[linux.git] / net / vmw_vsock / virtio_transport.c

/*
 * virtio transport for vsock
 *
 * Copyright (C) 2013-2015 Red Hat, Inc.
 * Author: Asias He <[email protected]>
 *         Stefan Hajnoczi <[email protected]>
 *
 * Some of the code is take from Gerd Hoffmann <[email protected]>'s
 * early virtio-vsock proof-of-concept bits.
 *
 * This work is licensed under the terms of the GNU GPL, version 2.
 */
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/atomic.h>
#include <linux/virtio.h>
#include <linux/virtio_ids.h>
#include <linux/virtio_config.h>
#include <linux/virtio_vsock.h>
#include <net/sock.h>
#include <linux/mutex.h>
#include <net/af_vsock.h>

static struct workqueue_struct *virtio_vsock_workqueue;
static struct virtio_vsock *the_virtio_vsock;
static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */

struct virtio_vsock {
	struct virtio_device *vdev;
	struct virtqueue *vqs[VSOCK_VQ_MAX];

	/* Virtqueue processing is deferred to a workqueue */
	struct work_struct tx_work;
	struct work_struct rx_work;
	struct work_struct event_work;

	/* The following fields are protected by tx_lock.  vqs[VSOCK_VQ_TX]
	 * must be accessed with tx_lock held.
	 */
	struct mutex tx_lock;

	struct work_struct send_pkt_work;
	spinlock_t send_pkt_list_lock;
	struct list_head send_pkt_list;

	struct work_struct loopback_work;
	spinlock_t loopback_list_lock; /* protects loopback_list */
	struct list_head loopback_list;

	atomic_t queued_replies;

	/* The following fields are protected by rx_lock.  vqs[VSOCK_VQ_RX]
	 * must be accessed with rx_lock held.
	 */
	struct mutex rx_lock;
	int rx_buf_nr;
	int rx_buf_max_nr;

	/* The following fields are protected by event_lock.
	 * vqs[VSOCK_VQ_EVENT] must be accessed with event_lock held.
	 */
	struct mutex event_lock;
	struct virtio_vsock_event event_list[8];

	u32 guest_cid;
};

static struct virtio_vsock *virtio_vsock_get(void)
{
	return the_virtio_vsock;
}

static u32 virtio_transport_get_local_cid(void)
{
	struct virtio_vsock *vsock = virtio_vsock_get();

	return vsock->guest_cid;
}

static void virtio_transport_loopback_work(struct work_struct *work)
{
	struct virtio_vsock *vsock =
		container_of(work, struct virtio_vsock, loopback_work);
	LIST_HEAD(pkts);

	spin_lock_bh(&vsock->loopback_list_lock);
	list_splice_init(&vsock->loopback_list, &pkts);
	spin_unlock_bh(&vsock->loopback_list_lock);

	mutex_lock(&vsock->rx_lock);
	while (!list_empty(&pkts)) {
		struct virtio_vsock_pkt *pkt;

		pkt = list_first_entry(&pkts, struct virtio_vsock_pkt, list);
		list_del_init(&pkt->list);

		virtio_transport_recv_pkt(pkt);
	}
	mutex_unlock(&vsock->rx_lock);
}

static int virtio_transport_send_pkt_loopback(struct virtio_vsock *vsock,
					      struct virtio_vsock_pkt *pkt)
{
	int len = pkt->len;

	spin_lock_bh(&vsock->loopback_list_lock);
	list_add_tail(&pkt->list, &vsock->loopback_list);
	spin_unlock_bh(&vsock->loopback_list_lock);

	queue_work(virtio_vsock_workqueue, &vsock->loopback_work);

	return len;
}

static void
virtio_transport_send_pkt_work(struct work_struct *work)
{
	struct virtio_vsock *vsock =
		container_of(work, struct virtio_vsock, send_pkt_work);
	struct virtqueue *vq;
	bool added = false;
	bool restart_rx = false;

	mutex_lock(&vsock->tx_lock);

	vq = vsock->vqs[VSOCK_VQ_TX];

	for (;;) {
		struct virtio_vsock_pkt *pkt;
		struct scatterlist hdr, buf, *sgs[2];
		int ret, in_sg = 0, out_sg = 0;
		bool reply;

		spin_lock_bh(&vsock->send_pkt_list_lock);
		if (list_empty(&vsock->send_pkt_list)) {
			spin_unlock_bh(&vsock->send_pkt_list_lock);
			break;
		}

		pkt = list_first_entry(&vsock->send_pkt_list,
				       struct virtio_vsock_pkt, list);
		list_del_init(&pkt->list);
		spin_unlock_bh(&vsock->send_pkt_list_lock);

		virtio_transport_deliver_tap_pkt(pkt);

		reply = pkt->reply;

		sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
		sgs[out_sg++] = &hdr;
		if (pkt->buf) {
			sg_init_one(&buf, pkt->buf, pkt->len);
			sgs[out_sg++] = &buf;
		}

		ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, pkt, GFP_KERNEL);
		/* Usually this means that there is no more space available in
		 * the vq
		 */
		if (ret < 0) {
			spin_lock_bh(&vsock->send_pkt_list_lock);
			list_add(&pkt->list, &vsock->send_pkt_list);
			spin_unlock_bh(&vsock->send_pkt_list_lock);
			break;
		}

		if (reply) {
			struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
			int val;

			val = atomic_dec_return(&vsock->queued_replies);

