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 	/* Wake the dealloc thread _after_ decrementing inflight_packets so
66 	 * that if kthread_stop() has already been called, the dealloc thread
67 	 * does not wait forever with nothing to wake it.
68 	 */
69 	wake_up(&queue->dealloc_wq);
70 }
71 
72 int xenvif_schedulable(struct xenvif *vif)
73 {
74 	return netif_running(vif->dev) &&
75 		test_bit(VIF_STATUS_CONNECTED, &vif->status) &&
76 		!vif->disabled;
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 static 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 
118 	xenvif_kick_thread(queue);
119 
120 	return IRQ_HANDLED;
121 }
122 
123 irqreturn_t xenvif_interrupt(int irq, void *dev_id)
124 {
125 	xenvif_tx_interrupt(irq, dev_id);
126 	xenvif_rx_interrupt(irq, dev_id);
127 
128 	return IRQ_HANDLED;
129 }
130 
131 irqreturn_t xenvif_ctrl_interrupt(int irq, void *dev_id)
132 {
133 	struct xenvif *vif = dev_id;
134 
135 	wake_up(&vif->ctrl_wq);
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 static u16 xenvif_select_queue(struct net_device *dev, struct sk_buff *skb,
155 			       void *accel_priv,
156 			       select_queue_fallback_t fallback)
157 {
158 	struct xenvif *vif = netdev_priv(dev);
159 	unsigned int size = vif->hash.size;
160 
161 	if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE) {
162 		u16 index = fallback(dev, skb) % dev->real_num_tx_queues;
163 
164 		/* Make sure there is no hash information in the socket
165 		 * buffer otherwise it would be incorrectly forwarded
166 		 * to the frontend.
167 		 */
168 		skb_clear_hash(skb);
169 
170 		return index;
171 	}
172 
173 	xenvif_set_skb_hash(vif, skb);
174 
175 	if (size == 0)
176 		return skb_get_hash_raw(skb) % dev->real_num_tx_queues;
177 
178 	return vif->hash.mapping[skb_get_hash_raw(skb) % size];
179 }
180 
181 static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
182 {
183 	struct xenvif *vif = netdev_priv(dev);
184 	struct xenvif_queue *queue = NULL;
185 	unsigned int num_queues = vif->num_queues;
186 	u16 index;
187 	struct xenvif_rx_cb *cb;
188 
189 	BUG_ON(skb->dev != dev);
190 
191 	/* Drop the packet if queues are not set up */
192 	if (num_queues < 1)
193 		goto drop;
194 
195 	/* Obtain the queue to be used to transmit this packet */
196 	index = skb_get_queue_mapping(skb);
197 	if (index >= num_queues) {
198 		pr_warn_ratelimited("Invalid queue %hu for packet on interface %s\n.",
199 				    index, vif->dev->name);
200 		index %= num_queues;
201 	}
202 	queue = &vif->queues[index];
203 
204 	/* Drop the packet if queue is not ready */
205 	if (queue->task == NULL ||
206 	    queue->dealloc_task == NULL ||
207 	    !xenvif_schedulable(vif))
208 		goto drop;
209 
210 	if (vif->multicast_control && skb->pkt_type == PACKET_MULTICAST) {
211 		struct ethhdr *eth = (struct ethhdr *)skb->data;
212 
213 		if (!xenvif_mcast_match(vif, eth->h_dest))
214 			goto drop;
215 	}
216 
217 	cb = XENVIF_RX_CB(skb);
218 	cb->expires = jiffies + vif->drain_timeout;
219 
220 	xenvif_rx_queue_tail(queue, skb);
221 	xenvif_kick_thread(queue);
222 
223 	return NETDEV_TX_OK;
224 
225  drop:
226 	vif->dev->stats.tx_dropped++;
227 	dev_kfree_skb(skb);
228 	return NETDEV_TX_OK;
229 }
230 
231 static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
232 {
233 	struct xenvif *vif = netdev_priv(dev);
234 	struct xenvif_queue *queue = NULL;
235 	unsigned int num_queues = vif->num_queues;
