Subject: Re: [PATCH v3 1/4] VSOCK: Introduce virtio-vsock-common.ko

From: Alex Bennée <[email-masked]>
Date: Thu, 10 Dec 2015 10:17:07 +0000

Stefan Hajnoczi <[email-masked]> writes:

> From: Asias He <[email-masked]>
>
> This module contains the common code and header files for the following
> virtio-vsock and virtio-vhost kernel modules.

General comment checkpatch has a bunch of warnings about 80 character
limits, extra braces and BUG_ON usage.

>
> Signed-off-by: Asias He <[email-masked]>
> Signed-off-by: Stefan Hajnoczi <[email-masked]>
> ---
> v3:
>  * Remove unnecessary 3-way handshake, just do REQUEST/RESPONSE instead
>    of REQUEST/RESPONSE/ACK
>  * Remove SOCK_DGRAM support and focus on SOCK_STREAM first
>  * Only allow host->guest connections (same security model as latest
>    VMware)
> v2:
>  * Fix peer_buf_alloc inheritance on child socket
>  * Notify other side of SOCK_STREAM disconnect (fixes shutdown
>    semantics)
>  * Avoid recursive mutex_lock(tx_lock) for write_space (fixes deadlock)
>  * Define VIRTIO_VSOCK_TYPE_STREAM/DGRAM hardware interface constants
>  * Define VIRTIO_VSOCK_SHUTDOWN_RCV/SEND hardware interface constants
> ---
>  include/linux/virtio_vsock.h            | 203 ++++++++
>  include/uapi/linux/virtio_ids.h         |   1 +
>  include/uapi/linux/virtio_vsock.h       |  87 ++++
>  net/vmw_vsock/virtio_transport_common.c | 854 ++++++++++++++++++++++++++++++++
>  4 files changed, 1145 insertions(+)
>  create mode 100644 include/linux/virtio_vsock.h
>  create mode 100644 include/uapi/linux/virtio_vsock.h
>  create mode 100644 net/vmw_vsock/virtio_transport_common.c
>
> diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
> new file mode 100644
> index 0000000..e54eb45
> --- /dev/null
> +++ b/include/linux/virtio_vsock.h
> @@ -0,0 +1,203 @@
> +/*
> + * This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
> + * anyone can use the definitions to implement compatible
> drivers/servers:

Is anything in here actually exposed to userspace or the guest? The
#ifdef __KERNEL__ statement seems redundant for this file at least.

