[deliverable/linux.git] / drivers / net / xen-netback / interface.c

/*
 * Network-device interface management.
 *
 * Copyright (c) 2004-2005, Keir Fraser
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation; or, when distributed
 * separately from the Linux kernel or incorporated into other
 * software packages, subject to the following license:
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this source file (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#include "common.h"

#include <linux/ethtool.h>
#include <linux/rtnetlink.h>
#include <linux/if_vlan.h>

#include <xen/events.h>
#include <asm/xen/hypercall.h>

#define XENVIF_QUEUE_LENGTH 32

void xenvif_get(struct xenvif *vif)
{
	atomic_inc(&vif->refcnt);
}

void xenvif_put(struct xenvif *vif)
{
	if (atomic_dec_and_test(&vif->refcnt))
		wake_up(&vif->waiting_to_free);
}

int xenvif_schedulable(struct xenvif *vif)
{
	return netif_running(vif->dev) && netif_carrier_ok(vif->dev);
}

static int xenvif_rx_schedulable(struct xenvif *vif)
{
	return xenvif_schedulable(vif) && !xen_netbk_rx_ring_full(vif);
}

static irqreturn_t xenvif_interrupt(int irq, void *dev_id)
{
	struct xenvif *vif = dev_id;

	if (vif->netbk == NULL)
		return IRQ_NONE;

	xen_netbk_schedule_xenvif(vif);

	if (xenvif_rx_schedulable(vif))
		netif_wake_queue(vif->dev);

	return IRQ_HANDLED;
}

static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct xenvif *vif = netdev_priv(dev);

	BUG_ON(skb->dev != dev);

	if (vif->netbk == NULL)
		goto drop;

	/* Drop the packet if the target domain has no receive buffers. */
	if (!xenvif_rx_schedulable(vif))
		goto drop;

	/* Reserve ring slots for the worst-case number of fragments. */
	vif->rx_req_cons_peek += xen_netbk_count_skb_slots(vif, skb);
	xenvif_get(vif);

	if (vif->can_queue && xen_netbk_must_stop_queue(vif))
		netif_stop_queue(dev);

	xen_netbk_queue_tx_skb(vif, skb);

	return NETDEV_TX_OK;

 drop:
	vif->dev->stats.tx_dropped++;
	dev_kfree_skb(skb);
	return NETDEV_TX_OK;
}

void xenvif_receive_skb(struct xenvif *vif, struct sk_buff *skb)
{
	netif_rx_ni(skb);
}

void xenvif_notify_tx_completion(struct xenvif *vif)
{
	if (netif_queue_stopped(vif->dev) && xenvif_rx_schedulable(vif))
		netif_wake_queue(vif->dev);
}

static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
{
	struct xenvif *vif = netdev_priv(dev);
	return &vif->dev->stats;
}

static void xenvif_up(struct xenvif *vif)
{
	xen_netbk_add_xenvif(vif);
	enable_irq(vif->irq);
	xen_netbk_check_rx_xenvif(vif);
}

static void xenvif_down(struct xenvif *vif)
{
	disable_irq(vif->irq);
	del_timer_sync(&vif->credit_timeout);
	xen_netbk_deschedule_xenvif(vif);
	xen_netbk_remove_xenvif(vif);
}

static int xenvif_open(struct net_device *dev)
{
	struct xenvif *vif = netdev_priv(dev);
	if (netif_carrier_ok(dev))
		xenvif_up(vif);
	netif_start_queue(dev);
	return 0;
}

static int xenvif_close(struct net_device *dev)
{
	struct xenvif *vif = netdev_priv(dev);
	if (netif_carrier_ok(dev))
		xenvif_down(vif);
	netif_stop_queue(dev);
	return 0;
}

static int xenvif_change_mtu(struct net_device *dev, int mtu)
{
	struct xenvif *vif = netdev_priv(dev);
	int max = vif->can_sg ? 65535 - VLAN_ETH_HLEN : ETH_DATA_LEN;