236 	unsigned long rx_bytes = 0;
237 	unsigned long rx_packets = 0;
238 	unsigned long tx_bytes = 0;
239 	unsigned long tx_packets = 0;
240 	unsigned int index;
241 
242 	if (vif->queues == NULL)
243 		goto out;
244 
245 	/* Aggregate tx and rx stats from each queue */
246 	for (index = 0; index < num_queues; ++index) {
247 		queue = &vif->queues[index];
248 		rx_bytes += queue->stats.rx_bytes;
249 		rx_packets += queue->stats.rx_packets;
250 		tx_bytes += queue->stats.tx_bytes;
251 		tx_packets += queue->stats.tx_packets;
252 	}
253 
254 out:
255 	vif->dev->stats.rx_bytes = rx_bytes;
256 	vif->dev->stats.rx_packets = rx_packets;
257 	vif->dev->stats.tx_bytes = tx_bytes;
258 	vif->dev->stats.tx_packets = tx_packets;
259 
260 	return &vif->dev->stats;
261 }
262 
263 static void xenvif_up(struct xenvif *vif)
264 {
265 	struct xenvif_queue *queue = NULL;
266 	unsigned int num_queues = vif->num_queues;
267 	unsigned int queue_index;
268 
269 	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
270 		queue = &vif->queues[queue_index];
271 		napi_enable(&queue->napi);
272 		enable_irq(queue->tx_irq);
273 		if (queue->tx_irq != queue->rx_irq)
274 			enable_irq(queue->rx_irq);
275 		xenvif_napi_schedule_or_enable_events(queue);
276 	}
277 }
278 
279 static void xenvif_down(struct xenvif *vif)
280 {
281 	struct xenvif_queue *queue = NULL;
282 	unsigned int num_queues = vif->num_queues;
283 	unsigned int queue_index;
284 
285 	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
286 		queue = &vif->queues[queue_index];
287 		disable_irq(queue->tx_irq);
288 		if (queue->tx_irq != queue->rx_irq)
289 			disable_irq(queue->rx_irq);
290 		napi_disable(&queue->napi);
291 		del_timer_sync(&queue->credit_timeout);
292 	}
293 }
294 
295 static int xenvif_open(struct net_device *dev)
296 {
297 	struct xenvif *vif = netdev_priv(dev);
298 	if (test_bit(VIF_STATUS_CONNECTED, &vif->status))
299 		xenvif_up(vif);
300 	netif_tx_start_all_queues(dev);
301 	return 0;
302 }
303 
304 static int xenvif_close(struct net_device *dev)
305 {
306 	struct xenvif *vif = netdev_priv(dev);
307 	if (test_bit(VIF_STATUS_CONNECTED, &vif->status))
308 		xenvif_down(vif);
309 	netif_tx_stop_all_queues(dev);
310 	return 0;
311 }
312 
313 static int xenvif_change_mtu(struct net_device *dev, int mtu)
314 {
315 	struct xenvif *vif = netdev_priv(dev);
316 	int max = vif->can_sg ? 65535 - VLAN_ETH_HLEN : ETH_DATA_LEN;
317 
318 	if (mtu > max)
319 		return -EINVAL;
320 	dev->mtu = mtu;
321 	return 0;
322 }
323 
324 static netdev_features_t xenvif_fix_features(struct net_device *dev,
325 	netdev_features_t features)
326 {
327 	struct xenvif *vif = netdev_priv(dev);
328 
329 	if (!vif->can_sg)
330 		features &= ~NETIF_F_SG;
331 	if (~(vif->gso_mask | vif->gso_prefix_mask) & GSO_BIT(TCPV4))
332 		features &= ~NETIF_F_TSO;
333 	if (~(vif->gso_mask | vif->gso_prefix_mask) & GSO_BIT(TCPV6))
334 		features &= ~NETIF_F_TSO6;
335 	if (!vif->ip_csum)
336 		features &= ~NETIF_F_IP_CSUM;
337 	if (!vif->ipv6_csum)
338 		features &= ~NETIF_F_IPV6_CSUM;
339 
340 	return features;
341 }
342 
343 static const struct xenvif_stat {
344 	char name[ETH_GSTRING_LEN];
345 	u16 offset;
346 } xenvif_stats[] = {
347 	{
348 		"rx_gso_checksum_fixup",
349 		offsetof(struct xenvif_stats, rx_gso_checksum_fixup)
350 	},
351 	/* If (sent != success + fail), there are probably packets never
352 	 * freed up properly!