> + *
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:
> + * 1. Redistributions of source code must retain the above copyright
> + *    notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + *    notice, this list of conditions and the following disclaimer in the
> + *    documentation and/or other materials provided with the distribution.
> + * 3. Neither the name of IBM nor the names of its contributors
> + *    may be used to endorse or promote products derived from this software
> + *    without specific prior written permission.
> + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
> + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> + * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
> + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
> + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
> + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
> + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
> + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> + * SUCH DAMAGE.
> + *
> + * Copyright (C) Red Hat, Inc., 2013-2015
> + * Copyright (C) Asias He <[email-masked]>, 2013
> + * Copyright (C) Stefan Hajnoczi <[email-masked]>, 2015
> + */
> +
> +#ifndef _LINUX_VIRTIO_VSOCK_H
> +#define _LINUX_VIRTIO_VSOCK_H
> +
> +#include <uapi/linux/virtio_vsock.h>
> +#include <linux/socket.h>
> +#include <net/sock.h>
> +
> +#define VIRTIO_VSOCK_DEFAULT_MIN_BUF_SIZE	128
> +#define VIRTIO_VSOCK_DEFAULT_BUF_SIZE		(1024 * 256)
> +#define VIRTIO_VSOCK_DEFAULT_MAX_BUF_SIZE	(1024 * 256)
> +#define VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE	(1024 * 4)
> +#define VIRTIO_VSOCK_MAX_BUF_SIZE		0xFFFFFFFFUL
> +#define VIRTIO_VSOCK_MAX_PKT_BUF_SIZE		(1024 * 64)
> +#define VIRTIO_VSOCK_MAX_TX_BUF_SIZE		(1024 * 1024 * 16)
> +#define VIRTIO_VSOCK_MAX_DGRAM_SIZE		(1024 * 64)
> +
> +struct vsock_transport_recv_notify_data;
> +struct vsock_transport_send_notify_data;
> +struct sockaddr_vm;
> +struct vsock_sock;
> +
> +enum {
> +	VSOCK_VQ_CTRL	= 0,
> +	VSOCK_VQ_RX	= 1, /* for host to guest data */
> +	VSOCK_VQ_TX	= 2, /* for guest to host data */
> +	VSOCK_VQ_MAX	= 3,
> +};
> +
> +/* virtio transport socket state */
> +struct virtio_transport {
> +	struct virtio_transport_pkt_ops	*ops;
> +	struct vsock_sock *vsk;
> +
> +	u32 buf_size;
> +	u32 buf_size_min;
> +	u32 buf_size_max;
> +
> +	struct mutex tx_lock;
> +	struct mutex rx_lock;
> +
> +	struct list_head rx_queue;
> +	u32 rx_bytes;
> +
> +	/* Protected by trans->tx_lock */
> +	u32 tx_cnt;
> +	u32 buf_alloc;
> +	u32 peer_fwd_cnt;
> +	u32 peer_buf_alloc;
> +	/* Protected by trans->rx_lock */
> +	u32 fwd_cnt;
> +};
> +
> +struct virtio_vsock_pkt {
> +	struct virtio_vsock_hdr	hdr;
> +	struct virtio_transport	*trans;
> +	struct work_struct work;
> +	struct list_head list;
> +	void *buf;
> +	u32 len;
> +	u32 off;
> +};
> +
> +struct virtio_vsock_pkt_info {
> +	u32 remote_cid, remote_port;
> +	struct msghdr *msg;
> +	u32 pkt_len;
> +	u16 type;
> +	u16 op;
> +	u32 flags;
> +};
> +
> +struct virtio_transport_pkt_ops {
> +	int (*send_pkt)(struct vsock_sock *vsk,
> +			struct virtio_vsock_pkt_info *info);
> +};
> +
> +void virtio_vsock_dumppkt(const char *func,
> +			  const struct virtio_vsock_pkt *pkt);
> +
> +struct sock *
> +virtio_transport_get_pending(struct sock *listener,
> +			     struct virtio_vsock_pkt *pkt);
> +struct virtio_vsock_pkt *
> +virtio_transport_alloc_pkt(struct vsock_sock *vsk,
> +			   struct virtio_vsock_pkt_info *info,
> +			   size_t len,
> +			   u32 src_cid,
> +			   u32 src_port,
> +			   u32 dst_cid,
> +			   u32 dst_port);
> +ssize_t
> +virtio_transport_stream_dequeue(struct vsock_sock *vsk,
> +				struct msghdr *msg,
> +				size_t len,
> +				int type);
> +int
> +virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
> +			       struct msghdr *msg,
> +			       size_t len, int flags);
> +
> +s64 virtio_transport_stream_has_data(struct vsock_sock *vsk);
> +s64 virtio_transport_stream_has_space(struct vsock_sock *vsk);
> +
> +int virtio_transport_do_socket_init(struct vsock_sock *vsk,
> +				 struct vsock_sock *psk);
> +u64 virtio_transport_get_buffer_size(struct vsock_sock *vsk);
> +u64 virtio_transport_get_min_buffer_size(struct vsock_sock *vsk);
> +u64 virtio_transport_get_max_buffer_size(struct vsock_sock *vsk);
> +void virtio_transport_set_buffer_size(struct vsock_sock *vsk, u64 val);
> +void virtio_transport_set_min_buffer_size(struct vsock_sock *vsk, u64 val);
> +void virtio_transport_set_max_buffer_size(struct vsock_sock *vs, u64 val);
> +int
> +virtio_transport_notify_poll_in(struct vsock_sock *vsk,
> +				size_t target,
> +				bool *data_ready_now);
> +int
> +virtio_transport_notify_poll_out(struct vsock_sock *vsk,
> +				 size_t target,
> +				 bool *space_available_now);
> +
> +int virtio_transport_notify_recv_init(struct vsock_sock *vsk,
> +	size_t target, struct vsock_transport_recv_notify_data *data);
> +int virtio_transport_notify_recv_pre_block(struct vsock_sock *vsk,
> +	size_t target, struct vsock_transport_recv_notify_data *data);
> +int virtio_transport_notify_recv_pre_dequeue(struct vsock_sock *vsk,
> +	size_t target, struct vsock_transport_recv_notify_data *data);
> +int virtio_transport_notify_recv_post_dequeue(struct vsock_sock *vsk,
> +	size_t target, ssize_t copied, bool data_read,
> +	struct vsock_transport_recv_notify_data *data);
> +int virtio_transport_notify_send_init(struct vsock_sock *vsk,
> +	struct vsock_transport_send_notify_data *data);
> +int virtio_transport_notify_send_pre_block(struct vsock_sock *vsk,
> +	struct vsock_transport_send_notify_data *data);
> +int virtio_transport_notify_send_pre_enqueue(struct vsock_sock *vsk,
> +	struct vsock_transport_send_notify_data *data);
> +int virtio_transport_notify_send_post_enqueue(struct vsock_sock *vsk,
> +	ssize_t written, struct vsock_transport_send_notify_data *data);