	if (mtu > max)
		return -EINVAL;
	dev->mtu = mtu;
	return 0;
}

static netdev_features_t xenvif_fix_features(struct net_device *dev,
	netdev_features_t features)
{
	struct xenvif *vif = netdev_priv(dev);

	if (!vif->can_sg)
		features &= ~NETIF_F_SG;
	if (!vif->gso && !vif->gso_prefix)
		features &= ~NETIF_F_TSO;
	if (!vif->csum)
		features &= ~NETIF_F_IP_CSUM;

	return features;
}

static const struct xenvif_stat {
	char name[ETH_GSTRING_LEN];
	u16 offset;
} xenvif_stats[] = {
	{
		"rx_gso_checksum_fixup",
		offsetof(struct xenvif, rx_gso_checksum_fixup)
	},
};

static int xenvif_get_sset_count(struct net_device *dev, int string_set)
{
	switch (string_set) {
	case ETH_SS_STATS:
		return ARRAY_SIZE(xenvif_stats);
	default:
		return -EINVAL;
	}
}

static void xenvif_get_ethtool_stats(struct net_device *dev,
				     struct ethtool_stats *stats, u64 * data)
{
	void *vif = netdev_priv(dev);
	int i;

	for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
		data[i] = *(unsigned long *)(vif + xenvif_stats[i].offset);
}

static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
{
	int i;

	switch (stringset) {
	case ETH_SS_STATS:
		for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
			memcpy(data + i * ETH_GSTRING_LEN,
			       xenvif_stats[i].name, ETH_GSTRING_LEN);
		break;
	}
}

static const struct ethtool_ops xenvif_ethtool_ops = {
	.get_link	= ethtool_op_get_link,

	.get_sset_count = xenvif_get_sset_count,
	.get_ethtool_stats = xenvif_get_ethtool_stats,
	.get_strings = xenvif_get_strings,
};

static const struct net_device_ops xenvif_netdev_ops = {
	.ndo_start_xmit	= xenvif_start_xmit,
	.ndo_get_stats	= xenvif_get_stats,
	.ndo_open	= xenvif_open,
	.ndo_stop	= xenvif_close,
	.ndo_change_mtu	= xenvif_change_mtu,
	.ndo_fix_features = xenvif_fix_features,
	.ndo_set_mac_address = eth_mac_addr,
	.ndo_validate_addr   = eth_validate_addr,
};

struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
			    unsigned int handle)
{
	int err;
	struct net_device *dev;
	struct xenvif *vif;
	char name[IFNAMSIZ] = {};

	snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
	dev = alloc_netdev(sizeof(struct xenvif), name, ether_setup);
	if (dev == NULL) {
		pr_warn("Could not allocate netdev\n");
		return ERR_PTR(-ENOMEM);
	}

	SET_NETDEV_DEV(dev, parent);

	vif = netdev_priv(dev);
	vif->domid  = domid;
	vif->handle = handle;
	vif->netbk  = NULL;
	vif->can_sg = 1;
	vif->csum = 1;
	atomic_set(&vif->refcnt, 1);
	init_waitqueue_head(&vif->waiting_to_free);
	vif->dev = dev;
	INIT_LIST_HEAD(&vif->schedule_list);
	INIT_LIST_HEAD(&vif->notify_list);

	vif->credit_bytes = vif->remaining_credit = ~0UL;
	vif->credit_usec  = 0UL;
	init_timer(&vif->credit_timeout);
	/* Initialize 'expires' now: it's used to track the credit window. */
	vif->credit_timeout.expires = jiffies;

	dev->netdev_ops	= &xenvif_netdev_ops;
	dev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO;
	dev->features = dev->hw_features;
	SET_ETHTOOL_OPS(dev, &xenvif_ethtool_ops);

	dev->tx_queue_len = XENVIF_QUEUE_LENGTH;