353 	 */
354 	{
355 		"tx_zerocopy_sent",
356 		offsetof(struct xenvif_stats, tx_zerocopy_sent),
357 	},
358 	{
359 		"tx_zerocopy_success",
360 		offsetof(struct xenvif_stats, tx_zerocopy_success),
361 	},
362 	{
363 		"tx_zerocopy_fail",
364 		offsetof(struct xenvif_stats, tx_zerocopy_fail)
365 	},
366 	/* Number of packets exceeding MAX_SKB_FRAG slots. You should use
367 	 * a guest with the same MAX_SKB_FRAG
368 	 */
369 	{
370 		"tx_frag_overflow",
371 		offsetof(struct xenvif_stats, tx_frag_overflow)
372 	},
373 };
374 
375 static int xenvif_get_sset_count(struct net_device *dev, int string_set)
376 {
377 	switch (string_set) {
378 	case ETH_SS_STATS:
379 		return ARRAY_SIZE(xenvif_stats);
380 	default:
381 		return -EINVAL;
382 	}
383 }
384 
385 static void xenvif_get_ethtool_stats(struct net_device *dev,
386 				     struct ethtool_stats *stats, u64 * data)
387 {
388 	struct xenvif *vif = netdev_priv(dev);
389 	unsigned int num_queues = vif->num_queues;
390 	int i;
391 	unsigned int queue_index;
392 
393 	for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++) {
394 		unsigned long accum = 0;
395 		for (queue_index = 0; queue_index < num_queues; ++queue_index) {
396 			void *vif_stats = &vif->queues[queue_index].stats;
397 			accum += *(unsigned long *)(vif_stats + xenvif_stats[i].offset);
398 		}
399 		data[i] = accum;
400 	}
401 }
402 
403 static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
404 {
405 	int i;
406 
407 	switch (stringset) {
408 	case ETH_SS_STATS:
409 		for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
410 			memcpy(data + i * ETH_GSTRING_LEN,
411 			       xenvif_stats[i].name, ETH_GSTRING_LEN);
412 		break;
413 	}
414 }
415 
416 static const struct ethtool_ops xenvif_ethtool_ops = {
417 	.get_link	= ethtool_op_get_link,
418 
419 	.get_sset_count = xenvif_get_sset_count,
420 	.get_ethtool_stats = xenvif_get_ethtool_stats,
421 	.get_strings = xenvif_get_strings,
422 };
423 
424 static const struct net_device_ops xenvif_netdev_ops = {
425 	.ndo_select_queue = xenvif_select_queue,
426 	.ndo_start_xmit	= xenvif_start_xmit,
427 	.ndo_get_stats	= xenvif_get_stats,
428 	.ndo_open	= xenvif_open,
429 	.ndo_stop	= xenvif_close,
430 	.ndo_change_mtu	= xenvif_change_mtu,
431 	.ndo_fix_features = xenvif_fix_features,
432 	.ndo_set_mac_address = eth_mac_addr,
433 	.ndo_validate_addr   = eth_validate_addr,
434 };
435 
436 struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
437 			    unsigned int handle)
438 {
439 	int err;
440 	struct net_device *dev;
441 	struct xenvif *vif;
442 	char name[IFNAMSIZ] = {};
443 
444 	snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
445 	/* Allocate a netdev with the max. supported number of queues.
446 	 * When the guest selects the desired number, it will be updated
447 	 * via netif_set_real_num_*_queues().
448 	 */
449 	dev = alloc_netdev_mq(sizeof(struct xenvif), name, NET_NAME_UNKNOWN,
450 			      ether_setup, xenvif_max_queues);
451 	if (dev == NULL) {
452 		pr_warn("Could not allocate netdev for %s\n", name);
453 		return ERR_PTR(-ENOMEM);
454 	}
455 
456 	SET_NETDEV_DEV(dev, parent);
457 
458 	vif = netdev_priv(dev);
459 
460 	vif->domid  = domid;
461 	vif->handle = handle;
462 	vif->can_sg = 1;
463 	vif->ip_csum = 1;
464 	vif->dev = dev;
465 	vif->disabled = false;
466 	vif->drain_timeout = msecs_to_jiffies(rx_drain_timeout_msecs);
467 	vif->stall_timeout = msecs_to_jiffies(rx_stall_timeout_msecs);
468 
469 	/* Start out with no queues. */
470 	vif->queues = NULL;
471 	vif->num_queues = 0;
472 
473 	spin_lock_init(&vif->lock);
474 	INIT_LIST_HEAD(&vif->fe_mcast_addr);
475 
476 	dev->netdev_ops	= &xenvif_netdev_ops;
477 	dev->hw_features = NETIF_F_SG |
478 		NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
479 		NETIF_F_TSO | NETIF_F_TSO6;
480 	dev->features = dev->hw_features | NETIF_F_RXCSUM;
481 	dev->ethtool_ops = &xenvif_ethtool_ops;
482 
483 	dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
484 
485 	/*
486 	 * Initialise a dummy MAC address. We choose the numerically
487 	 * largest non-broadcast address to prevent the address getting
488 	 * stolen by an Ethernet bridge for STP purposes.