			/* Do we now have resources to resume rx processing? */
			if (val + 1 == virtqueue_get_vring_size(rx_vq))
				restart_rx = true;
		}

		added = true;
	}

	if (added)
		virtqueue_kick(vq);

	mutex_unlock(&vsock->tx_lock);

	if (restart_rx)
		queue_work(virtio_vsock_workqueue, &vsock->rx_work);
}

static int
virtio_transport_send_pkt(struct virtio_vsock_pkt *pkt)
{
	struct virtio_vsock *vsock;
	int len = pkt->len;

	vsock = virtio_vsock_get();
	if (!vsock) {
		virtio_transport_free_pkt(pkt);
		return -ENODEV;
	}

	if (le32_to_cpu(pkt->hdr.dst_cid) == vsock->guest_cid)
		return virtio_transport_send_pkt_loopback(vsock, pkt);

	if (pkt->reply)
		atomic_inc(&vsock->queued_replies);

	spin_lock_bh(&vsock->send_pkt_list_lock);
	list_add_tail(&pkt->list, &vsock->send_pkt_list);
	spin_unlock_bh(&vsock->send_pkt_list_lock);

	queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
	return len;
}

static int
virtio_transport_cancel_pkt(struct vsock_sock *vsk)
{
	struct virtio_vsock *vsock;
	struct virtio_vsock_pkt *pkt, *n;
	int cnt = 0;
	LIST_HEAD(freeme);

	vsock = virtio_vsock_get();
	if (!vsock) {
		return -ENODEV;
	}

	spin_lock_bh(&vsock->send_pkt_list_lock);
	list_for_each_entry_safe(pkt, n, &vsock->send_pkt_list, list) {
		if (pkt->vsk != vsk)
			continue;
		list_move(&pkt->list, &freeme);
	}
	spin_unlock_bh(&vsock->send_pkt_list_lock);

	list_for_each_entry_safe(pkt, n, &freeme, list) {
		if (pkt->reply)
			cnt++;
		list_del(&pkt->list);
		virtio_transport_free_pkt(pkt);
	}

	if (cnt) {
		struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
		int new_cnt;

		new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);
		if (new_cnt + cnt >= virtqueue_get_vring_size(rx_vq) &&
		    new_cnt < virtqueue_get_vring_size(rx_vq))
			queue_work(virtio_vsock_workqueue, &vsock->rx_work);
	}

	return 0;
}

static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
{
	int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
	struct virtio_vsock_pkt *pkt;
	struct scatterlist hdr, buf, *sgs[2];
	struct virtqueue *vq;
	int ret;

	vq = vsock->vqs[VSOCK_VQ_RX];

	do {
		pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
		if (!pkt)
			break;

		pkt->buf = kmalloc(buf_len, GFP_KERNEL);
		if (!pkt->buf) {
			virtio_transport_free_pkt(pkt);
			break;
		}

		pkt->len = buf_len;

		sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
		sgs[0] = &hdr;

		sg_init_one(&buf, pkt->buf, buf_len);
		sgs[1] = &buf;
		ret = virtqueue_add_sgs(vq, sgs, 0, 2, pkt, GFP_KERNEL);
		if (ret) {
			virtio_transport_free_pkt(pkt);
			break;
		}
		vsock->rx_buf_nr++;
	} while (vq->num_free);
	if (vsock->rx_buf_nr > vsock->rx_buf_max_nr)
		vsock->rx_buf_max_nr = vsock->rx_buf_nr;
	virtqueue_kick(vq);
}

static void virtio_transport_tx_work(struct work_struct *work)
{
	struct virtio_vsock *vsock =
		container_of(work, struct virtio_vsock, tx_work);
	struct virtqueue *vq;
	bool added = false;

	vq = vsock->vqs[VSOCK_VQ_TX];
	mutex_lock(&vsock->tx_lock);
	do {
		struct virtio_vsock_pkt *pkt;
		unsigned int len;

		virtqueue_disable_cb(vq);
		while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
			virtio_transport_free_pkt(pkt);
			added = true;
		}
	} while (!virtqueue_enable_cb(vq));
	mutex_unlock(&vsock->tx_lock);

	if (added)
		queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
}

/* Is there space left for replies to rx packets? */
static bool virtio_transport_more_replies(struct virtio_vsock *vsock)
{
	struct virtqueue *vq = vsock->vqs[VSOCK_VQ_RX];
	int val;

	smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
	val = atomic_read(&vsock->queued_replies);

	return val < virtqueue_get_vring_size(vq);
}

static void virtio_transport_rx_work(struct work_struct *work)
{
	struct virtio_vsock *vsock =
		container_of(work, struct virtio_vsock, rx_work);
	struct virtqueue *vq;

	vq = vsock->vqs[VSOCK_VQ_RX];

	mutex_lock(&vsock->rx_lock);

	do {
		virtqueue_disable_cb(vq);
		for (;;) {
			struct virtio_vsock_pkt *pkt;
			unsigned int len;

			if (!virtio_transport_more_replies(vsock)) {
				/* Stop rx until the device processes already
				 * pending replies.  Leave rx virtqueue
				 * callbacks disabled.
				 */
				goto out;
			}

			pkt = virtqueue_get_buf(vq, &len);
			if (!pkt) {
				break;
			}

			vsock->rx_buf_nr--;

			/* Drop short/long packets */
			if (unlikely(len < sizeof(pkt->hdr) ||
				     len > sizeof(pkt->hdr) + pkt->len)) {
				virtio_transport_free_pkt(pkt);
				continue;
			}

			pkt->len = len - sizeof(pkt->hdr);
			virtio_transport_deliver_tap_pkt(pkt);
			virtio_transport_recv_pkt(pkt);
		}
	} while (!virtqueue_enable_cb(vq));

out:
	if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
		virtio_vsock_rx_fill(vsock);
	mutex_unlock(&vsock->rx_lock);
}

/* event_lock must be held */
static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock,
				       struct virtio_vsock_event *event)
{
	struct scatterlist sg;
	struct virtqueue *vq;

	vq = vsock->vqs[VSOCK_VQ_EVENT];

	sg_init_one(&sg, event, sizeof(*event));

	return virtqueue_add_inbuf(vq, &sg, 1, event, GFP_KERNEL);
}

/* event_lock must be held */
static void virtio_vsock_event_fill(struct virtio_vsock *vsock)
{
	size_t i;

	for (i = 0; i < ARRAY_SIZE(vsock->event_list); i++) {
		struct virtio_vsock_event *event = &vsock->event_list[i];

		virtio_vsock_event_fill_one(vsock, event);
	}

	virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
}

static void virtio_vsock_reset_sock(struct sock *sk)
{
	lock_sock(sk);
	sk->sk_state = SS_UNCONNECTED;
	sk->sk_err = ECONNRESET;
	sk->sk_error_report(sk);
	release_sock(sk);
}

static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock)
{
	struct virtio_device *vdev = vsock->vdev;
	__le64 guest_cid;

	vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),
			  &guest_cid, sizeof(guest_cid));
	vsock->guest_cid = le64_to_cpu(guest_cid);
}