> +
> +u64 virtio_transport_stream_rcvhiwat(struct vsock_sock *vsk);
> +bool virtio_transport_stream_is_active(struct vsock_sock *vsk);
> +bool virtio_transport_stream_allow(u32 cid, u32 port);
> +int virtio_transport_dgram_bind(struct vsock_sock *vsk,
> +				struct sockaddr_vm *addr);
> +bool virtio_transport_dgram_allow(u32 cid, u32 port);
> +
> +int virtio_transport_connect(struct vsock_sock *vsk);
> +
> +int virtio_transport_shutdown(struct vsock_sock *vsk, int mode);
> +
> +void virtio_transport_release(struct vsock_sock *vsk);
> +
> +ssize_t
> +virtio_transport_stream_enqueue(struct vsock_sock *vsk,
> +				struct msghdr *msg,
> +				size_t len);
> +int
> +virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
> +			       struct sockaddr_vm *remote_addr,
> +			       struct msghdr *msg,
> +			       size_t len);
> +
> +void virtio_transport_destruct(struct vsock_sock *vsk);
> +
> +void virtio_transport_recv_pkt(struct virtio_vsock_pkt *pkt);
> +void virtio_transport_free_pkt(struct virtio_vsock_pkt *pkt);
> +void virtio_transport_inc_tx_pkt(struct virtio_vsock_pkt *pkt);
> +void virtio_transport_dec_tx_pkt(struct virtio_vsock_pkt *pkt);
> +u32 virtio_transport_get_credit(struct virtio_transport *trans, u32 wanted);
> +void virtio_transport_put_credit(struct virtio_transport *trans, u32 credit);
> +#endif /* _LINUX_VIRTIO_VSOCK_H */
> diff --git a/include/uapi/linux/virtio_ids.h b/include/uapi/linux/virtio_ids.h
> index 77925f5..16dcf5d 100644
> --- a/include/uapi/linux/virtio_ids.h
> +++ b/include/uapi/linux/virtio_ids.h
> @@ -39,6 +39,7 @@
>  #define VIRTIO_ID_9P		9 /* 9p virtio console */
>  #define VIRTIO_ID_RPROC_SERIAL 11 /* virtio remoteproc serial link */
>  #define VIRTIO_ID_CAIF	       12 /* Virtio caif */
> +#define VIRTIO_ID_VSOCK        13 /* virtio vsock transport */
>  #define VIRTIO_ID_GPU          16 /* virtio GPU */
>  #define VIRTIO_ID_INPUT        18 /* virtio input */
>
> diff --git a/include/uapi/linux/virtio_vsock.h b/include/uapi/linux/virtio_vsock.h
> new file mode 100644
> index 0000000..ac6483d
> --- /dev/null
> +++ b/include/uapi/linux/virtio_vsock.h
> @@ -0,0 +1,87 @@
> +/*
> + * This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
> + * anyone can use the definitions to implement compatible drivers/servers:
> + *
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:
> + * 1. Redistributions of source code must retain the above copyright
> + *    notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + *    notice, this list of conditions and the following disclaimer in the
> + *    documentation and/or other materials provided with the distribution.
> + * 3. Neither the name of IBM nor the names of its contributors
> + *    may be used to endorse or promote products derived from this software
> + *    without specific prior written permission.
> + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
> + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> + * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
> + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
> + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
> + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
> + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
> + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> + * SUCH DAMAGE.
> + *
> + * Copyright (C) Red Hat, Inc., 2013-2015
> + * Copyright (C) Asias He <[email-masked]>, 2013
> + * Copyright (C) Stefan Hajnoczi <[email-masked]>, 2015
> + */
> +
> +#ifndef _UAPI_LINUX_VIRTIO_VSOCK_H
> +#define _UAPI_LINUX_VIRTIO_VOSCK_H
> +
> +#include <linux/types.h>
> +#include <linux/virtio_ids.h>
> +#include <linux/virtio_config.h>
> +
> +struct virtio_vsock_config {
> +	__le32 guest_cid;
> +	__le32 max_virtqueue_pairs;
> +};
> +
> +struct virtio_vsock_hdr {
> +	__le32	src_cid;
> +	__le32	src_port;
> +	__le32	dst_cid;
> +	__le32	dst_port;
> +	__le32	len;
> +	__le16	type;		/* enum virtio_vsock_type */
> +	__le16	op;		/* enum virtio_vsock_op */
> +	__le32	flags;
> +	__le32	buf_alloc;
> +	__le32	fwd_cnt;
> +};
> +
> +enum virtio_vsock_type {
> +	VIRTIO_VSOCK_TYPE_STREAM = 1,
> +};
> +
> +enum virtio_vsock_op {
> +	VIRTIO_VSOCK_OP_INVALID = 0,
> +
> +	/* Connect operations */
> +	VIRTIO_VSOCK_OP_REQUEST = 1,
> +	VIRTIO_VSOCK_OP_RESPONSE = 2,
> +	VIRTIO_VSOCK_OP_RST = 3,
> +	VIRTIO_VSOCK_OP_SHUTDOWN = 4,
> +
> +	/* To send payload */
> +	VIRTIO_VSOCK_OP_RW = 5,
> +
> +	/* Tell the peer our credit info */
> +	VIRTIO_VSOCK_OP_CREDIT_UPDATE = 6,
> +	/* Request the peer to send the credit info to us */
> +	VIRTIO_VSOCK_OP_CREDIT_REQUEST = 7,
> +};
> +
> +/* VIRTIO_VSOCK_OP_SHUTDOWN flags values */
> +enum virtio_vsock_shutdown {
> +	VIRTIO_VSOCK_SHUTDOWN_RCV = 1,
> +	VIRTIO_VSOCK_SHUTDOWN_SEND = 2,
> +};
> +
> +#endif /* _UAPI_LINUX_VIRTIO_VSOCK_H */
> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
> new file mode 100644
> index 0000000..025a323
> --- /dev/null
> +++ b/net/vmw_vsock/virtio_transport_common.c
> @@ -0,0 +1,854 @@
> +/*
> + * common code for virtio vsock
> + *
> + * Copyright (C) 2013-2015 Red Hat, Inc.
> + * Author: Asias He <[email-masked]>
> + *         Stefan Hajnoczi <[email-masked]>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.
> + */
> +#include <linux/module.h>
> +#include <linux/ctype.h>
> +#include <linux/list.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 <net/af_vsock.h>
> +
> +void virtio_vsock_dumppkt(const char *func,  const struct virtio_vsock_pkt *pkt)
> +{
> +	pr_debug("%s: pkt=%p, op=%d, len=%d, %d:%d---%d:%d, len=%d\n",
> +		 func, pkt,
> +		 le16_to_cpu(pkt->hdr.op),
> +		 le32_to_cpu(pkt->hdr.len),
> +		 le32_to_cpu(pkt->hdr.src_cid),
> +		 le32_to_cpu(pkt->hdr.src_port),
> +		 le32_to_cpu(pkt->hdr.dst_cid),
> +		 le32_to_cpu(pkt->hdr.dst_port),
> +		 pkt->len);
> +}
> +EXPORT_SYMBOL_GPL(virtio_vsock_dumppkt);