489 	 * (FE:FF:FF:FF:FF:FF)
490 	 */
491 	eth_broadcast_addr(dev->dev_addr);
492 	dev->dev_addr[0] &= ~0x01;
493 
494 	netif_carrier_off(dev);
495 
496 	err = register_netdev(dev);
497 	if (err) {
498 		netdev_warn(dev, "Could not register device: err=%d\n", err);
499 		free_netdev(dev);
500 		return ERR_PTR(err);
501 	}
502 
503 	netdev_dbg(dev, "Successfully created xenvif\n");
504 
505 	__module_get(THIS_MODULE);
506 
507 	return vif;
508 }
509 
510 int xenvif_init_queue(struct xenvif_queue *queue)
511 {
512 	int err, i;
513 
514 	queue->credit_bytes = queue->remaining_credit = ~0UL;
515 	queue->credit_usec  = 0UL;
516 	init_timer(&queue->credit_timeout);
517 	queue->credit_timeout.function = xenvif_tx_credit_callback;
518 	queue->credit_window_start = get_jiffies_64();
519 
520 	queue->rx_queue_max = XENVIF_RX_QUEUE_BYTES;
521 
522 	skb_queue_head_init(&queue->rx_queue);
523 	skb_queue_head_init(&queue->tx_queue);
524 
525 	queue->pending_cons = 0;
526 	queue->pending_prod = MAX_PENDING_REQS;
527 	for (i = 0; i < MAX_PENDING_REQS; ++i)
528 		queue->pending_ring[i] = i;
529 
530 	spin_lock_init(&queue->callback_lock);
531 	spin_lock_init(&queue->response_lock);
532 
533 	/* If ballooning is disabled, this will consume real memory, so you
534 	 * better enable it. The long term solution would be to use just a
535 	 * bunch of valid page descriptors, without dependency on ballooning
536 	 */
537 	err = gnttab_alloc_pages(MAX_PENDING_REQS,
538 				 queue->mmap_pages);
539 	if (err) {
540 		netdev_err(queue->vif->dev, "Could not reserve mmap_pages\n");
541 		return -ENOMEM;
542 	}
543 
544 	for (i = 0; i < MAX_PENDING_REQS; i++) {
545 		queue->pending_tx_info[i].callback_struct = (struct ubuf_info)
546 			{ .callback = xenvif_zerocopy_callback,
547 			  .ctx = NULL,
548 			  .desc = i };
549 		queue->grant_tx_handle[i] = NETBACK_INVALID_HANDLE;
550 	}
551 
552 	return 0;
553 }
554 
555 void xenvif_carrier_on(struct xenvif *vif)
556 {
557 	rtnl_lock();
558 	if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
559 		dev_set_mtu(vif->dev, ETH_DATA_LEN);
560 	netdev_update_features(vif->dev);
561 	set_bit(VIF_STATUS_CONNECTED, &vif->status);
562 	if (netif_running(vif->dev))
563 		xenvif_up(vif);
564 	rtnl_unlock();
565 }
566 
567 int xenvif_connect_ctrl(struct xenvif *vif, grant_ref_t ring_ref,
568 			unsigned int evtchn)
569 {
570 	struct net_device *dev = vif->dev;
571 	void *addr;
572 	struct xen_netif_ctrl_sring *shared;
573 	struct task_struct *task;
574 	int err = -ENOMEM;
575 
576 	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
577 				     &ring_ref, 1, &addr);
578 	if (err)
579 		goto err;
580 
581 	shared = (struct xen_netif_ctrl_sring *)addr;
582 	BACK_RING_INIT(&vif->ctrl, shared, XEN_PAGE_SIZE);
583 
584 	init_waitqueue_head(&vif->ctrl_wq);
585 
586 	err = bind_interdomain_evtchn_to_irqhandler(vif->domid, evtchn,
587 						    xenvif_ctrl_interrupt,
588 						    0, dev->name, vif);
589 	if (err < 0)
590 		goto err_unmap;
591 
592 	vif->ctrl_irq = err;
593 
594 	xenvif_init_hash(vif);
595 