/* event_lock must be held */
static void virtio_vsock_event_handle(struct virtio_vsock *vsock,
				      struct virtio_vsock_event *event)
{
	switch (le32_to_cpu(event->id)) {
	case VIRTIO_VSOCK_EVENT_TRANSPORT_RESET:
		virtio_vsock_update_guest_cid(vsock);
		vsock_for_each_connected_socket(virtio_vsock_reset_sock);
		break;
	}
}

static void virtio_transport_event_work(struct work_struct *work)
{
	struct virtio_vsock *vsock =
		container_of(work, struct virtio_vsock, event_work);
	struct virtqueue *vq;

	vq = vsock->vqs[VSOCK_VQ_EVENT];

	mutex_lock(&vsock->event_lock);

	do {
		struct virtio_vsock_event *event;
		unsigned int len;

		virtqueue_disable_cb(vq);
		while ((event = virtqueue_get_buf(vq, &len)) != NULL) {
			if (len == sizeof(*event))
				virtio_vsock_event_handle(vsock, event);

			virtio_vsock_event_fill_one(vsock, event);
		}
	} while (!virtqueue_enable_cb(vq));

	virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);

	mutex_unlock(&vsock->event_lock);
}

static void virtio_vsock_event_done(struct virtqueue *vq)
{
	struct virtio_vsock *vsock = vq->vdev->priv;

	if (!vsock)
		return;
	queue_work(virtio_vsock_workqueue, &vsock->event_work);
}

static void virtio_vsock_tx_done(struct virtqueue *vq)
{
	struct virtio_vsock *vsock = vq->vdev->priv;

	if (!vsock)
		return;
	queue_work(virtio_vsock_workqueue, &vsock->tx_work);
}

static void virtio_vsock_rx_done(struct virtqueue *vq)
{
	struct virtio_vsock *vsock = vq->vdev->priv;

	if (!vsock)
		return;
	queue_work(virtio_vsock_workqueue, &vsock->rx_work);
}

static struct virtio_transport virtio_transport = {
	.transport = {
		.get_local_cid            = virtio_transport_get_local_cid,

		.init                     = virtio_transport_do_socket_init,
		.destruct                 = virtio_transport_destruct,
		.release                  = virtio_transport_release,
		.connect                  = virtio_transport_connect,
		.shutdown                 = virtio_transport_shutdown,
		.cancel_pkt               = virtio_transport_cancel_pkt,

		.dgram_bind               = virtio_transport_dgram_bind,
		.dgram_dequeue            = virtio_transport_dgram_dequeue,
		.dgram_enqueue            = virtio_transport_dgram_enqueue,
		.dgram_allow              = virtio_transport_dgram_allow,

		.stream_dequeue           = virtio_transport_stream_dequeue,
		.stream_enqueue           = virtio_transport_stream_enqueue,
		.stream_has_data          = virtio_transport_stream_has_data,
		.stream_has_space         = virtio_transport_stream_has_space,
		.stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
		.stream_is_active         = virtio_transport_stream_is_active,
		.stream_allow             = virtio_transport_stream_allow,

		.notify_poll_in           = virtio_transport_notify_poll_in,
		.notify_poll_out          = virtio_transport_notify_poll_out,
		.notify_recv_init         = virtio_transport_notify_recv_init,
		.notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
		.notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
		.notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
		.notify_send_init         = virtio_transport_notify_send_init,
		.notify_send_pre_block    = virtio_transport_notify_send_pre_block,
		.notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,

		.set_buffer_size          = virtio_transport_set_buffer_size,
		.set_min_buffer_size      = virtio_transport_set_min_buffer_size,
		.set_max_buffer_size      = virtio_transport_set_max_buffer_size,
		.get_buffer_size          = virtio_transport_get_buffer_size,
		.get_min_buffer_size      = virtio_transport_get_min_buffer_size,
		.get_max_buffer_size      = virtio_transport_get_max_buffer_size,
	},

	.send_pkt = virtio_transport_send_pkt,
};

static int virtio_vsock_probe(struct virtio_device *vdev)
{
	vq_callback_t *callbacks[] = {
		virtio_vsock_rx_done,
		virtio_vsock_tx_done,
		virtio_vsock_event_done,
	};
	static const char * const names[] = {
		"rx",
		"tx",
		"event",
	};
	struct virtio_vsock *vsock = NULL;
	int ret;

	ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
	if (ret)
		return ret;

	/* Only one virtio-vsock device per guest is supported */
	if (the_virtio_vsock) {
		ret = -EBUSY;
		goto out;
	}

	vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
	if (!vsock) {
		ret = -ENOMEM;
		goto out;
	}

	vsock->vdev = vdev;

	ret = virtio_find_vqs(vsock->vdev, VSOCK_VQ_MAX,
			      vsock->vqs, callbacks, names,
			      NULL);
	if (ret < 0)
		goto out;

	virtio_vsock_update_guest_cid(vsock);

	ret = vsock_core_init(&virtio_transport.transport);
	if (ret < 0)
		goto out_vqs;

	vsock->rx_buf_nr = 0;
	vsock->rx_buf_max_nr = 0;
	atomic_set(&vsock->queued_replies, 0);

	vdev->priv = vsock;
	the_virtio_vsock = vsock;
	mutex_init(&vsock->tx_lock);
	mutex_init(&vsock->rx_lock);
	mutex_init(&vsock->event_lock);
	spin_lock_init(&vsock->send_pkt_list_lock);
	INIT_LIST_HEAD(&vsock->send_pkt_list);
	spin_lock_init(&vsock->loopback_list_lock);
	INIT_LIST_HEAD(&vsock->loopback_list);
	INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);
	INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);
	INIT_WORK(&vsock->event_work, virtio_transport_event_work);
	INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
	INIT_WORK(&vsock->loopback_work, virtio_transport_loopback_work);