	/*
	 * Initialise a dummy MAC address. We choose the numerically
	 * largest non-broadcast address to prevent the address getting
	 * stolen by an Ethernet bridge for STP purposes.
	 * (FE:FF:FF:FF:FF:FF)
	 */
	memset(dev->dev_addr, 0xFF, ETH_ALEN);
	dev->dev_addr[0] &= ~0x01;

	netif_carrier_off(dev);

	err = register_netdev(dev);
	if (err) {
		netdev_warn(dev, "Could not register device: err=%d\n", err);
		free_netdev(dev);
		return ERR_PTR(err);
	}

	netdev_dbg(dev, "Successfully created xenvif\n");
	return vif;
}

int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
		   unsigned long rx_ring_ref, unsigned int evtchn)
{
	int err = -ENOMEM;

	/* Already connected through? */
	if (vif->irq)
		return 0;

	__module_get(THIS_MODULE);

	err = xen_netbk_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref);
	if (err < 0)
		goto err;

	err = bind_interdomain_evtchn_to_irqhandler(
		vif->domid, evtchn, xenvif_interrupt, 0,
		vif->dev->name, vif);
	if (err < 0)
		goto err_unmap;
	vif->irq = err;
	disable_irq(vif->irq);

	xenvif_get(vif);

	rtnl_lock();
	if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
		dev_set_mtu(vif->dev, ETH_DATA_LEN);
	netdev_update_features(vif->dev);
	netif_carrier_on(vif->dev);
	if (netif_running(vif->dev))
		xenvif_up(vif);
	rtnl_unlock();

	return 0;
err_unmap:
	xen_netbk_unmap_frontend_rings(vif);
err:
	module_put(THIS_MODULE);
	return err;
}

void xenvif_carrier_off(struct xenvif *vif)
{
	struct net_device *dev = vif->dev;

	rtnl_lock();
	netif_carrier_off(dev); /* discard queued packets */
	if (netif_running(dev))
		xenvif_down(vif);
	rtnl_unlock();
	xenvif_put(vif);
}

void xenvif_disconnect(struct xenvif *vif)
{
	/* Disconnect funtion might get called by generic framework
	 * even before vif connects, so we need to check if we really
	 * need to do a module_put.
	 */
	int need_module_put = 0;

	if (netif_carrier_ok(vif->dev))
		xenvif_carrier_off(vif);

	atomic_dec(&vif->refcnt);
	wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0);

	if (vif->irq) {
		unbind_from_irqhandler(vif->irq, vif);
		/* vif->irq is valid, we had a module_get in
		 * xenvif_connect.
		 */
		need_module_put = 1;
	}

	unregister_netdev(vif->dev);

	xen_netbk_unmap_frontend_rings(vif);

	free_netdev(vif->dev);

