[net-next-2.6.git] / drivers / net / virtio_net.c

/* A simple network driver using virtio.
 *
 * Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
//#define DEBUG
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/module.h>
#include <linux/virtio.h>
#include <linux/virtio_net.h>
#include <linux/scatterlist.h>

static int napi_weight = 128;
module_param(napi_weight, int, 0444);

static int csum = 1, gso = 1;
module_param(csum, bool, 0444);
module_param(gso, bool, 0444);

/* FIXME: MTU in config. */
#define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN)

struct virtnet_info
{
	struct virtio_device *vdev;
	struct virtqueue *rvq, *svq;
	struct net_device *dev;
	struct napi_struct napi;

	/* Number of input buffers, and max we've ever had. */
	unsigned int num, max;

	/* Receive & send queues. */
	struct sk_buff_head recv;
	struct sk_buff_head send;
};

static inline struct virtio_net_hdr *skb_vnet_hdr(struct sk_buff *skb)
{
	return (struct virtio_net_hdr *)skb->cb;
}

static inline void vnet_hdr_to_sg(struct scatterlist *sg, struct sk_buff *skb)
{
	sg_init_one(sg, skb_vnet_hdr(skb), sizeof(struct virtio_net_hdr));
}

static void skb_xmit_done(struct virtqueue *svq)
{
	struct virtnet_info *vi = svq->vdev->priv;

	/* Suppress further interrupts. */
	svq->vq_ops->disable_cb(svq);
	/* We were waiting for more output buffers. */
	netif_wake_queue(vi->dev);
}

static void receive_skb(struct net_device *dev, struct sk_buff *skb,
			unsigned len)
{
	struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);

	if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
		pr_debug("%s: short packet %i\n", dev->name, len);
		dev->stats.rx_length_errors++;
		goto drop;
	}
	len -= sizeof(struct virtio_net_hdr);
	BUG_ON(len > MAX_PACKET_LEN);

	skb_trim(skb, len);
	skb->protocol = eth_type_trans(skb, dev);
	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
		 ntohs(skb->protocol), skb->len, skb->pkt_type);
	dev->stats.rx_bytes += skb->len;
	dev->stats.rx_packets++;

	if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
		pr_debug("Needs csum!\n");
		if (!skb_partial_csum_set(skb,hdr->csum_start,hdr->csum_offset))
			goto frame_err;
	}

	if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
		pr_debug("GSO!\n");
		switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
		case VIRTIO_NET_HDR_GSO_TCPV4:
			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
			break;
		case VIRTIO_NET_HDR_GSO_UDP:
			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
			break;
		case VIRTIO_NET_HDR_GSO_TCPV6:
			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
			break;
		default:
			if (net_ratelimit())
				printk(KERN_WARNING "%s: bad gso type %u.\n",
				       dev->name, hdr->gso_type);
			goto frame_err;
		}

		if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
			skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;

		skb_shinfo(skb)->gso_size = hdr->gso_size;
		if (skb_shinfo(skb)->gso_size == 0) {
			if (net_ratelimit())
				printk(KERN_WARNING "%s: zero gso size.\n",
				       dev->name);
			goto frame_err;
		}

		/* Header must be checked, and gso_segs computed. */
		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
		skb_shinfo(skb)->gso_segs = 0;
	}

	netif_receive_skb(skb);
	return;

frame_err:
	dev->stats.rx_frame_errors++;
drop:
	dev_kfree_skb(skb);
}

static void try_fill_recv(struct virtnet_info *vi)
{
	struct sk_buff *skb;
	struct scatterlist sg[1+MAX_SKB_FRAGS];
	int num, err;

	sg_init_table(sg, 1+MAX_SKB_FRAGS);
	for (;;) {
		skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
		if (unlikely(!skb))
			break;

		skb_put(skb, MAX_PACKET_LEN);
		vnet_hdr_to_sg(sg, skb);
		num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
		skb_queue_head(&vi->recv, skb);