	mutex_lock(&vsock->rx_lock);
	virtio_vsock_rx_fill(vsock);
	mutex_unlock(&vsock->rx_lock);

	mutex_lock(&vsock->event_lock);
	virtio_vsock_event_fill(vsock);
	mutex_unlock(&vsock->event_lock);

	mutex_unlock(&the_virtio_vsock_mutex);
	return 0;

out_vqs:
	vsock->vdev->config->del_vqs(vsock->vdev);
out:
	kfree(vsock);
	mutex_unlock(&the_virtio_vsock_mutex);
	return ret;
}

static void virtio_vsock_remove(struct virtio_device *vdev)
{
	struct virtio_vsock *vsock = vdev->priv;
	struct virtio_vsock_pkt *pkt;

	flush_work(&vsock->loopback_work);
	flush_work(&vsock->rx_work);
	flush_work(&vsock->tx_work);
	flush_work(&vsock->event_work);
	flush_work(&vsock->send_pkt_work);

	vdev->config->reset(vdev);

	mutex_lock(&vsock->rx_lock);
	while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))
		virtio_transport_free_pkt(pkt);
	mutex_unlock(&vsock->rx_lock);

	mutex_lock(&vsock->tx_lock);
	while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX])))
		virtio_transport_free_pkt(pkt);
	mutex_unlock(&vsock->tx_lock);

	spin_lock_bh(&vsock->send_pkt_list_lock);
	while (!list_empty(&vsock->send_pkt_list)) {
		pkt = list_first_entry(&vsock->send_pkt_list,
				       struct virtio_vsock_pkt, list);
		list_del(&pkt->list);
		virtio_transport_free_pkt(pkt);
	}
	spin_unlock_bh(&vsock->send_pkt_list_lock);

	spin_lock_bh(&vsock->loopback_list_lock);
	while (!list_empty(&vsock->loopback_list)) {
		pkt = list_first_entry(&vsock->loopback_list,
				       struct virtio_vsock_pkt, list);
		list_del(&pkt->list);
		virtio_transport_free_pkt(pkt);
	}
	spin_unlock_bh(&vsock->loopback_list_lock);

	mutex_lock(&the_virtio_vsock_mutex);
	the_virtio_vsock = NULL;
	vsock_core_exit();
	mutex_unlock(&the_virtio_vsock_mutex);

	vdev->config->del_vqs(vdev);

	kfree(vsock);
}

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

static unsigned int features[] = {
};

static struct virtio_driver virtio_vsock_driver = {
	.feature_table = features,
	.feature_table_size = ARRAY_SIZE(features),
	.driver.name = KBUILD_MODNAME,
	.driver.owner = THIS_MODULE,
	.id_table = id_table,
	.probe = virtio_vsock_probe,
	.remove = virtio_vsock_remove,
};

static int __init virtio_vsock_init(void)
{
	int ret;

	virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0);
	if (!virtio_vsock_workqueue)
		return -ENOMEM;
	ret = register_virtio_driver(&virtio_vsock_driver);
	if (ret)
		destroy_workqueue(virtio_vsock_workqueue);
	return ret;
}

static void __exit virtio_vsock_exit(void)
{
	unregister_virtio_driver(&virtio_vsock_driver);
	destroy_workqueue(virtio_vsock_workqueue);
}