Why export this at all? The only users are in this file so you could
make it static.

> +
> +struct virtio_vsock_pkt *
> +virtio_transport_alloc_pkt(struct vsock_sock *vsk,
> +			   struct virtio_vsock_pkt_info *info,
> +			   size_t len,
> +			   u32 src_cid,
> +			   u32 src_port,
> +			   u32 dst_cid,
> +			   u32 dst_port)

c.f. checkpatch

> +{
> +	struct virtio_transport *trans = vsk->trans;
> +	struct virtio_vsock_pkt *pkt;
> +	int err;
> +
> +	BUG_ON(!trans);

So checkpatch flags up BUG_ON usage as a potential problem. Should a
badly configured really take out the kernel rather than gracefully warn
and fail?

> +
> +	pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
> +	if (!pkt)
> +		return NULL;
> +
> +	pkt->hdr.type		= cpu_to_le16(info->type);
> +	pkt->hdr.op		= cpu_to_le16(info->op);
> +	pkt->hdr.src_cid	= cpu_to_le32(src_cid);
> +	pkt->hdr.src_port	= cpu_to_le32(src_port);
> +	pkt->hdr.dst_cid	= cpu_to_le32(dst_cid);
> +	pkt->hdr.dst_port	= cpu_to_le32(dst_port);
> +	pkt->hdr.flags		= cpu_to_le32(info->flags);
> +	pkt->len		= len;
> +	pkt->trans		= trans;
> +	pkt->hdr.len		= cpu_to_le32(len);
> +
> +	if (info->msg && len > 0) {
> +		pkt->buf = kmalloc(len, GFP_KERNEL);
> +		if (!pkt->buf)
> +			goto out_pkt;
> +		err = memcpy_from_msg(pkt->buf, info->msg, len);
> +		if (err)
> +			goto out;
> +	}
> +
> +	return pkt;
> +
> +out:
> +	kfree(pkt->buf);
> +out_pkt:
> +	kfree(pkt);
> +	return NULL;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_alloc_pkt);
> +
> +struct sock *
> +virtio_transport_get_pending(struct sock *listener,
> +			     struct virtio_vsock_pkt *pkt)
> +{
> +	struct vsock_sock *vlistener;
> +	struct vsock_sock *vpending;
> +	struct sockaddr_vm src;
> +	struct sockaddr_vm dst;
> +	struct sock *pending;
> +
> +	vsock_addr_init(&src, le32_to_cpu(pkt->hdr.src_cid), le32_to_cpu(pkt->hdr.src_port));
> +	vsock_addr_init(&dst, le32_to_cpu(pkt->hdr.dst_cid), le32_to_cpu(pkt->hdr.dst_port));
> +
> +	vlistener = vsock_sk(listener);
> +	list_for_each_entry(vpending, &vlistener->pending_links,
> +			    pending_links) {
> +		if (vsock_addr_equals_addr(&src, &vpending->remote_addr) &&
> +		    vsock_addr_equals_addr(&dst, &vpending->local_addr)) {
> +			pending = sk_vsock(vpending);
> +			sock_hold(pending);
> +			return pending;
> +		}
> +	}
> +
> +	return NULL;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_get_pending);
> +
> +static void virtio_transport_inc_rx_pkt(struct virtio_vsock_pkt *pkt)
> +{
> +	pkt->trans->rx_bytes += pkt->len;
> +}
> +
> +static void virtio_transport_dec_rx_pkt(struct virtio_vsock_pkt *pkt)
> +{
> +	pkt->trans->rx_bytes -= pkt->len;
> +	pkt->trans->fwd_cnt += pkt->len;
> +}
> +
> +void virtio_transport_inc_tx_pkt(struct virtio_vsock_pkt *pkt)
> +{
> +	mutex_lock(&pkt->trans->tx_lock);
> +	pkt->hdr.fwd_cnt = cpu_to_le32(pkt->trans->fwd_cnt);
> +	pkt->hdr.buf_alloc = cpu_to_le32(pkt->trans->buf_alloc);
> +	mutex_unlock(&pkt->trans->tx_lock);
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_inc_tx_pkt);
> +
> +void virtio_transport_dec_tx_pkt(struct virtio_vsock_pkt *pkt)
> +{
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_dec_tx_pkt);
> +
> +u32 virtio_transport_get_credit(struct virtio_transport *trans, u32 credit)
> +{
> +	u32 ret;
> +
> +	mutex_lock(&trans->tx_lock);
> +	ret = trans->peer_buf_alloc - (trans->tx_cnt - trans->peer_fwd_cnt);
> +	if (ret > credit)
> +		ret = credit;
> +	trans->tx_cnt += ret;
> +	mutex_unlock(&trans->tx_lock);
> +
> +	pr_debug("%s: ret=%d, buf_alloc=%d, peer_buf_alloc=%d,"
> +		 "tx_cnt=%d, fwd_cnt=%d, peer_fwd_cnt=%d\n", __func__,

I think __func__ is superfluous here as the dynamic print code already
has it and can print it when required. Having said that there seems to
be plenty of code already in the kernel that uses __func__ :-/