		err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
		if (err) {
			skb_unlink(skb, &vi->recv);
			kfree_skb(skb);
			break;
		}
		vi->num++;
	}
	if (unlikely(vi->num > vi->max))
		vi->max = vi->num;
	vi->rvq->vq_ops->kick(vi->rvq);
}

static void skb_recv_done(struct virtqueue *rvq)
{
	struct virtnet_info *vi = rvq->vdev->priv;
	/* Schedule NAPI, Suppress further interrupts if successful. */
	if (netif_rx_schedule_prep(vi->dev, &vi->napi)) {
		rvq->vq_ops->disable_cb(rvq);
		__netif_rx_schedule(vi->dev, &vi->napi);
	}
}

static int virtnet_poll(struct napi_struct *napi, int budget)
{
	struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
	struct sk_buff *skb = NULL;
	unsigned int len, received = 0;

again:
	while (received < budget &&
	       (skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
		__skb_unlink(skb, &vi->recv);
		receive_skb(vi->dev, skb, len);
		vi->num--;
		received++;
	}

	/* FIXME: If we oom and completely run out of inbufs, we need
	 * to start a timer trying to fill more. */
	if (vi->num < vi->max / 2)
		try_fill_recv(vi);

	/* Out of packets? */
	if (received < budget) {
		netif_rx_complete(vi->dev, napi);
		if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq))
		    && napi_schedule_prep(napi)) {
			vi->rvq->vq_ops->disable_cb(vi->rvq);
			__netif_rx_schedule(vi->dev, napi);
			goto again;
		}
	}

	return received;
}

static void free_old_xmit_skbs(struct virtnet_info *vi)
{
	struct sk_buff *skb;
	unsigned int len;

	while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
		pr_debug("Sent skb %p\n", skb);
		__skb_unlink(skb, &vi->send);
		vi->dev->stats.tx_bytes += skb->len;
		vi->dev->stats.tx_packets++;
		kfree_skb(skb);
	}
}

static int start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct virtnet_info *vi = netdev_priv(dev);
	int num, err;
	struct scatterlist sg[1+MAX_SKB_FRAGS];
	struct virtio_net_hdr *hdr;
	const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;

	sg_init_table(sg, 1+MAX_SKB_FRAGS);

	pr_debug("%s: xmit %p " MAC_FMT "\n", dev->name, skb,
		 dest[0], dest[1], dest[2],
		 dest[3], dest[4], dest[5]);

	/* Encode metadata header at front. */
	hdr = skb_vnet_hdr(skb);
	if (skb->ip_summed == CHECKSUM_PARTIAL) {
		hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
		hdr->csum_start = skb->csum_start - skb_headroom(skb);
		hdr->csum_offset = skb->csum_offset;
	} else {
		hdr->flags = 0;
		hdr->csum_offset = hdr->csum_start = 0;
	}

	if (skb_is_gso(skb)) {
		hdr->hdr_len = skb_transport_header(skb) - skb->data;
		hdr->gso_size = skb_shinfo(skb)->gso_size;
		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
			hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
		else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
			hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
		else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
			hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
		else
			BUG();
		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
			hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
	} else {
		hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
		hdr->gso_size = hdr->hdr_len = 0;
	}

	vnet_hdr_to_sg(sg, skb);
	num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
	__skb_queue_head(&vi->send, skb);

again:
	/* Free up any pending old buffers before queueing new ones. */
	free_old_xmit_skbs(vi);
	err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
	if (err) {
		pr_debug("%s: virtio not prepared to send\n", dev->name);
		netif_stop_queue(dev);

		/* Activate callback for using skbs: if this returns false it
		 * means some were used in the meantime. */
		if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
			vi->svq->vq_ops->disable_cb(vi->svq);
			netif_start_queue(dev);
			goto again;
		}
		__skb_unlink(skb, &vi->send);

		return NETDEV_TX_BUSY;
	}
	vi->svq->vq_ops->kick(vi->svq);

	return 0;
}

#ifdef CONFIG_NET_POLL_CONTROLLER
static void virtnet_netpoll(struct net_device *dev)
{
	struct virtnet_info *vi = netdev_priv(dev);

	napi_schedule(&vi->napi);
}
#endif

static int virtnet_open(struct net_device *dev)
{
	struct virtnet_info *vi = netdev_priv(dev);

	napi_enable(&vi->napi);