596 	task = kthread_create(xenvif_ctrl_kthread, (void *)vif,
597 			      "%s-control", dev->name);
598 	if (IS_ERR(task)) {
599 		pr_warn("Could not allocate kthread for %s\n", dev->name);
600 		err = PTR_ERR(task);
601 		goto err_deinit;
602 	}
603 
604 	get_task_struct(task);
605 	vif->ctrl_task = task;
606 
607 	wake_up_process(vif->ctrl_task);
608 
609 	return 0;
610 
611 err_deinit:
612 	xenvif_deinit_hash(vif);
613 	unbind_from_irqhandler(vif->ctrl_irq, vif);
614 	vif->ctrl_irq = 0;
615 
616 err_unmap:
617 	xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
618 				vif->ctrl.sring);
619 	vif->ctrl.sring = NULL;
620 
621 err:
622 	return err;
623 }
624 
625 int xenvif_connect_data(struct xenvif_queue *queue,
626 			unsigned long tx_ring_ref,
627 			unsigned long rx_ring_ref,
628 			unsigned int tx_evtchn,
629 			unsigned int rx_evtchn)
630 {
631 	struct task_struct *task;
632 	int err = -ENOMEM;
633 
634 	BUG_ON(queue->tx_irq);
635 	BUG_ON(queue->task);
636 	BUG_ON(queue->dealloc_task);
637 
638 	err = xenvif_map_frontend_data_rings(queue, tx_ring_ref,
639 					     rx_ring_ref);
640 	if (err < 0)
641 		goto err;
642 
643 	init_waitqueue_head(&queue->wq);
644 	init_waitqueue_head(&queue->dealloc_wq);
645 	atomic_set(&queue->inflight_packets, 0);
646 
647 	netif_napi_add(queue->vif->dev, &queue->napi, xenvif_poll,
648 			XENVIF_NAPI_WEIGHT);
649 
650 	if (tx_evtchn == rx_evtchn) {
651 		/* feature-split-event-channels == 0 */
652 		err = bind_interdomain_evtchn_to_irqhandler(
653 			queue->vif->domid, tx_evtchn, xenvif_interrupt, 0,
654 			queue->name, queue);
655 		if (err < 0)
656 			goto err_unmap;
657 		queue->tx_irq = queue->rx_irq = err;
658 		disable_irq(queue->tx_irq);
659 	} else {
660 		/* feature-split-event-channels == 1 */
661 		snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
662 			 "%s-tx", queue->name);
663 		err = bind_interdomain_evtchn_to_irqhandler(
664 			queue->vif->domid, tx_evtchn, xenvif_tx_interrupt, 0,
665 			queue->tx_irq_name, queue);
666 		if (err < 0)
667 			goto err_unmap;
668 		queue->tx_irq = err;
669 		disable_irq(queue->tx_irq);
670 
671 		snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
672 			 "%s-rx", queue->name);
673 		err = bind_interdomain_evtchn_to_irqhandler(
674 			queue->vif->domid, rx_evtchn, xenvif_rx_interrupt, 0,
675 			queue->rx_irq_name, queue);
676 		if (err < 0)
677 			goto err_tx_unbind;
678 		queue->rx_irq = err;
679 		disable_irq(queue->rx_irq);
680 	}
681 
682 	queue->stalled = true;
683 
684 	task = kthread_create(xenvif_kthread_guest_rx,
685 			      (void *)queue, "%s-guest-rx", queue->name);
686 	if (IS_ERR(task)) {
687 		pr_warn("Could not allocate kthread for %s\n", queue->name);
688 		err = PTR_ERR(task);
689 		goto err_rx_unbind;
690 	}
691 	queue->task = task;
692 	get_task_struct(task);
693 
694 	task = kthread_create(xenvif_dealloc_kthread,
695 			      (void *)queue, "%s-dealloc", queue->name);
696 	if (IS_ERR(task)) {
697 		pr_warn("Could not allocate kthread for %s\n", queue->name);
698 		err = PTR_ERR(task);
699 		goto err_rx_unbind;
700 	}