> +		 ret, trans->buf_alloc, trans->peer_buf_alloc,
> +		 trans->tx_cnt, trans->fwd_cnt, trans->peer_fwd_cnt);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_get_credit);
> +
> +void virtio_transport_put_credit(struct virtio_transport *trans, u32 credit)
> +{
> +	mutex_lock(&trans->tx_lock);
> +	trans->tx_cnt -= credit;
> +	mutex_unlock(&trans->tx_lock);
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_put_credit);
> +
> +static int virtio_transport_send_credit_update(struct vsock_sock *vsk, int type, struct virtio_vsock_hdr *hdr)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +	struct virtio_vsock_pkt_info info = {
> +		.op = VIRTIO_VSOCK_OP_CREDIT_UPDATE,
> +		.type = type,
> +	};
> +
> +	pr_debug("%s: sk=%p send_credit_update\n", __func__, vsk);

Again superfluous __func__

> +	return trans->ops->send_pkt(vsk, &info);
> +}
> +
> +static ssize_t
> +virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
> +				   struct msghdr *msg,
> +				   size_t len)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +	struct virtio_vsock_pkt *pkt;
> +	size_t bytes, total = 0;
> +	int err = -EFAULT;
> +
> +	mutex_lock(&trans->rx_lock);
> +	while (total < len && trans->rx_bytes > 0  &&
> +			!list_empty(&trans->rx_queue)) {
> +		pkt = list_first_entry(&trans->rx_queue,
> +				       struct virtio_vsock_pkt, list);
> +
> +		bytes = len - total;
> +		if (bytes > pkt->len - pkt->off)
> +			bytes = pkt->len - pkt->off;
> +
> +		err = memcpy_to_msg(msg, pkt->buf + pkt->off, bytes);
> +		if (err)
> +			goto out;
> +		total += bytes;
> +		pkt->off += bytes;
> +		if (pkt->off == pkt->len) {
> +			virtio_transport_dec_rx_pkt(pkt);
> +			list_del(&pkt->list);
> +			virtio_transport_free_pkt(pkt);
> +		}
> +	}
> +	mutex_unlock(&trans->rx_lock);
> +
> +	/* Send a credit pkt to peer */
> +	virtio_transport_send_credit_update(vsk, VIRTIO_VSOCK_TYPE_STREAM,
> +					    NULL);
> +
> +	return total;
> +
> +out:
> +	mutex_unlock(&trans->rx_lock);
> +	if (total)
> +		err = total;
> +	return err;
> +}
> +
> +ssize_t
> +virtio_transport_stream_dequeue(struct vsock_sock *vsk,
> +				struct msghdr *msg,
> +				size_t len, int flags)
> +{
> +	if (flags & MSG_PEEK)
> +		return -EOPNOTSUPP;
> +
> +	return virtio_transport_stream_do_dequeue(vsk, msg, len);
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_stream_dequeue);
> +
> +int
> +virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
> +			       struct msghdr *msg,
> +			       size_t len, int flags)
> +{
> +	return -EOPNOTSUPP;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_dgram_dequeue);
> +
> +s64 virtio_transport_stream_has_data(struct vsock_sock *vsk)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +	s64 bytes;
> +
> +	mutex_lock(&trans->rx_lock);
> +	bytes = trans->rx_bytes;
> +	mutex_unlock(&trans->rx_lock);
> +
> +	return bytes;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_stream_has_data);
> +
> +static s64 virtio_transport_has_space(struct vsock_sock *vsk)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +	s64 bytes;
> +
> +	bytes = trans->peer_buf_alloc - (trans->tx_cnt - trans->peer_fwd_cnt);
> +	if (bytes < 0)
> +		bytes = 0;
> +
> +	return bytes;
> +}
> +
> +s64 virtio_transport_stream_has_space(struct vsock_sock *vsk)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +	s64 bytes;
> +
> +	mutex_lock(&trans->tx_lock);
> +	bytes = virtio_transport_has_space(vsk);
> +	mutex_unlock(&trans->tx_lock);
> +
> +	pr_debug("%s: bytes=%lld\n", __func__, bytes);
> +
> +	return bytes;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_stream_has_space);
> +
> +int virtio_transport_do_socket_init(struct vsock_sock *vsk,
> +				    struct vsock_sock *psk)
> +{
> +	struct virtio_transport *trans;
> +
> +	trans = kzalloc(sizeof(*trans), GFP_KERNEL);
> +	if (!trans)
> +		return -ENOMEM;
> +
> +	vsk->trans = trans;
> +	trans->vsk = vsk;
> +	if (psk) {
> +		struct virtio_transport *ptrans = psk->trans;
> +		trans->buf_size	= ptrans->buf_size;
> +		trans->buf_size_min = ptrans->buf_size_min;
> +		trans->buf_size_max = ptrans->buf_size_max;
> +		trans->peer_buf_alloc = ptrans->peer_buf_alloc;
> +	} else {
> +		trans->buf_size = VIRTIO_VSOCK_DEFAULT_BUF_SIZE;
> +		trans->buf_size_min = VIRTIO_VSOCK_DEFAULT_MIN_BUF_SIZE;
> +		trans->buf_size_max = VIRTIO_VSOCK_DEFAULT_MAX_BUF_SIZE;
> +	}
> +
> +	trans->buf_alloc = trans->buf_size;
> +
> +	pr_debug("%s: trans->buf_alloc=%d\n", __func__, trans->buf_alloc);
> +
> +	mutex_init(&trans->rx_lock);
> +	mutex_init(&trans->tx_lock);
> +	INIT_LIST_HEAD(&trans->rx_queue);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_do_socket_init);
> +
> +u64 virtio_transport_get_buffer_size(struct vsock_sock *vsk)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +
> +	return trans->buf_size;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_get_buffer_size);
> +
> +u64 virtio_transport_get_min_buffer_size(struct vsock_sock *vsk)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +
> +	return trans->buf_size_min;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_get_min_buffer_size);
> +
> +u64 virtio_transport_get_max_buffer_size(struct vsock_sock *vsk)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +
> +	return trans->buf_size_max;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_get_max_buffer_size);

All these accesses functions seem pretty simple. Maybe they should be
inline header functions or even #define macros?