	/* If all buffers were filled by other side before we napi_enabled, we
	 * won't get another interrupt, so process any outstanding packets
	 * now.  virtnet_poll wants re-enable the queue, so we disable here.
	 * We synchronize against interrupts via NAPI_STATE_SCHED */
	if (netif_rx_schedule_prep(dev, &vi->napi)) {
		vi->rvq->vq_ops->disable_cb(vi->rvq);
		__netif_rx_schedule(dev, &vi->napi);
	}
	return 0;
}

static int virtnet_close(struct net_device *dev)
{
	struct virtnet_info *vi = netdev_priv(dev);

	napi_disable(&vi->napi);

	return 0;
}

static int virtnet_probe(struct virtio_device *vdev)
{
	int err;
	struct net_device *dev;
	struct virtnet_info *vi;

	/* Allocate ourselves a network device with room for our info */
	dev = alloc_etherdev(sizeof(struct virtnet_info));
	if (!dev)
		return -ENOMEM;

	/* Set up network device as normal. */
	dev->open = virtnet_open;
	dev->stop = virtnet_close;
	dev->hard_start_xmit = start_xmit;
	dev->features = NETIF_F_HIGHDMA;
#ifdef CONFIG_NET_POLL_CONTROLLER
	dev->poll_controller = virtnet_netpoll;
#endif
	SET_NETDEV_DEV(dev, &vdev->dev);

	/* Do we support "hardware" checksums? */
	if (csum && vdev->config->feature(vdev, VIRTIO_NET_F_CSUM)) {
		/* This opens up the world of extra features. */
		dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
		if (gso && vdev->config->feature(vdev, VIRTIO_NET_F_GSO)) {
			dev->features |= NETIF_F_TSO | NETIF_F_UFO
				| NETIF_F_TSO_ECN | NETIF_F_TSO6;
		}
	}

	/* Configuration may specify what MAC to use.  Otherwise random. */
	if (vdev->config->feature(vdev, VIRTIO_NET_F_MAC)) {
		vdev->config->get(vdev,
				  offsetof(struct virtio_net_config, mac),
				  dev->dev_addr, dev->addr_len);
	} else
		random_ether_addr(dev->dev_addr);

	/* Set up our device-specific information */
	vi = netdev_priv(dev);
	netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
	vi->dev = dev;
	vi->vdev = vdev;
	vdev->priv = vi;

	/* We expect two virtqueues, receive then send. */
	vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done);
	if (IS_ERR(vi->rvq)) {
		err = PTR_ERR(vi->rvq);
		goto free;
	}

	vi->svq = vdev->config->find_vq(vdev, 1, skb_xmit_done);
	if (IS_ERR(vi->svq)) {
		err = PTR_ERR(vi->svq);
		goto free_recv;
	}

	/* Initialize our empty receive and send queues. */
	skb_queue_head_init(&vi->recv);
	skb_queue_head_init(&vi->send);

	err = register_netdev(dev);
	if (err) {
		pr_debug("virtio_net: registering device failed\n");
		goto free_send;
	}

	/* Last of all, set up some receive buffers. */
	try_fill_recv(vi);

	/* If we didn't even get one input buffer, we're useless. */
	if (vi->num == 0) {
		err = -ENOMEM;
		goto unregister;
	}

	pr_debug("virtnet: registered device %s\n", dev->name);
	return 0;

unregister:
	unregister_netdev(dev);
free_send:
	vdev->config->del_vq(vi->svq);
free_recv:
	vdev->config->del_vq(vi->rvq);
free:
	free_netdev(dev);
	return err;
}

static void virtnet_remove(struct virtio_device *vdev)
{
	struct virtnet_info *vi = vdev->priv;
	struct sk_buff *skb;

