {
504 	int err, i;
505 
506 	queue->credit_bytes = queue->remaining_credit = ~0UL;
507 	queue->credit_usec  = 0UL;
508 	init_timer(&queue->credit_timeout);
509 	queue->credit_window_start = get_jiffies_64();
510 
511 	skb_queue_head_init(&queue->rx_queue);
512 	skb_queue_head_init(&queue->tx_queue);
513 
514 	queue->pending_cons = 0;
515 	queue->pending_prod = MAX_PENDING_REQS;
516 	for (i = 0; i < MAX_PENDING_REQS; ++i)
517 		queue->pending_ring[i] = i;
518 
519 	spin_lock_init(&queue->callback_lock);
520 	spin_lock_init(&queue->response_lock);
521 
522 	/* If ballooning is disabled, this will consume real memory, so you
523 	 * better enable it. The long term solution would be to use just a
524 	 * bunch of valid page descriptors, without dependency on ballooning
525 	 */
526 	err = alloc_xenballooned_pages(MAX_PENDING_REQS,
527 				       queue->mmap_pages,
528 				       false);
529 	if (err) {
530 		netdev_err(queue->vif->dev, "Could not reserve mmap_pages\n");
531 		return -ENOMEM;
532 	}
533 
534 	for (i = 0; i < MAX_PENDING_REQS; i++) {
535 		queue->pending_tx_info[i].callback_struct = (struct ubuf_info)
536 			{ .callback = xenvif_zerocopy_callback,
537 			  .ctx = NULL,
538 			  .desc = i };
539 		queue->grant_tx_handle[i] = NETBACK_INVALID_HANDLE;
540 	}
541 
542 	init_timer(&queue->rx_stalled);
543 
544 	return 0;
545 }
546 
547 void xenvif_carrier_on(struct xenvif *vif)
548 {
549 	rtnl_lock();
550 	if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
551 		dev_set_mtu(vif->dev, ETH_DATA_LEN);
552 	netdev_update_features(vif->dev);
553 	set_bit(VIF_STATUS_CONNECTED, &vif->status);
554 	netif_carrier_on(vif->dev);
555 	if (netif_running(vif->dev))
556 		xenvif_up(vif);
557 	rtnl_unlock();
558 }
559 
560 int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
561 		   unsigned long rx_ring_ref, unsigned int tx_evtchn,
562 		   unsigned int rx_evtchn)
563 {
564 	struct task_struct *task;
565 	int err = -ENOMEM;
566 
567 	BUG_ON(queue->tx_irq);
568 	BUG_ON(queue->task);
569 	BUG_ON(queue->dealloc_task);
570 
571 	err = xenvif_map_frontend_rings(queue, tx_ring_ref, rx_ring_ref);
572 	if (err < 0)
573 		goto err;
574 
575 	init_waitqueue_head(&queue->wq);
576 	init_waitqueue_head(&queue->dealloc_wq);
577 	atomic_set(&queue->inflight_packets, 0);
578 
579 	if (tx_evtchn == rx_evtchn) {
580 		/* feature-split-event-channels == 0 */
581 		err = bind_interdomain_evtchn_to_irqhandler(
582 			queue->vif->domid, tx_evtchn, xenvif_interrupt, 0,
583 			queue->name, queue);
584 		if (err < 0)
585 			goto err_unmap;
586 		queue->tx_irq = queue->rx_irq = err;
587 		disable_irq(queue->tx_irq);
588 	} else {
589 		/* feature-split-event-channels == 1 */
590 		snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
591 			 "%s-tx", queue->name);
592 		err = bind_interdomain_evtchn_to_irqhandler(
593 			queue->vif->domid, tx_evtchn, xenvif_tx_interrupt, 0,
594 			queue->tx_irq_name, queue);
595 		if (err < 0)
596 			goto err_unmap;
597 		queue->tx_irq = err;
598 		disable_irq(queue->tx_irq);
599 
600 		snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
601 			 "%s-rx", queue->name);
602 		err = bind_interdomain_evtchn_to_irqhandler(
603 			queue->vif->domid, rx_evtchn, xenvif_rx_interrupt, 0,
604 			queue->rx_irq_name, queue);
605 		if (err < 0)
606 			goto err_tx_unbind;