> +
> +void virtio_transport_set_buffer_size(struct vsock_sock *vsk, u64 val)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +
> +	if (val > VIRTIO_VSOCK_MAX_BUF_SIZE)
> +		val = VIRTIO_VSOCK_MAX_BUF_SIZE;
> +	if (val < trans->buf_size_min)
> +		trans->buf_size_min = val;
> +	if (val > trans->buf_size_max)
> +		trans->buf_size_max = val;
> +	trans->buf_size = val;
> +	trans->buf_alloc = val;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_set_buffer_size);
> +
> +void virtio_transport_set_min_buffer_size(struct vsock_sock *vsk, u64 val)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +
> +	if (val > VIRTIO_VSOCK_MAX_BUF_SIZE)
> +		val = VIRTIO_VSOCK_MAX_BUF_SIZE;
> +	if (val > trans->buf_size)
> +		trans->buf_size = val;
> +	trans->buf_size_min = val;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_set_min_buffer_size);
> +
> +void virtio_transport_set_max_buffer_size(struct vsock_sock *vsk, u64 val)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +
> +	if (val > VIRTIO_VSOCK_MAX_BUF_SIZE)
> +		val = VIRTIO_VSOCK_MAX_BUF_SIZE;
> +	if (val < trans->buf_size)
> +		trans->buf_size = val;
> +	trans->buf_size_max = val;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_set_max_buffer_size);
> +
> +int
> +virtio_transport_notify_poll_in(struct vsock_sock *vsk,
> +				size_t target,
> +				bool *data_ready_now)

c.f. checkpatch indentation

> +{
> +	if (vsock_stream_has_data(vsk))
> +		*data_ready_now = true;
> +	else
> +		*data_ready_now = false;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_notify_poll_in);
> +
> +int
> +virtio_transport_notify_poll_out(struct vsock_sock *vsk,
> +				 size_t target,
> +				 bool *space_avail_now)

checkpatch

> +{
> +	s64 free_space;
> +
> +	free_space = vsock_stream_has_space(vsk);
> +	if (free_space > 0)
> +		*space_avail_now = true;
> +	else if (free_space == 0)
> +		*space_avail_now = false;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_notify_poll_out);
> +
> +int virtio_transport_notify_recv_init(struct vsock_sock *vsk,
> +	size_t target, struct vsock_transport_recv_notify_data *data)
> +{
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_init);
> +
> +int virtio_transport_notify_recv_pre_block(struct vsock_sock *vsk,
> +	size_t target, struct vsock_transport_recv_notify_data *data)
> +{
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_pre_block);
> +
> +int virtio_transport_notify_recv_pre_dequeue(struct vsock_sock *vsk,
> +	size_t target, struct vsock_transport_recv_notify_data *data)
> +{
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_pre_dequeue);
> +
> +int virtio_transport_notify_recv_post_dequeue(struct vsock_sock *vsk,
> +	size_t target, ssize_t copied, bool data_read,
> +	struct vsock_transport_recv_notify_data *data)
> +{
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_post_dequeue);
> +
> +int virtio_transport_notify_send_init(struct vsock_sock *vsk,
> +	struct vsock_transport_send_notify_data *data)
> +{
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_notify_send_init);
> +
> +int virtio_transport_notify_send_pre_block(struct vsock_sock *vsk,
> +	struct vsock_transport_send_notify_data *data)
> +{
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_notify_send_pre_block);
> +
> +int virtio_transport_notify_send_pre_enqueue(struct vsock_sock *vsk,
> +	struct vsock_transport_send_notify_data *data)
> +{
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_notify_send_pre_enqueue);
> +
> +int virtio_transport_notify_send_post_enqueue(struct vsock_sock *vsk,
> +	ssize_t written, struct vsock_transport_send_notify_data *data)
> +{
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_notify_send_post_enqueue);

This makes me wonder if the calling code should be having
if(transport->fn) checks rather than filling stuff out will null
implementations but I guess that's a question better aimed at the
maintainers.