	/* Stop all the virtqueues. */
	vdev->config->reset(vdev);

	/* Free our skbs in send and recv queues, if any. */
	while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
		kfree_skb(skb);
		vi->num--;
	}
	while ((skb = __skb_dequeue(&vi->send)) != NULL)
		kfree_skb(skb);

	BUG_ON(vi->num != 0);

	vdev->config->del_vq(vi->svq);
	vdev->config->del_vq(vi->rvq);
	unregister_netdev(vi->dev);
	free_netdev(vi->dev);
}

static struct virtio_device_id id_table[] = {
	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
	{ 0 },
};

static struct virtio_driver virtio_net = {
	.driver.name =	KBUILD_MODNAME,
	.driver.owner =	THIS_MODULE,
	.id_table =	id_table,
	.probe =	virtnet_probe,
	.remove =	__devexit_p(virtnet_remove),
};

static int __init init(void)
{
	return register_virtio_driver(&virtio_net);
}

static void __exit fini(void)
{
	unregister_virtio_driver(&virtio_net);
}
module_init(init);
module_exit(fini);

MODULE_DEVICE_TABLE(virtio, id_table);
MODULE_DESCRIPTION("Virtio network driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
296f96fc RR	1	/* A simple network driver using virtio.
	2	*
	3	* Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License as published by
	7	* the Free Software Foundation; either version 2 of the License, or
	8	* (at your option) any later version.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, write to the Free Software
	17	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	18	*/
	19	//#define DEBUG
	20	#include <linux/netdevice.h>
	21	#include <linux/etherdevice.h>
	22	#include <linux/module.h>
	23	#include <linux/virtio.h>
	24	#include <linux/virtio_net.h>
	25	#include <linux/scatterlist.h>
	26
6c0cd7c0 DL	27	static int napi_weight = 128;
	28	module_param(napi_weight, int, 0444);
	29
34a48579 RR	30	static int csum = 1, gso = 1;
	31	module_param(csum, bool, 0444);
	32	module_param(gso, bool, 0444);
	33
296f96fc RR	34	/* FIXME: MTU in config. */
	35	#define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN)
	36
	37	struct virtnet_info
	38	{
	39	struct virtio_device *vdev;
	40	struct virtqueue rvq, svq;
	41	struct net_device *dev;
	42	struct napi_struct napi;
	43
	44	/* Number of input buffers, and max we've ever had. */
	45	unsigned int num, max;
	46
	47	/* Receive & send queues. */
	48	struct sk_buff_head recv;
	49	struct sk_buff_head send;
	50	};
	51
	52	static inline struct virtio_net_hdr skb_vnet_hdr(struct sk_buff skb)
	53	{
	54	return (struct virtio_net_hdr *)skb->cb;
	55	}
	56
	57	static inline void vnet_hdr_to_sg(struct scatterlist sg, struct sk_buff skb)
	58	{
	59	sg_init_one(sg, skb_vnet_hdr(skb), sizeof(struct virtio_net_hdr));
	60	}
	61
2cb9c6ba	62	static void skb_xmit_done(struct virtqueue *svq)
296f96fc	63	{
2cb9c6ba	64	struct virtnet_info *vi = svq->vdev->priv;
296f96fc	65
2cb9c6ba RR	66	/* Suppress further interrupts. */
	67	svq->vq_ops->disable_cb(svq);
	68	/* We were waiting for more output buffers. */
296f96fc	69	netif_wake_queue(vi->dev);
296f96fc RR	70	}
	71
	72	static void receive_skb(struct net_device dev, struct sk_buff skb,
	73	unsigned len)
	74	{
	75	struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);
	76
	77	if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