module_init(virtio_vsock_init);
module_exit(virtio_vsock_exit);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Asias He");
MODULE_DESCRIPTION("virtio transport for vsock");
MODULE_DEVICE_TABLE(virtio, id_table);
Commit	Line	Data
0ea9e1d3 AH	1	/*
	2	* virtio transport for vsock
	3	*
	4	* Copyright (C) 2013-2015 Red Hat, Inc.
	5	* Author: Asias He <[email protected]>
	6	* Stefan Hajnoczi <[email protected]>
	7	*
	8	* Some of the code is take from Gerd Hoffmann <[email protected]>'s
	9	* early virtio-vsock proof-of-concept bits.
	10	*
	11	* This work is licensed under the terms of the GNU GPL, version 2.
	12	*/
	13	#include <linux/spinlock.h>
	14	#include <linux/module.h>
	15	#include <linux/list.h>
	16	#include <linux/atomic.h>
	17	#include <linux/virtio.h>
	18	#include <linux/virtio_ids.h>
	19	#include <linux/virtio_config.h>
	20	#include <linux/virtio_vsock.h>
	21	#include <net/sock.h>
	22	#include <linux/mutex.h>
	23	#include <net/af_vsock.h>
	24
	25	static struct workqueue_struct *virtio_vsock_workqueue;
	26	static struct virtio_vsock *the_virtio_vsock;
	27	static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */
	28
	29	struct virtio_vsock {
	30	struct virtio_device *vdev;
	31	struct virtqueue *vqs[VSOCK_VQ_MAX];
	32
	33	/* Virtqueue processing is deferred to a workqueue */
	34	struct work_struct tx_work;
	35	struct work_struct rx_work;
	36	struct work_struct event_work;
	37
	38	/* The following fields are protected by tx_lock. vqs[VSOCK_VQ_TX]
	39	* must be accessed with tx_lock held.
	40	*/
	41	struct mutex tx_lock;
	42
	43	struct work_struct send_pkt_work;
	44	spinlock_t send_pkt_list_lock;
	45	struct list_head send_pkt_list;
	46
b9116823 SH	47	struct work_struct loopback_work;
	48	spinlock_t loopback_list_lock; /* protects loopback_list */
	49	struct list_head loopback_list;
	50
0ea9e1d3 AH	51	atomic_t queued_replies;
	52
	53	/* The following fields are protected by rx_lock. vqs[VSOCK_VQ_RX]
	54	* must be accessed with rx_lock held.
	55	*/
	56	struct mutex rx_lock;
	57	int rx_buf_nr;
	58	int rx_buf_max_nr;
	59
	60	/* The following fields are protected by event_lock.
	61	* vqs[VSOCK_VQ_EVENT] must be accessed with event_lock held.
	62	*/
	63	struct mutex event_lock;
	64	struct virtio_vsock_event event_list[8];
	65
	66	u32 guest_cid;
	67	};
	68
	69	static struct virtio_vsock *virtio_vsock_get(void)
	70	{
	71	return the_virtio_vsock;
	72	}
	73
	74	static u32 virtio_transport_get_local_cid(void)
	75	{
	76	struct virtio_vsock *vsock = virtio_vsock_get();
	77
	78	return vsock->guest_cid;
	79	}
	80
b9116823 SH	81	static void virtio_transport_loopback_work(struct work_struct *work)
	82	{
	83	struct virtio_vsock *vsock =
	84	container_of(work, struct virtio_vsock, loopback_work);
	85	LIST_HEAD(pkts);
	86
	87	spin_lock_bh(&vsock->loopback_list_lock);
	88	list_splice_init(&vsock->loopback_list, &pkts);
	89	spin_unlock_bh(&vsock->loopback_list_lock);
	90
	91	mutex_lock(&vsock->rx_lock);
	92	while (!list_empty(&pkts)) {
	93	struct virtio_vsock_pkt *pkt;
	94
	95	pkt = list_first_entry(&pkts, struct virtio_vsock_pkt, list);
	96	list_del_init(&pkt->list);
	97
	98	virtio_transport_recv_pkt(pkt);
	99	}
	100	mutex_unlock(&vsock->rx_lock);
	101	}
	102
	103	static int virtio_transport_send_pkt_loopback(struct virtio_vsock *vsock,
	104	struct virtio_vsock_pkt *pkt)
	105	{
	106	int len = pkt->len;
	107
	108	spin_lock_bh(&vsock->loopback_list_lock);
	109	list_add_tail(&pkt->list, &vsock->loopback_list);
	110	spin_unlock_bh(&vsock->loopback_list_lock);
	111
	112	queue_work(virtio_vsock_workqueue, &vsock->loopback_work);
	113
	114	return len;
	115	}
	116
0ea9e1d3 AH	117	static void
	118	virtio_transport_send_pkt_work(struct work_struct *work)
	119	{
	120	struct virtio_vsock *vsock =
	121	container_of(work, struct virtio_vsock, send_pkt_work);
	122	struct virtqueue *vq;
	123	bool added = false;
	124	bool restart_rx = false;
	125
	126	mutex_lock(&vsock->tx_lock);
	127
	128	vq = vsock->vqs[VSOCK_VQ_TX];
	129
0ea9e1d3 AH	130	for (;;) {
	131	struct virtio_vsock_pkt *pkt;
	132	struct scatterlist hdr, buf, *sgs[2];
	133	int ret, in_sg = 0, out_sg = 0;
	134	bool reply;
	135
	136	spin_lock_bh(&vsock->send_pkt_list_lock);
	137	if (list_empty(&vsock->send_pkt_list)) {
	138	spin_unlock_bh(&vsock->send_pkt_list_lock);
0ea9e1d3 AH	139	break;
	140	}
	141
	142	pkt = list_first_entry(&vsock->send_pkt_list,
	143	struct virtio_vsock_pkt, list);
	144	list_del_init(&pkt->list);
	145	spin_unlock_bh(&vsock->send_pkt_list_lock);
	146
82dfb540 GG	147	virtio_transport_deliver_tap_pkt(pkt);
82dfb540 GG	148
0ea9e1d3 AH	149	reply = pkt->reply;
	150
	151	sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
	152	sgs[out_sg++] = &hdr;
	153	if (pkt->buf) {
	154	sg_init_one(&buf, pkt->buf, pkt->len);
	155	sgs[out_sg++] = &buf;
	156	}
	157
	158	ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, pkt, GFP_KERNEL);
21bc54fc GG	159	/* Usually this means that there is no more space available in
	160	* the vq
	161	*/
0ea9e1d3 AH	162	if (ret < 0) {
	163	spin_lock_bh(&vsock->send_pkt_list_lock);
	164	list_add(&pkt->list, &vsock->send_pkt_list);
	165	spin_unlock_bh(&vsock->send_pkt_list_lock);
0ea9e1d3 AH	166	break;
	167	}
	168
	169	if (reply) {
	170	struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
	171	int val;
	172
	173	val = atomic_dec_return(&vsock->queued_replies);