> +
> +u64 virtio_transport_stream_rcvhiwat(struct vsock_sock *vsk)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +
> +	return trans->buf_size;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_stream_rcvhiwat);
> +
> +bool virtio_transport_stream_is_active(struct vsock_sock *vsk)
> +{
> +	return true;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_stream_is_active);
> +
> +bool virtio_transport_stream_allow(u32 cid, u32 port)
> +{
> +	/* Only allow guest->host connections */
> +	return cid != VMADDR_CID_HOST;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_stream_allow);
> +
> +int virtio_transport_dgram_bind(struct vsock_sock *vsk,
> +				struct sockaddr_vm *addr)
> +{
> +	return -EOPNOTSUPP;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_dgram_bind);
> +
> +bool virtio_transport_dgram_allow(u32 cid, u32 port)
> +{
> +	return false;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_dgram_allow);
> +
> +int virtio_transport_connect(struct vsock_sock *vsk)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +	struct virtio_vsock_pkt_info info = {
> +		.op = VIRTIO_VSOCK_OP_REQUEST,
> +		.type = VIRTIO_VSOCK_TYPE_STREAM,
> +	};
> +
> +	pr_debug("%s: vsk=%p send_request\n", __func__, vsk);
> +	return trans->ops->send_pkt(vsk, &info);
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_connect);
> +
> +int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +	struct virtio_vsock_pkt_info info = {
> +		.op = VIRTIO_VSOCK_OP_SHUTDOWN,
> +		.type = VIRTIO_VSOCK_TYPE_STREAM,
> +		.flags = (mode & RCV_SHUTDOWN ?
> +			  VIRTIO_VSOCK_SHUTDOWN_RCV : 0) |
> +			 (mode & SEND_SHUTDOWN ?
> +			  VIRTIO_VSOCK_SHUTDOWN_SEND : 0),
> +	};
> +
> +	pr_debug("%s: vsk=%p: send_shutdown\n", __func__, vsk);
> +	return trans->ops->send_pkt(vsk, &info);
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_shutdown);
> +
> +void virtio_transport_release(struct vsock_sock *vsk)
> +{
> +	struct sock *sk = &vsk->sk;
> +
> +	pr_debug("%s: vsk=%p\n", __func__, vsk);
> +
> +	/* Tell other side to terminate connection */
> +	if (sk->sk_type == SOCK_STREAM && sk->sk_state == SS_CONNECTED) {
> +		virtio_transport_shutdown(vsk, SHUTDOWN_MASK);
> +	}
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_release);
> +
> +int
> +virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
> +			       struct sockaddr_vm *remote_addr,
> +			       struct msghdr *msg,
> +			       size_t dgram_len)
> +{
> +	return -EOPNOTSUPP;
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_dgram_enqueue);
> +
> +ssize_t
> +virtio_transport_stream_enqueue(struct vsock_sock *vsk,
> +				struct msghdr *msg,
> +				size_t len)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +	struct virtio_vsock_pkt_info info = {
> +		.op = VIRTIO_VSOCK_OP_RW,
> +		.type = VIRTIO_VSOCK_TYPE_STREAM,
> +		.msg = msg,
> +		.pkt_len = len,
> +	};
> +
> +	return trans->ops->send_pkt(vsk, &info);
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_stream_enqueue);
> +
> +void virtio_transport_destruct(struct vsock_sock *vsk)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +
> +	pr_debug("%s: vsk=%p\n", __func__, vsk);
> +	kfree(trans);
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_destruct);
> +
> +static int virtio_transport_send_reset(struct vsock_sock *vsk,
> +				       struct virtio_vsock_pkt *pkt)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +	struct virtio_vsock_pkt_info info = {
> +		.op = VIRTIO_VSOCK_OP_RST,
> +		.type = VIRTIO_VSOCK_TYPE_STREAM,
> +	};
> +
> +	pr_debug("%s\n", __func__);
> +
> +	/* Send RST only if the original pkt is not a RST pkt */
> +	if (le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_RST)
> +		return 0;
> +
> +	return trans->ops->send_pkt(vsk, &info);
> +}
> +
> +static int
> +virtio_transport_recv_connecting(struct sock *sk,
> +				 struct virtio_vsock_pkt *pkt)
> +{
> +	struct vsock_sock *vsk = vsock_sk(sk);
> +	int err;
> +	int skerr;
> +
> +	pr_debug("%s: vsk=%p\n", __func__, vsk);
> +	switch (le16_to_cpu(pkt->hdr.op)) {
> +	case VIRTIO_VSOCK_OP_RESPONSE:
> +		pr_debug("%s: got RESPONSE\n", __func__);
> +		sk->sk_state = SS_CONNECTED;
> +		sk->sk_socket->state = SS_CONNECTED;
> +		vsock_insert_connected(vsk);
> +		sk->sk_state_change(sk);
> +		break;
> +	case VIRTIO_VSOCK_OP_INVALID:
> +		pr_debug("%s: got invalid\n", __func__);
> +		break;
> +	case VIRTIO_VSOCK_OP_RST:
> +		pr_debug("%s: got rst\n", __func__);
> +		skerr = ECONNRESET;
> +		err = 0;
> +		goto destroy;
> +	default:
> +		pr_debug("%s: got def\n", __func__);