	78	pr_debug("%s: short packet %i\n", dev->name, len);
	79	dev->stats.rx_length_errors++;
	80	goto drop;
	81	}
	82	len -= sizeof(struct virtio_net_hdr);
	83	BUG_ON(len > MAX_PACKET_LEN);
	84
	85	skb_trim(skb, len);
	86	skb->protocol = eth_type_trans(skb, dev);
	87	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
	88	ntohs(skb->protocol), skb->len, skb->pkt_type);
	89	dev->stats.rx_bytes += skb->len;
	90	dev->stats.rx_packets++;
	91
	92	if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
	93	pr_debug("Needs csum!\n");
f35d9d8a	94	if (!skb_partial_csum_set(skb,hdr->csum_start,hdr->csum_offset))
296f96fc	95	goto frame_err;
296f96fc RR	96	}
	97
	98	if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
	99	pr_debug("GSO!\n");
34a48579	100	switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
296f96fc RR	101	case VIRTIO_NET_HDR_GSO_TCPV4:
	102	skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
	103	break;
296f96fc RR	104	case VIRTIO_NET_HDR_GSO_UDP:
	105	skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
	106	break;
	107	case VIRTIO_NET_HDR_GSO_TCPV6:
	108	skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
	109	break;
	110	default:
	111	if (net_ratelimit())
	112	printk(KERN_WARNING "%s: bad gso type %u.\n",
	113	dev->name, hdr->gso_type);
	114	goto frame_err;
	115	}
	116
34a48579 RR	117	if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
	118	skb_shinfo(skb)->gso_type \|= SKB_GSO_TCP_ECN;
	119
296f96fc RR	120	skb_shinfo(skb)->gso_size = hdr->gso_size;
	121	if (skb_shinfo(skb)->gso_size == 0) {
	122	if (net_ratelimit())
	123	printk(KERN_WARNING "%s: zero gso size.\n",
	124	dev->name);
	125	goto frame_err;
	126	}
	127
	128	/* Header must be checked, and gso_segs computed. */
	129	skb_shinfo(skb)->gso_type \|= SKB_GSO_DODGY;
	130	skb_shinfo(skb)->gso_segs = 0;
	131	}
	132
	133	netif_receive_skb(skb);
	134	return;
	135
	136	frame_err:
	137	dev->stats.rx_frame_errors++;
	138	drop:
	139	dev_kfree_skb(skb);
	140	}
	141
	142	static void try_fill_recv(struct virtnet_info *vi)
	143	{
	144	struct sk_buff *skb;
	145	struct scatterlist sg[1+MAX_SKB_FRAGS];
	146	int num, err;
	147
4d125de3	148	sg_init_table(sg, 1+MAX_SKB_FRAGS);
296f96fc RR	149	for (;;) {
	150	skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
	151	if (unlikely(!skb))
	152	break;
	153
	154	skb_put(skb, MAX_PACKET_LEN);
	155	vnet_hdr_to_sg(sg, skb);
	156	num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
	157	skb_queue_head(&vi->recv, skb);
	158
	159	err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
	160	if (err) {
	161	skb_unlink(skb, &vi->recv);
	162	kfree_skb(skb);
	163	break;
	164	}
	165	vi->num++;
	166	}
	167	if (unlikely(vi->num > vi->max))
	168	vi->max = vi->num;
	169	vi->rvq->vq_ops->kick(vi->rvq);
	170	}
	171
18445c4d	172	static void skb_recv_done(struct virtqueue *rvq)
296f96fc RR	173	{
296f96fc RR	174	struct virtnet_info *vi = rvq->vdev->priv;
18445c4d RR	175	/* Schedule NAPI, Suppress further interrupts if successful. */
	176	if (netif_rx_schedule_prep(vi->dev, &vi->napi)) {
	177	rvq->vq_ops->disable_cb(rvq);
	178	__netif_rx_schedule(vi->dev, &vi->napi);
	179	}
296f96fc RR	180	}
	181
	182	static int virtnet_poll(struct napi_struct *napi, int budget)