	174
	175	/* Do we now have resources to resume rx processing? */
	176	if (val + 1 == virtqueue_get_vring_size(rx_vq))
	177	restart_rx = true;
	178	}
	179
	180	added = true;
	181	}
	182
	183	if (added)
	184	virtqueue_kick(vq);
	185
	186	mutex_unlock(&vsock->tx_lock);
	187
	188	if (restart_rx)
	189	queue_work(virtio_vsock_workqueue, &vsock->rx_work);
	190	}
	191
	192	static int
	193	virtio_transport_send_pkt(struct virtio_vsock_pkt *pkt)
	194	{
	195	struct virtio_vsock *vsock;
	196	int len = pkt->len;
	197
	198	vsock = virtio_vsock_get();
	199	if (!vsock) {
	200	virtio_transport_free_pkt(pkt);
	201	return -ENODEV;
	202	}
	203
b9116823 SH	204	if (le32_to_cpu(pkt->hdr.dst_cid) == vsock->guest_cid)
	205	return virtio_transport_send_pkt_loopback(vsock, pkt);
	206
0ea9e1d3 AH	207	if (pkt->reply)
	208	atomic_inc(&vsock->queued_replies);
	209
	210	spin_lock_bh(&vsock->send_pkt_list_lock);
	211	list_add_tail(&pkt->list, &vsock->send_pkt_list);
	212	spin_unlock_bh(&vsock->send_pkt_list_lock);
	213
	214	queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
	215	return len;
	216	}
	217
073b4f2c PT	218	static int
	219	virtio_transport_cancel_pkt(struct vsock_sock *vsk)
	220	{
	221	struct virtio_vsock *vsock;
	222	struct virtio_vsock_pkt pkt, n;
	223	int cnt = 0;
	224	LIST_HEAD(freeme);
	225
	226	vsock = virtio_vsock_get();
	227	if (!vsock) {
	228	return -ENODEV;
	229	}
	230
	231	spin_lock_bh(&vsock->send_pkt_list_lock);
	232	list_for_each_entry_safe(pkt, n, &vsock->send_pkt_list, list) {
	233	if (pkt->vsk != vsk)
	234	continue;
	235	list_move(&pkt->list, &freeme);
	236	}
	237	spin_unlock_bh(&vsock->send_pkt_list_lock);
	238
	239	list_for_each_entry_safe(pkt, n, &freeme, list) {
	240	if (pkt->reply)
	241	cnt++;
	242	list_del(&pkt->list);
	243	virtio_transport_free_pkt(pkt);
	244	}
	245
	246	if (cnt) {
	247	struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
	248	int new_cnt;
	249
	250	new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);
	251	if (new_cnt + cnt >= virtqueue_get_vring_size(rx_vq) &&
	252	new_cnt < virtqueue_get_vring_size(rx_vq))
	253	queue_work(virtio_vsock_workqueue, &vsock->rx_work);
	254	}
	255
	256	return 0;
	257	}
	258
0ea9e1d3 AH	259	static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
	260	{
	261	int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
	262	struct virtio_vsock_pkt *pkt;
	263	struct scatterlist hdr, buf, *sgs[2];
	264	struct virtqueue *vq;
	265	int ret;
	266
	267	vq = vsock->vqs[VSOCK_VQ_RX];
	268
	269	do {
	270	pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
	271	if (!pkt)
	272	break;
	273
	274	pkt->buf = kmalloc(buf_len, GFP_KERNEL);
	275	if (!pkt->buf) {
	276	virtio_transport_free_pkt(pkt);
	277	break;
	278	}
	279
	280	pkt->len = buf_len;
	281
	282	sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
	283	sgs[0] = &hdr;
	284
	285	sg_init_one(&buf, pkt->buf, buf_len);
	286	sgs[1] = &buf;
	287	ret = virtqueue_add_sgs(vq, sgs, 0, 2, pkt, GFP_KERNEL);
	288	if (ret) {
	289	virtio_transport_free_pkt(pkt);
	290	break;
	291	}
	292	vsock->rx_buf_nr++;
	293	} while (vq->num_free);
	294	if (vsock->rx_buf_nr > vsock->rx_buf_max_nr)
	295	vsock->rx_buf_max_nr = vsock->rx_buf_nr;
	296	virtqueue_kick(vq);
	297	}
	298
	299	static void virtio_transport_tx_work(struct work_struct *work)
	300	{
	301	struct virtio_vsock *vsock =
	302	container_of(work, struct virtio_vsock, tx_work);
	303	struct virtqueue *vq;
	304	bool added = false;
	305
	306	vq = vsock->vqs[VSOCK_VQ_TX];
	307	mutex_lock(&vsock->tx_lock);
	308	do {
	309	struct virtio_vsock_pkt *pkt;
	310	unsigned int len;
	311
	312	virtqueue_disable_cb(vq);
	313	while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
	314	virtio_transport_free_pkt(pkt);
	315	added = true;
	316	}
	317	} while (!virtqueue_enable_cb(vq));
	318	mutex_unlock(&vsock->tx_lock);
	319
	320	if (added)
	321	queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
	322	}
323
324	/* Is there space left for replies to rx packets? */
325	static bool virtio_transport_more_replies(struct virtio_vsock *vsock)
326	{
327	struct virtqueue *vq = vsock->vqs[VSOCK_VQ_RX];
328	int val;
329
330	smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
331	val = atomic_read(&vsock->queued_replies);
332
333	return val < virtqueue_get_vring_size(vq);
334	}
335
336	static void virtio_transport_rx_work(struct work_struct *work)
337	{
338	struct virtio_vsock *vsock =
339	container_of(work, struct virtio_vsock, rx_work);
340	struct virtqueue *vq;
341
342	vq = vsock->vqs[VSOCK_VQ_RX];
343
344	mutex_lock(&vsock->rx_lock);
345
346	do {
347	virtqueue_disable_cb(vq);
348	for (;;) {
349	struct virtio_vsock_pkt *pkt;
350	unsigned int len;
351
352	if (!virtio_transport_more_replies(vsock)) {
353	/* Stop rx until the device processes already
354	* pending replies. Leave rx virtqueue
355	* callbacks disabled.
356	*/
357	goto out;
358	}
359
360	pkt = virtqueue_get_buf(vq, &len);
361	if (!pkt) {
362	break;
363	}
364
365	vsock->rx_buf_nr--;
366
367	/* Drop short/long packets */
368	if (unlikely(len < sizeof(pkt->hdr) \|\|
369	len > sizeof(pkt->hdr) + pkt->len)) {
370	virtio_transport_free_pkt(pkt);
371	continue;
372	}
373
374	pkt->len = len - sizeof(pkt->hdr);
82dfb540	375	virtio_transport_deliver_tap_pkt(pkt);
0ea9e1d3 AH	376	virtio_transport_recv_pkt(pkt);
	377	}