701 	queue->dealloc_task = task;
702 
703 	wake_up_process(queue->task);
704 	wake_up_process(queue->dealloc_task);
705 
706 	return 0;
707 
708 err_rx_unbind:
709 	unbind_from_irqhandler(queue->rx_irq, queue);
710 	queue->rx_irq = 0;
711 err_tx_unbind:
712 	unbind_from_irqhandler(queue->tx_irq, queue);
713 	queue->tx_irq = 0;
714 err_unmap:
715 	xenvif_unmap_frontend_data_rings(queue);
716 	netif_napi_del(&queue->napi);
717 err:
718 	module_put(THIS_MODULE);
719 	return err;
720 }
721 
722 void xenvif_carrier_off(struct xenvif *vif)
723 {
724 	struct net_device *dev = vif->dev;
725 
726 	rtnl_lock();
727 	if (test_and_clear_bit(VIF_STATUS_CONNECTED, &vif->status)) {
728 		netif_carrier_off(dev); /* discard queued packets */
729 		if (netif_running(dev))
730 			xenvif_down(vif);
731 	}
732 	rtnl_unlock();
733 }
734 
735 void xenvif_disconnect_data(struct xenvif *vif)
736 {
737 	struct xenvif_queue *queue = NULL;
738 	unsigned int num_queues = vif->num_queues;
739 	unsigned int queue_index;
740 
741 	xenvif_carrier_off(vif);
742 
743 	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
744 		queue = &vif->queues[queue_index];
745 
746 		netif_napi_del(&queue->napi);
747 
748 		if (queue->task) {
749 			kthread_stop(queue->task);
750 			put_task_struct(queue->task);
751 			queue->task = NULL;
752 		}
753 
754 		if (queue->dealloc_task) {
755 			kthread_stop(queue->dealloc_task);
756 			queue->dealloc_task = NULL;
757 		}
758 
759 		if (queue->tx_irq) {
760 			if (queue->tx_irq == queue->rx_irq)
761 				unbind_from_irqhandler(queue->tx_irq, queue);
762 			else {
763 				unbind_from_irqhandler(queue->tx_irq, queue);
764 				unbind_from_irqhandler(queue->rx_irq, queue);
765 			}
766 			queue->tx_irq = 0;
767 		}
768 
769 		xenvif_unmap_frontend_data_rings(queue);
770 	}
771 
772 	xenvif_mcast_addr_list_free(vif);
773 }
774 
775 void xenvif_disconnect_ctrl(struct xenvif *vif)
776 {
777 	if (vif->ctrl_task) {
778 		kthread_stop(vif->ctrl_task);
779 		put_task_struct(vif->ctrl_task);
780 		vif->ctrl_task = NULL;
781 	}
782 
783 	if (vif->ctrl_irq) {
784 		xenvif_deinit_hash(vif);
785 		unbind_from_irqhandler(vif->ctrl_irq, vif);
786 		vif->ctrl_irq = 0;
787 	}
788 
789 	if (vif->ctrl.sring) {
790 		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
791 					vif->ctrl.sring);
792 		vif->ctrl.sring = NULL;
793 	}
794 }
795 
796 /* Reverse the relevant parts of xenvif_init_queue().
797  * Used for queue teardown from xenvif_free(), and on the
798  * error handling paths in xenbus.c:connect().
799  */
800 void xenvif_deinit_queue(struct xenvif_queue *queue)
801 {
802 	gnttab_free_pages(MAX_PENDING_REQS, queue->mmap_pages);
803 }
804 
805 void xenvif_free(struct xenvif *vif)
806 {
807 	struct xenvif_queue *queues = vif->queues;
808 	unsigned int num_queues = vif->num_queues;
809 	unsigned int queue_index;
810 
811 	unregister_netdev(vif->dev);
812 	free_netdev(vif->dev);
813 
814 	for (queue_index = 0; queue_index < num_queues; ++queue_index)
815 		xenvif_deinit_queue(&queues[queue_index]);
816 	vfree(queues);
817 
818 	module_put(THIS_MODULE);
819 }
820