	183	{
	184	struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
	185	struct sk_buff *skb = NULL;
	186	unsigned int len, received = 0;
	187
	188	again:
	189	while (received < budget &&
	190	(skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
	191	__skb_unlink(skb, &vi->recv);
	192	receive_skb(vi->dev, skb, len);
	193	vi->num--;
	194	received++;
	195	}
	196
	197	/* FIXME: If we oom and completely run out of inbufs, we need
	198	* to start a timer trying to fill more. */
	199	if (vi->num < vi->max / 2)
	200	try_fill_recv(vi);
	201
8329d98e RR	202	/* Out of packets? */
8329d98e RR	203	if (received < budget) {
296f96fc	204	netif_rx_complete(vi->dev, napi);
18445c4d	205	if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq))
4265f161 CB	206	&& napi_schedule_prep(napi)) {
	207	vi->rvq->vq_ops->disable_cb(vi->rvq);
	208	__netif_rx_schedule(vi->dev, napi);
296f96fc	209	goto again;
4265f161	210	}
296f96fc RR	211	}
	212
	213	return received;
	214	}
	215
	216	static void free_old_xmit_skbs(struct virtnet_info *vi)
	217	{
	218	struct sk_buff *skb;
	219	unsigned int len;
	220
	221	while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
	222	pr_debug("Sent skb %p\n", skb);
	223	__skb_unlink(skb, &vi->send);
655aa31f	224	vi->dev->stats.tx_bytes += skb->len;
296f96fc RR	225	vi->dev->stats.tx_packets++;
	226	kfree_skb(skb);
	227	}
	228	}
	229
	230	static int start_xmit(struct sk_buff skb, struct net_device dev)
	231	{
	232	struct virtnet_info *vi = netdev_priv(dev);
	233	int num, err;
	234	struct scatterlist sg[1+MAX_SKB_FRAGS];
	235	struct virtio_net_hdr *hdr;
	236	const unsigned char dest = ((struct ethhdr )skb->data)->h_dest;
296f96fc	237
4d125de3 RR	238	sg_init_table(sg, 1+MAX_SKB_FRAGS);
4d125de3 RR	239
21f644f3 DM	240	pr_debug("%s: xmit %p " MAC_FMT "\n", dev->name, skb,
	241	dest[0], dest[1], dest[2],
	242	dest[3], dest[4], dest[5]);
296f96fc	243
296f96fc RR	244	/* Encode metadata header at front. */
	245	hdr = skb_vnet_hdr(skb);
	246	if (skb->ip_summed == CHECKSUM_PARTIAL) {
	247	hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
	248	hdr->csum_start = skb->csum_start - skb_headroom(skb);
	249	hdr->csum_offset = skb->csum_offset;
	250	} else {
	251	hdr->flags = 0;
	252	hdr->csum_offset = hdr->csum_start = 0;
	253	}
	254
	255	if (skb_is_gso(skb)) {
50c8ea80	256	hdr->hdr_len = skb_transport_header(skb) - skb->data;
296f96fc	257	hdr->gso_size = skb_shinfo(skb)->gso_size;
34a48579	258	if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
296f96fc RR	259	hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
	260	else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
	261	hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
	262	else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
	263	hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
	264	else
	265	BUG();
34a48579 RR	266	if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
34a48579 RR	267	hdr->gso_type \|= VIRTIO_NET_HDR_GSO_ECN;
296f96fc RR	268	} else {
296f96fc RR	269	hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
50c8ea80	270	hdr->gso_size = hdr->hdr_len = 0;
296f96fc RR	271	}
	272
	273	vnet_hdr_to_sg(sg, skb);
	274	num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