	if (need_module_put)
		module_put(THIS_MODULE);
}
Commit	Line	Data
f942dc25 IC	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/ethtool.h>
	34	#include <linux/rtnetlink.h>
	35	#include <linux/if_vlan.h>
	36
	37	#include <xen/events.h>
	38	#include <asm/xen/hypercall.h>
	39
	40	#define XENVIF_QUEUE_LENGTH 32
	41
	42	void xenvif_get(struct xenvif *vif)
	43	{
	44	atomic_inc(&vif->refcnt);
	45	}
	46
	47	void xenvif_put(struct xenvif *vif)
	48	{
	49	if (atomic_dec_and_test(&vif->refcnt))
	50	wake_up(&vif->waiting_to_free);
	51	}
	52
	53	int xenvif_schedulable(struct xenvif *vif)
	54	{
	55	return netif_running(vif->dev) && netif_carrier_ok(vif->dev);
	56	}
	57
	58	static int xenvif_rx_schedulable(struct xenvif *vif)
	59	{
	60	return xenvif_schedulable(vif) && !xen_netbk_rx_ring_full(vif);
	61	}
	62
	63	static irqreturn_t xenvif_interrupt(int irq, void *dev_id)
	64	{
65	struct xenvif *vif = dev_id;
66
67	if (vif->netbk == NULL)
68	return IRQ_NONE;
69
70	xen_netbk_schedule_xenvif(vif);
71
72	if (xenvif_rx_schedulable(vif))
73	netif_wake_queue(vif->dev);
74
75	return IRQ_HANDLED;
76	}
77
78	static int xenvif_start_xmit(struct sk_buff skb, struct net_device dev)
79	{
80	struct xenvif *vif = netdev_priv(dev);
81
82	BUG_ON(skb->dev != dev);
83
84	if (vif->netbk == NULL)
85	goto drop;
86
87	/* Drop the packet if the target domain has no receive buffers. */
88	if (!xenvif_rx_schedulable(vif))
89	goto drop;
90
91	/* Reserve ring slots for the worst-case number of fragments. */
92	vif->rx_req_cons_peek += xen_netbk_count_skb_slots(vif, skb);
93	xenvif_get(vif);
94
95	if (vif->can_queue && xen_netbk_must_stop_queue(vif))
96	netif_stop_queue(dev);
97
98	xen_netbk_queue_tx_skb(vif, skb);
99
100	return NETDEV_TX_OK;
101
102	drop:
103	vif->dev->stats.tx_dropped++;
104	dev_kfree_skb(skb);
105	return NETDEV_TX_OK;
106	}
107
108	void xenvif_receive_skb(struct xenvif vif, struct sk_buff skb)
109	{
110	netif_rx_ni(skb);
111	}
112
113	void xenvif_notify_tx_completion(struct xenvif *vif)
114	{
115	if (netif_queue_stopped(vif->dev) && xenvif_rx_schedulable(vif))
116	netif_wake_queue(vif->dev);
117	}
118
119	static struct net_device_stats xenvif_get_stats(struct net_device dev)
120	{
121	struct xenvif *vif = netdev_priv(dev);
122	return &vif->dev->stats;
123	}
124
125	static void xenvif_up(struct xenvif *vif)
126	{
127	xen_netbk_add_xenvif(vif);
128	enable_irq(vif->irq);
129	xen_netbk_check_rx_xenvif(vif);
130	}
131
132	static void xenvif_down(struct xenvif *vif)
133	{
134	disable_irq(vif->irq);
3e55f8b3	135	del_timer_sync(&vif->credit_timeout);
f942dc25 IC	136	xen_netbk_deschedule_xenvif(vif);
	137	xen_netbk_remove_xenvif(vif);
	138	}
	139
	140	static int xenvif_open(struct net_device *dev)
	141	{
	142	struct xenvif *vif = netdev_priv(dev);
	143	if (netif_carrier_ok(dev))
	144	xenvif_up(vif);
	145	netif_start_queue(dev);
	146	return 0;
	147	}
	148
	149	static int xenvif_close(struct net_device *dev)
	150	{
	151	struct xenvif *vif = netdev_priv(dev);
	152	if (netif_carrier_ok(dev))
	153	xenvif_down(vif);
	154	netif_stop_queue(dev);
	155	return 0;
	156	}
	157
	158	static int xenvif_change_mtu(struct net_device *dev, int mtu)
	159	{
	160	struct xenvif *vif = netdev_priv(dev);
	161	int max = vif->can_sg ? 65535 - VLAN_ETH_HLEN : ETH_DATA_LEN;
	162
	163	if (mtu > max)
	164	return -EINVAL;
	165	dev->mtu = mtu;