	378	} while (!virtqueue_enable_cb(vq));
	379
	380	out:
	381	if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
	382	virtio_vsock_rx_fill(vsock);
	383	mutex_unlock(&vsock->rx_lock);
	384	}
	385
	386	/* event_lock must be held */
	387	static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock,
	388	struct virtio_vsock_event *event)
	389	{
	390	struct scatterlist sg;
	391	struct virtqueue *vq;
	392
	393	vq = vsock->vqs[VSOCK_VQ_EVENT];
	394
	395	sg_init_one(&sg, event, sizeof(*event));
	396
	397	return virtqueue_add_inbuf(vq, &sg, 1, event, GFP_KERNEL);
	398	}
	399
	400	/* event_lock must be held */
	401	static void virtio_vsock_event_fill(struct virtio_vsock *vsock)
	402	{
	403	size_t i;
	404
	405	for (i = 0; i < ARRAY_SIZE(vsock->event_list); i++) {
	406	struct virtio_vsock_event *event = &vsock->event_list[i];
	407
	408	virtio_vsock_event_fill_one(vsock, event);
	409	}
	410
	411	virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
	412	}
	413
	414	static void virtio_vsock_reset_sock(struct sock *sk)
	415	{
	416	lock_sock(sk);
	417	sk->sk_state = SS_UNCONNECTED;
	418	sk->sk_err = ECONNRESET;
	419	sk->sk_error_report(sk);
	420	release_sock(sk);
	421	}
	422
	423	static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock)
	424	{
	425	struct virtio_device *vdev = vsock->vdev;
6c7efafd	426	__le64 guest_cid;
0ea9e1d3 AH	427
	428	vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),
	429	&guest_cid, sizeof(guest_cid));
	430	vsock->guest_cid = le64_to_cpu(guest_cid);
	431	}
	432
	433	/* event_lock must be held */
	434	static void virtio_vsock_event_handle(struct virtio_vsock *vsock,
	435	struct virtio_vsock_event *event)
	436	{
	437	switch (le32_to_cpu(event->id)) {
	438	case VIRTIO_VSOCK_EVENT_TRANSPORT_RESET:
	439	virtio_vsock_update_guest_cid(vsock);
	440	vsock_for_each_connected_socket(virtio_vsock_reset_sock);
	441	break;
	442	}
	443	}
	444
	445	static void virtio_transport_event_work(struct work_struct *work)
	446	{
	447	struct virtio_vsock *vsock =
	448	container_of(work, struct virtio_vsock, event_work);
	449	struct virtqueue *vq;
	450
	451	vq = vsock->vqs[VSOCK_VQ_EVENT];
	452
	453	mutex_lock(&vsock->event_lock);
	454
	455	do {
	456	struct virtio_vsock_event *event;
	457	unsigned int len;
	458
	459	virtqueue_disable_cb(vq);
	460	while ((event = virtqueue_get_buf(vq, &len)) != NULL) {
	461	if (len == sizeof(*event))
	462	virtio_vsock_event_handle(vsock, event);
	463
	464	virtio_vsock_event_fill_one(vsock, event);
	465	}
	466	} while (!virtqueue_enable_cb(vq));
	467
	468	virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
	469
	470	mutex_unlock(&vsock->event_lock);
	471	}
	472
	473	static void virtio_vsock_event_done(struct virtqueue *vq)
	474	{
	475	struct virtio_vsock *vsock = vq->vdev->priv;
	476
	477	if (!vsock)
	478	return;
	479	queue_work(virtio_vsock_workqueue, &vsock->event_work);
	480	}
	481
	482	static void virtio_vsock_tx_done(struct virtqueue *vq)
	483	{
	484	struct virtio_vsock *vsock = vq->vdev->priv;
	485
	486	if (!vsock)
	487	return;
	488	queue_work(virtio_vsock_workqueue, &vsock->tx_work);
	489	}
	490
491	static void virtio_vsock_rx_done(struct virtqueue *vq)
492	{
493	struct virtio_vsock *vsock = vq->vdev->priv;
494
495	if (!vsock)
496	return;
497	queue_work(virtio_vsock_workqueue, &vsock->rx_work);
498	}
499
500	static struct virtio_transport virtio_transport = {
501	.transport = {
502	.get_local_cid = virtio_transport_get_local_cid,
503
504	.init = virtio_transport_do_socket_init,
505	.destruct = virtio_transport_destruct,
506	.release = virtio_transport_release,
507	.connect = virtio_transport_connect,
508	.shutdown = virtio_transport_shutdown,
073b4f2c	509	.cancel_pkt = virtio_transport_cancel_pkt,
0ea9e1d3 AH	510
	511	.dgram_bind = virtio_transport_dgram_bind,
	512	.dgram_dequeue = virtio_transport_dgram_dequeue,
	513	.dgram_enqueue = virtio_transport_dgram_enqueue,
	514	.dgram_allow = virtio_transport_dgram_allow,
	515
	516	.stream_dequeue = virtio_transport_stream_dequeue,
	517	.stream_enqueue = virtio_transport_stream_enqueue,
	518	.stream_has_data = virtio_transport_stream_has_data,
	519	.stream_has_space = virtio_transport_stream_has_space,
	520	.stream_rcvhiwat = virtio_transport_stream_rcvhiwat,
	521	.stream_is_active = virtio_transport_stream_is_active,
	522	.stream_allow = virtio_transport_stream_allow,
	523
	524	.notify_poll_in = virtio_transport_notify_poll_in,
	525	.notify_poll_out = virtio_transport_notify_poll_out,
	526	.notify_recv_init = virtio_transport_notify_recv_init,
	527	.notify_recv_pre_block = virtio_transport_notify_recv_pre_block,
	528	.notify_recv_pre_dequeue = virtio_transport_notify_recv_pre_dequeue,
	529	.notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
	530	.notify_send_init = virtio_transport_notify_send_init,
	531	.notify_send_pre_block = virtio_transport_notify_send_pre_block,
	532	.notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue,
	533	.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
	534
	535	.set_buffer_size = virtio_transport_set_buffer_size,
	536	.set_min_buffer_size = virtio_transport_set_min_buffer_size,
	537	.set_max_buffer_size = virtio_transport_set_max_buffer_size,
	538	.get_buffer_size = virtio_transport_get_buffer_size,
	539	.get_min_buffer_size = virtio_transport_get_min_buffer_size,