	275	__skb_queue_head(&vi->send, skb);
2cb9c6ba RR	276
	277	again:
	278	/* Free up any pending old buffers before queueing new ones. */
	279	free_old_xmit_skbs(vi);
296f96fc RR	280	err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
	281	if (err) {
	282	pr_debug("%s: virtio not prepared to send\n", dev->name);
296f96fc	283	netif_stop_queue(dev);
2cb9c6ba	284
4265f161	285	/* Activate callback for using skbs: if this returns false it
2cb9c6ba RR	286	* means some were used in the meantime. */
2cb9c6ba RR	287	if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
4265f161	288	vi->svq->vq_ops->disable_cb(vi->svq);
2cb9c6ba RR	289	netif_start_queue(dev);
	290	goto again;
	291	}
	292	__skb_unlink(skb, &vi->send);
	293
296f96fc RR	294	return NETDEV_TX_BUSY;
	295	}
	296	vi->svq->vq_ops->kick(vi->svq);
	297
	298	return 0;
	299	}
	300
da74e89d AS	301	#ifdef CONFIG_NET_POLL_CONTROLLER
	302	static void virtnet_netpoll(struct net_device *dev)
	303	{
	304	struct virtnet_info *vi = netdev_priv(dev);
	305
	306	napi_schedule(&vi->napi);
	307	}
	308	#endif
	309
296f96fc RR	310	static int virtnet_open(struct net_device *dev)
	311	{
	312	struct virtnet_info *vi = netdev_priv(dev);
	313
296f96fc	314	napi_enable(&vi->napi);
a48bd8f6 RR	315
	316	/* If all buffers were filled by other side before we napi_enabled, we
	317	* won't get another interrupt, so process any outstanding packets
370076d9 CB	318	* now. virtnet_poll wants re-enable the queue, so we disable here.
	319	* We synchronize against interrupts via NAPI_STATE_SCHED */
	320	if (netif_rx_schedule_prep(dev, &vi->napi)) {
	321	vi->rvq->vq_ops->disable_cb(vi->rvq);
	322	__netif_rx_schedule(dev, &vi->napi);
	323	}
296f96fc RR	324	return 0;
	325	}
	326
	327	static int virtnet_close(struct net_device *dev)
	328	{
	329	struct virtnet_info *vi = netdev_priv(dev);
296f96fc RR	330
	331	napi_disable(&vi->napi);
	332
296f96fc RR	333	return 0;
	334	}
	335
	336	static int virtnet_probe(struct virtio_device *vdev)
	337	{
	338	int err;
296f96fc RR	339	struct net_device *dev;
296f96fc RR	340	struct virtnet_info *vi;
296f96fc RR	341
	342	/* Allocate ourselves a network device with room for our info */
	343	dev = alloc_etherdev(sizeof(struct virtnet_info));
	344	if (!dev)
	345	return -ENOMEM;
	346
	347	/* Set up network device as normal. */
296f96fc RR	348	dev->open = virtnet_open;
	349	dev->stop = virtnet_close;
	350	dev->hard_start_xmit = start_xmit;
	351	dev->features = NETIF_F_HIGHDMA;
da74e89d AS	352	#ifdef CONFIG_NET_POLL_CONTROLLER
	353	dev->poll_controller = virtnet_netpoll;
	354	#endif
296f96fc RR	355	SET_NETDEV_DEV(dev, &vdev->dev);
	356
	357	/* Do we support "hardware" checksums? */
34a48579	358	if (csum && vdev->config->feature(vdev, VIRTIO_NET_F_CSUM)) {
296f96fc RR	359	/* This opens up the world of extra features. */
296f96fc RR	360	dev->features \|= NETIF_F_HW_CSUM\|NETIF_F_SG\|NETIF_F_FRAGLIST;
34a48579 RR	361	if (gso && vdev->config->feature(vdev, VIRTIO_NET_F_GSO)) {
	362	dev->features \|= NETIF_F_TSO \| NETIF_F_UFO
	363	\| NETIF_F_TSO_ECN \| NETIF_F_TSO6;
	364	}
296f96fc RR	365	}
	366
	367	/* Configuration may specify what MAC to use. Otherwise random. */
a586d4f6 RR	368	if (vdev->config->feature(vdev, VIRTIO_NET_F_MAC)) {