	166	return 0;
	167	}
	168
c8f44aff MM	169	static netdev_features_t xenvif_fix_features(struct net_device *dev,
c8f44aff MM	170	netdev_features_t features)
f942dc25 IC	171	{
f942dc25 IC	172	struct xenvif *vif = netdev_priv(dev);
f942dc25	173
47103041 MM	174	if (!vif->can_sg)
	175	features &= ~NETIF_F_SG;
	176	if (!vif->gso && !vif->gso_prefix)
	177	features &= ~NETIF_F_TSO;
	178	if (!vif->csum)
	179	features &= ~NETIF_F_IP_CSUM;
f942dc25	180
47103041	181	return features;
f942dc25 IC	182	}
	183
	184	static const struct xenvif_stat {
	185	char name[ETH_GSTRING_LEN];
	186	u16 offset;
	187	} xenvif_stats[] = {
	188	{
	189	"rx_gso_checksum_fixup",
	190	offsetof(struct xenvif, rx_gso_checksum_fixup)
	191	},
	192	};
	193
	194	static int xenvif_get_sset_count(struct net_device *dev, int string_set)
	195	{
	196	switch (string_set) {
	197	case ETH_SS_STATS:
	198	return ARRAY_SIZE(xenvif_stats);
	199	default:
	200	return -EINVAL;
	201	}
	202	}
	203
	204	static void xenvif_get_ethtool_stats(struct net_device *dev,
	205	struct ethtool_stats stats, u64 data)
	206	{
	207	void *vif = netdev_priv(dev);
	208	int i;
	209
	210	for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
	211	data[i] = (unsigned long )(vif + xenvif_stats[i].offset);
	212	}
	213
	214	static void xenvif_get_strings(struct net_device dev, u32 stringset, u8 data)
	215	{
	216	int i;
	217
	218	switch (stringset) {
	219	case ETH_SS_STATS:
	220	for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
	221	memcpy(data + i * ETH_GSTRING_LEN,
	222	xenvif_stats[i].name, ETH_GSTRING_LEN);
	223	break;
	224	}
	225	}
	226
813abbba	227	static const struct ethtool_ops xenvif_ethtool_ops = {
f942dc25 IC	228	.get_link = ethtool_op_get_link,
	229
	230	.get_sset_count = xenvif_get_sset_count,
	231	.get_ethtool_stats = xenvif_get_ethtool_stats,
	232	.get_strings = xenvif_get_strings,
	233	};
	234
813abbba	235	static const struct net_device_ops xenvif_netdev_ops = {
f942dc25 IC	236	.ndo_start_xmit = xenvif_start_xmit,
	237	.ndo_get_stats = xenvif_get_stats,
	238	.ndo_open = xenvif_open,
	239	.ndo_stop = xenvif_close,
	240	.ndo_change_mtu = xenvif_change_mtu,
47103041	241	.ndo_fix_features = xenvif_fix_features,
4a633a60 MW	242	.ndo_set_mac_address = eth_mac_addr,
4a633a60 MW	243	.ndo_validate_addr = eth_validate_addr,
f942dc25 IC	244	};
	245
	246	struct xenvif xenvif_alloc(struct device parent, domid_t domid,
	247	unsigned int handle)
	248	{
	249	int err;
	250	struct net_device *dev;
	251	struct xenvif *vif;
	252	char name[IFNAMSIZ] = {};
	253
	254	snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
	255	dev = alloc_netdev(sizeof(struct xenvif), name, ether_setup);
	256	if (dev == NULL) {
	257	pr_warn("Could not allocate netdev\n");
	258	return ERR_PTR(-ENOMEM);
	259	}
	260
	261	SET_NETDEV_DEV(dev, parent);
	262
	263	vif = netdev_priv(dev);
	264	vif->domid = domid;
	265	vif->handle = handle;
	266	vif->netbk = NULL;
	267	vif->can_sg = 1;
	268	vif->csum = 1;
	269	atomic_set(&vif->refcnt, 1);
	270	init_waitqueue_head(&vif->waiting_to_free);
	271	vif->dev = dev;
	272	INIT_LIST_HEAD(&vif->schedule_list);
	273	INIT_LIST_HEAD(&vif->notify_list);
	274
	275	vif->credit_bytes = vif->remaining_credit = ~0UL;
	276	vif->credit_usec = 0UL;
	277	init_timer(&vif->credit_timeout);
	278	/* Initialize 'expires' now: it's used to track the credit window. */