607 		queue->rx_irq = err;
608 		disable_irq(queue->rx_irq);
609 	}
610 
611 	task = kthread_create(xenvif_kthread_guest_rx,
612 			      (void *)queue, "%s-guest-rx", queue->name);
613 	if (IS_ERR(task)) {
614 		pr_warn("Could not allocate kthread for %s\n", queue->name);
615 		err = PTR_ERR(task);
616 		goto err_rx_unbind;
617 	}
618 	queue->task = task;
619 
620 	task = kthread_create(xenvif_dealloc_kthread,
621 			      (void *)queue, "%s-dealloc", queue->name);
622 	if (IS_ERR(task)) {
623 		pr_warn("Could not allocate kthread for %s\n", queue->name);
624 		err = PTR_ERR(task);
625 		goto err_rx_unbind;
626 	}
627 	queue->dealloc_task = task;
628 
629 	wake_up_process(queue->task);
630 	wake_up_process(queue->dealloc_task);
631 
632 	netif_napi_add(queue->vif->dev, &queue->napi, xenvif_poll,
633 			XENVIF_NAPI_WEIGHT);
634 
635 	return 0;
636 
637 err_rx_unbind:
638 	unbind_from_irqhandler(queue->rx_irq, queue);
639 	queue->rx_irq = 0;
640 err_tx_unbind:
641 	unbind_from_irqhandler(queue->tx_irq, queue);
642 	queue->tx_irq = 0;
643 err_unmap:
644 	xenvif_unmap_frontend_rings(queue);
645 err:
646 	module_put(THIS_MODULE);
647 	return err;
648 }
649 
650 void xenvif_carrier_off(struct xenvif *vif)
651 {
652 	struct net_device *dev = vif->dev;
653 
654 	rtnl_lock();
655 	if (test_and_clear_bit(VIF_STATUS_CONNECTED, &vif->status)) {
656 		netif_carrier_off(dev); /* discard queued packets */
657 		if (netif_running(dev))
658 			xenvif_down(vif);
659 	}
660 	rtnl_unlock();
661 }
662 
663 void xenvif_disconnect(struct xenvif *vif)
664 {
665 	struct xenvif_queue *queue = NULL;
666 	unsigned int num_queues = vif->num_queues;
667 	unsigned int queue_index;
668 
669 	xenvif_carrier_off(vif);
670 
671 	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
672 		queue = &vif->queues[queue_index];
673 
674 		netif_napi_del(&queue->napi);
675 
676 		if (queue->task) {
677 			del_timer_sync(&queue->rx_stalled);
678 			kthread_stop(queue->task);
679 			queue->task = NULL;
680 		}
681 
682 		if (queue->dealloc_task) {
683 			kthread_stop(queue->dealloc_task);
684 			queue->dealloc_task = NULL;
685 		}
686 
687 		if (queue->tx_irq) {
688 			if (queue->tx_irq == queue->rx_irq)
689 				unbind_from_irqhandler(queue->tx_irq, queue);
690 			else {
691 				unbind_from_irqhandler(queue->tx_irq, queue);
692 				unbind_from_irqhandler(queue->rx_irq, queue);
693 			}
694 			queue->tx_irq = 0;
695 		}
696 
697 		xenvif_unmap_frontend_rings(queue);
698 	}
699 }
700 
701 /* Reverse the relevant parts of xenvif_init_queue().
702  * Used for queue teardown from xenvif_free(), and on the
703  * error handling paths in xenbus.c:connect().
704  */
705 void xenvif_deinit_queue(struct xenvif_queue *queue)
706 {
707 	free_xenballooned_pages(MAX_PENDING_REQS, queue->mmap_pages);
708 }
709 
710 void xenvif_free(struct xenvif *vif)
711 {
712 	struct xenvif_queue *queue = NULL;
713 	unsigned int num_queues = vif->num_queues;
714 	unsigned int queue_index;
715 
716 	unregister_netdev(vif->dev);
717 
718 	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
719 		queue = &vif->queues[queue_index];
720 		xenvif_deinit_queue(queue);
721 	}
722 
723 	vfree(vif->queues);
724 	vif->queues = NULL;
725 	vif->num_queues = 0;
726 
727 	free_netdev(vif->dev);
728 
729 	module_put(THIS_MODULE);
730 }
731