	369	vdev->config->get(vdev,
	370	offsetof(struct virtio_net_config, mac),
	371	dev->dev_addr, dev->addr_len);
296f96fc RR	372	} else
	373	random_ether_addr(dev->dev_addr);
	374
	375	/* Set up our device-specific information */
	376	vi = netdev_priv(dev);
6c0cd7c0	377	netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
296f96fc RR	378	vi->dev = dev;
296f96fc RR	379	vi->vdev = vdev;
d9d5dcc8	380	vdev->priv = vi;
296f96fc RR	381
296f96fc RR	382	/* We expect two virtqueues, receive then send. */
a586d4f6	383	vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done);
296f96fc RR	384	if (IS_ERR(vi->rvq)) {
	385	err = PTR_ERR(vi->rvq);
	386	goto free;
	387	}
	388
a586d4f6	389	vi->svq = vdev->config->find_vq(vdev, 1, skb_xmit_done);
296f96fc RR	390	if (IS_ERR(vi->svq)) {
	391	err = PTR_ERR(vi->svq);
	392	goto free_recv;
	393	}
	394
	395	/* Initialize our empty receive and send queues. */
	396	skb_queue_head_init(&vi->recv);
	397	skb_queue_head_init(&vi->send);
	398
	399	err = register_netdev(dev);
	400	if (err) {
	401	pr_debug("virtio_net: registering device failed\n");
	402	goto free_send;
	403	}
b3369c1f RR	404
	405	/* Last of all, set up some receive buffers. */
	406	try_fill_recv(vi);
	407
	408	/* If we didn't even get one input buffer, we're useless. */
	409	if (vi->num == 0) {
	410	err = -ENOMEM;
	411	goto unregister;
	412	}
	413
296f96fc	414	pr_debug("virtnet: registered device %s\n", dev->name);
296f96fc RR	415	return 0;
296f96fc RR	416
b3369c1f RR	417	unregister:
b3369c1f RR	418	unregister_netdev(dev);
296f96fc RR	419	free_send:
	420	vdev->config->del_vq(vi->svq);
	421	free_recv:
	422	vdev->config->del_vq(vi->rvq);
	423	free:
	424	free_netdev(dev);
	425	return err;
	426	}
	427
	428	static void virtnet_remove(struct virtio_device *vdev)
	429	{
74b2553f	430	struct virtnet_info *vi = vdev->priv;
b3369c1f RR	431	struct sk_buff *skb;
b3369c1f RR	432
6e5aa7ef RR	433	/* Stop all the virtqueues. */
	434	vdev->config->reset(vdev);
	435
b3369c1f	436	/* Free our skbs in send and recv queues, if any. */
b3369c1f RR	437	while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
	438	kfree_skb(skb);
	439	vi->num--;
	440	}
b3369c1f RR	441	while ((skb = __skb_dequeue(&vi->send)) != NULL)
	442	kfree_skb(skb);
	443
	444	BUG_ON(vi->num != 0);
74b2553f RR	445
	446	vdev->config->del_vq(vi->svq);
	447	vdev->config->del_vq(vi->rvq);
	448	unregister_netdev(vi->dev);
	449	free_netdev(vi->dev);
296f96fc RR	450	}
	451
	452	static struct virtio_device_id id_table[] = {
	453	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
	454	{ 0 },
	455	};
	456
	457	static struct virtio_driver virtio_net = {
	458	.driver.name = KBUILD_MODNAME,
	459	.driver.owner = THIS_MODULE,
	460	.id_table = id_table,
	461	.probe = virtnet_probe,
	462	.remove = __devexit_p(virtnet_remove),
	463	};
	464
	465	static int __init init(void)
	466	{
	467	return register_virtio_driver(&virtio_net);
	468	}
	469
	470	static void __exit fini(void)
	471	{
	472	unregister_virtio_driver(&virtio_net);
	473	}
	474	module_init(init);
	475	module_exit(fini);
	476
	477	MODULE_DEVICE_TABLE(virtio, id_table);
	478	MODULE_DESCRIPTION("Virtio network driver");
	479	MODULE_LICENSE("GPL");