	540	.get_max_buffer_size = virtio_transport_get_max_buffer_size,
	541	},
	542
	543	.send_pkt = virtio_transport_send_pkt,
	544	};
	545
	546	static int virtio_vsock_probe(struct virtio_device *vdev)
	547	{
	548	vq_callback_t *callbacks[] = {
	549	virtio_vsock_rx_done,
	550	virtio_vsock_tx_done,
	551	virtio_vsock_event_done,
	552	};
	553	static const char * const names[] = {
	554	"rx",
	555	"tx",
	556	"event",
	557	};
	558	struct virtio_vsock *vsock = NULL;
	559	int ret;
	560
	561	ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
	562	if (ret)
	563	return ret;
	564
	565	/* Only one virtio-vsock device per guest is supported */
	566	if (the_virtio_vsock) {
	567	ret = -EBUSY;
	568	goto out;
	569	}
	570
	571	vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
	572	if (!vsock) {
	573	ret = -ENOMEM;
574	goto out;
575	}
576
577	vsock->vdev = vdev;
578
9b2bbdb2 MT	579	ret = virtio_find_vqs(vsock->vdev, VSOCK_VQ_MAX,
	580	vsock->vqs, callbacks, names,
	581	NULL);
0ea9e1d3 AH	582	if (ret < 0)
	583	goto out;
	584
	585	virtio_vsock_update_guest_cid(vsock);
	586
	587	ret = vsock_core_init(&virtio_transport.transport);
	588	if (ret < 0)
	589	goto out_vqs;
	590
	591	vsock->rx_buf_nr = 0;
	592	vsock->rx_buf_max_nr = 0;
	593	atomic_set(&vsock->queued_replies, 0);
	594
	595	vdev->priv = vsock;
	596	the_virtio_vsock = vsock;
	597	mutex_init(&vsock->tx_lock);
	598	mutex_init(&vsock->rx_lock);
	599	mutex_init(&vsock->event_lock);
	600	spin_lock_init(&vsock->send_pkt_list_lock);
	601	INIT_LIST_HEAD(&vsock->send_pkt_list);
b9116823 SH	602	spin_lock_init(&vsock->loopback_list_lock);
b9116823 SH	603	INIT_LIST_HEAD(&vsock->loopback_list);
0ea9e1d3 AH	604	INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);
	605	INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);
	606	INIT_WORK(&vsock->event_work, virtio_transport_event_work);
	607	INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
b9116823	608	INIT_WORK(&vsock->loopback_work, virtio_transport_loopback_work);
0ea9e1d3 AH	609
	610	mutex_lock(&vsock->rx_lock);
	611	virtio_vsock_rx_fill(vsock);
	612	mutex_unlock(&vsock->rx_lock);
	613
	614	mutex_lock(&vsock->event_lock);
	615	virtio_vsock_event_fill(vsock);
	616	mutex_unlock(&vsock->event_lock);
	617
	618	mutex_unlock(&the_virtio_vsock_mutex);
	619	return 0;
	620
	621	out_vqs:
	622	vsock->vdev->config->del_vqs(vsock->vdev);
	623	out:
	624	kfree(vsock);
	625	mutex_unlock(&the_virtio_vsock_mutex);
	626	return ret;
	627	}
	628
	629	static void virtio_vsock_remove(struct virtio_device *vdev)
	630	{
	631	struct virtio_vsock *vsock = vdev->priv;
	632	struct virtio_vsock_pkt *pkt;
	633
b9116823	634	flush_work(&vsock->loopback_work);
0ea9e1d3 AH	635	flush_work(&vsock->rx_work);
	636	flush_work(&vsock->tx_work);
	637	flush_work(&vsock->event_work);
	638	flush_work(&vsock->send_pkt_work);
	639
	640	vdev->config->reset(vdev);
	641
	642	mutex_lock(&vsock->rx_lock);
	643	while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))
	644	virtio_transport_free_pkt(pkt);
	645	mutex_unlock(&vsock->rx_lock);
	646
	647	mutex_lock(&vsock->tx_lock);
	648	while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX])))
	649	virtio_transport_free_pkt(pkt);
	650	mutex_unlock(&vsock->tx_lock);
	651
	652	spin_lock_bh(&vsock->send_pkt_list_lock);
	653	while (!list_empty(&vsock->send_pkt_list)) {
	654	pkt = list_first_entry(&vsock->send_pkt_list,
	655	struct virtio_vsock_pkt, list);
	656	list_del(&pkt->list);
	657	virtio_transport_free_pkt(pkt);
	658	}
	659	spin_unlock_bh(&vsock->send_pkt_list_lock);
	660
b9116823 SH	661	spin_lock_bh(&vsock->loopback_list_lock);
	662	while (!list_empty(&vsock->loopback_list)) {
	663	pkt = list_first_entry(&vsock->loopback_list,
	664	struct virtio_vsock_pkt, list);
	665	list_del(&pkt->list);
	666	virtio_transport_free_pkt(pkt);
	667	}
	668	spin_unlock_bh(&vsock->loopback_list_lock);
	669
0ea9e1d3 AH	670	mutex_lock(&the_virtio_vsock_mutex);
	671	the_virtio_vsock = NULL;
	672	vsock_core_exit();
	673	mutex_unlock(&the_virtio_vsock_mutex);
	674
	675	vdev->config->del_vqs(vdev);
	676
	677	kfree(vsock);
	678	}
	679
	680	static struct virtio_device_id id_table[] = {
	681	{ VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID },
	682	{ 0 },
	683	};
	684
	685	static unsigned int features[] = {
	686	};
	687
	688	static struct virtio_driver virtio_vsock_driver = {
	689	.feature_table = features,
	690	.feature_table_size = ARRAY_SIZE(features),
	691	.driver.name = KBUILD_MODNAME,
	692	.driver.owner = THIS_MODULE,
	693	.id_table = id_table,
	694	.probe = virtio_vsock_probe,
	695	.remove = virtio_vsock_remove,
	696	};
	697
	698	static int __init virtio_vsock_init(void)
	699	{
	700	int ret;
	701
	702	virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0);
	703	if (!virtio_vsock_workqueue)
	704	return -ENOMEM;
	705	ret = register_virtio_driver(&virtio_vsock_driver);
	706	if (ret)
	707	destroy_workqueue(virtio_vsock_workqueue);
	708	return ret;
	709	}
	710
	711	static void __exit virtio_vsock_exit(void)
	712	{
	713	unregister_virtio_driver(&virtio_vsock_driver);
	714	destroy_workqueue(virtio_vsock_workqueue);
	715	}
	716
	717	module_init(virtio_vsock_init);
	718	module_exit(virtio_vsock_exit);
	719	MODULE_LICENSE("GPL v2");
	720	MODULE_AUTHOR("Asias He");
	721	MODULE_DESCRIPTION("virtio transport for vsock");
	722	MODULE_DEVICE_TABLE(virtio, id_table);