	279	vif->credit_timeout.expires = jiffies;
	280
	281	dev->netdev_ops = &xenvif_netdev_ops;
47103041 MM	282	dev->hw_features = NETIF_F_SG \| NETIF_F_IP_CSUM \| NETIF_F_TSO;
47103041 MM	283	dev->features = dev->hw_features;
f942dc25 IC	284	SET_ETHTOOL_OPS(dev, &xenvif_ethtool_ops);
	285
	286	dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
	287
	288	/*
	289	* Initialise a dummy MAC address. We choose the numerically
	290	* largest non-broadcast address to prevent the address getting
	291	* stolen by an Ethernet bridge for STP purposes.
	292	* (FE:FF:FF:FF:FF:FF)
	293	*/
	294	memset(dev->dev_addr, 0xFF, ETH_ALEN);
	295	dev->dev_addr[0] &= ~0x01;
	296
	297	netif_carrier_off(dev);
	298
	299	err = register_netdev(dev);
	300	if (err) {
	301	netdev_warn(dev, "Could not register device: err=%d\n", err);
	302	free_netdev(dev);
	303	return ERR_PTR(err);
	304	}
	305
	306	netdev_dbg(dev, "Successfully created xenvif\n");
	307	return vif;
	308	}
	309
	310	int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
	311	unsigned long rx_ring_ref, unsigned int evtchn)
	312	{
	313	int err = -ENOMEM;
	314
	315	/* Already connected through? */
	316	if (vif->irq)
	317	return 0;
	318
b103f358 WL	319	__module_get(THIS_MODULE);
b103f358 WL	320
f942dc25 IC	321	err = xen_netbk_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref);
	322	if (err < 0)
	323	goto err;
	324
	325	err = bind_interdomain_evtchn_to_irqhandler(
	326	vif->domid, evtchn, xenvif_interrupt, 0,
	327	vif->dev->name, vif);
	328	if (err < 0)
	329	goto err_unmap;
	330	vif->irq = err;
	331	disable_irq(vif->irq);
	332
	333	xenvif_get(vif);
	334
	335	rtnl_lock();
47103041 MM	336	if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
	337	dev_set_mtu(vif->dev, ETH_DATA_LEN);
	338	netdev_update_features(vif->dev);
	339	netif_carrier_on(vif->dev);
d0e5d832 DV	340	if (netif_running(vif->dev))
d0e5d832 DV	341	xenvif_up(vif);
f942dc25 IC	342	rtnl_unlock();
	343
	344	return 0;
	345	err_unmap:
	346	xen_netbk_unmap_frontend_rings(vif);
	347	err:
b103f358	348	module_put(THIS_MODULE);
f942dc25 IC	349	return err;
	350	}
	351
48856286	352	void xenvif_carrier_off(struct xenvif *vif)
f942dc25 IC	353	{
f942dc25 IC	354	struct net_device *dev = vif->dev;
48856286 IC	355
	356	rtnl_lock();
	357	netif_carrier_off(dev); /* discard queued packets */
	358	if (netif_running(dev))
	359	xenvif_down(vif);
	360	rtnl_unlock();
	361	xenvif_put(vif);
	362	}
	363
	364	void xenvif_disconnect(struct xenvif *vif)
	365	{
b103f358 WL	366	/* Disconnect funtion might get called by generic framework
	367	* even before vif connects, so we need to check if we really
	368	* need to do a module_put.
	369	*/
	370	int need_module_put = 0;
	371
48856286 IC	372	if (netif_carrier_ok(vif->dev))
48856286 IC	373	xenvif_carrier_off(vif);
f942dc25 IC	374
	375	atomic_dec(&vif->refcnt);
	376	wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0);
	377
b103f358	378	if (vif->irq) {
f942dc25	379	unbind_from_irqhandler(vif->irq, vif);
b103f358 WL	380	/* vif->irq is valid, we had a module_get in
	381	* xenvif_connect.
	382	*/
	383	need_module_put = 1;
	384	}
f942dc25 IC	385
	386	unregister_netdev(vif->dev);
	387
	388	xen_netbk_unmap_frontend_rings(vif);
	389
	390	free_netdev(vif->dev);
b103f358 WL	391
	392	if (need_module_put)
	393	module_put(THIS_MODULE);
f942dc25	394	}