> +		skerr = EPROTO;
> +		err = -EINVAL;
> +		goto destroy;
> +	}
> +	return 0;
> +
> +destroy:
> +	virtio_transport_send_reset(vsk, pkt);
> +	sk->sk_state = SS_UNCONNECTED;
> +	sk->sk_err = skerr;
> +	sk->sk_error_report(sk);
> +	return err;
> +}
> +
> +static int
> +virtio_transport_recv_connected(struct sock *sk,
> +				struct virtio_vsock_pkt *pkt)
> +{
> +	struct vsock_sock *vsk = vsock_sk(sk);
> +	struct virtio_transport *trans = vsk->trans;
> +	int err = 0;
> +
> +	switch (le16_to_cpu(pkt->hdr.op)) {
> +	case VIRTIO_VSOCK_OP_RW:
> +		pkt->len = le32_to_cpu(pkt->hdr.len);
> +		pkt->off = 0;
> +		pkt->trans = trans;
> +
> +		mutex_lock(&trans->rx_lock);
> +		virtio_transport_inc_rx_pkt(pkt);
> +		list_add_tail(&pkt->list, &trans->rx_queue);
> +		mutex_unlock(&trans->rx_lock);
> +
> +		sk->sk_data_ready(sk);
> +		return err;
> +	case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
> +		sk->sk_write_space(sk);
> +		break;
> +	case VIRTIO_VSOCK_OP_SHUTDOWN:
> +		pr_debug("%s: got shutdown\n", __func__);
> +		if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SHUTDOWN_RCV)
> +			vsk->peer_shutdown |= RCV_SHUTDOWN;
> +		if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SHUTDOWN_SEND)
> +			vsk->peer_shutdown |= SEND_SHUTDOWN;
> +		if (le32_to_cpu(pkt->hdr.flags))
> +			sk->sk_state_change(sk);
> +		break;
> +	case VIRTIO_VSOCK_OP_RST:
> +		pr_debug("%s: got rst\n", __func__);
> +		sock_set_flag(sk, SOCK_DONE);
> +		vsk->peer_shutdown = SHUTDOWN_MASK;
> +		if (vsock_stream_has_data(vsk) <= 0)
> +			sk->sk_state = SS_DISCONNECTING;
> +		sk->sk_state_change(sk);
> +		break;
> +	default:
> +		err = -EINVAL;
> +		break;
> +	}
> +
> +	virtio_transport_free_pkt(pkt);
> +	return err;
> +}
> +
> +static int
> +virtio_transport_send_response(struct vsock_sock *vsk,
> +			       struct virtio_vsock_pkt *pkt)
> +{
> +	struct virtio_transport *trans = vsk->trans;
> +	struct virtio_vsock_pkt_info info = {
> +		.op = VIRTIO_VSOCK_OP_RESPONSE,
> +		.type = VIRTIO_VSOCK_TYPE_STREAM,
> +		.remote_cid = le32_to_cpu(pkt->hdr.src_cid),
> +		.remote_port = le32_to_cpu(pkt->hdr.src_port),
> +	};
> +
> +	pr_debug("%s: send_response\n", __func__);
> +
> +	return trans->ops->send_pkt(vsk, &info);
> +}
> +
> +/* Handle server socket */
> +static int
> +virtio_transport_recv_listen(struct sock *sk, struct virtio_vsock_pkt *pkt)
> +{
> +	struct vsock_sock *vsk = vsock_sk(sk);
> +	struct vsock_sock *vchild;
> +	struct sock *child;
> +
> +	if (le16_to_cpu(pkt->hdr.op) != VIRTIO_VSOCK_OP_REQUEST) {
> +		virtio_transport_send_reset(vsk, pkt);
> +		return -EINVAL;
> +	}
> +
> +	if (sk_acceptq_is_full(sk)) {
> +		virtio_transport_send_reset(vsk, pkt);
> +		return -ENOMEM;
> +	}
> +
> +	pr_debug("%s: create pending\n", __func__);
> +	child = __vsock_create(sock_net(sk), NULL, sk, GFP_KERNEL,
> +			       sk->sk_type, 0);
> +	if (!child) {
> +		virtio_transport_send_reset(vsk, pkt);
> +		return -ENOMEM;
> +	}
> +
> +	sk->sk_ack_backlog++;
> +
> +	lock_sock(child);
> +
> +	child->sk_state = SS_CONNECTED;
> +
> +	vchild = vsock_sk(child);
> +	vsock_addr_init(&vchild->local_addr, le32_to_cpu(pkt->hdr.dst_cid),
> +			le32_to_cpu(pkt->hdr.dst_port));
> +	vsock_addr_init(&vchild->remote_addr, le32_to_cpu(pkt->hdr.src_cid),
> +			le32_to_cpu(pkt->hdr.src_port));
> +
> +	vsock_insert_connected(vchild);
> +	vsock_enqueue_accept(sk, child);
> +	virtio_transport_send_response(vchild, pkt);
> +
> +	release_sock(child);
> +
> +	sk->sk_data_ready(sk);
> +	return 0;
> +}
> +
> +static void virtio_transport_space_update(struct sock *sk,
> +					  struct virtio_vsock_pkt *pkt)
> +{
> +	struct vsock_sock *vsk = vsock_sk(sk);
> +	struct virtio_transport *trans = vsk->trans;
> +	bool space_available;
> +
> +	/* buf_alloc and fwd_cnt is always included in the hdr */
> +	mutex_lock(&trans->tx_lock);
> +	trans->peer_buf_alloc = le32_to_cpu(pkt->hdr.buf_alloc);
> +	trans->peer_fwd_cnt = le32_to_cpu(pkt->hdr.fwd_cnt);
> +	space_available = virtio_transport_has_space(vsk);
> +	mutex_unlock(&trans->tx_lock);
> +
> +	if (space_available)
> +		sk->sk_write_space(sk);
> +}
> +
> +/* We are under the virtio-vsock's vsock->rx_lock or
> + * vhost-vsock's vq->mutex lock */
> +void virtio_transport_recv_pkt(struct virtio_vsock_pkt *pkt)
> +{
> +	struct virtio_transport *trans;
> +	struct sockaddr_vm src, dst;
> +	struct vsock_sock *vsk;
> +	struct sock *sk;
> +
> +	vsock_addr_init(&src, le32_to_cpu(pkt->hdr.src_cid), le32_to_cpu(pkt->hdr.src_port));
> +	vsock_addr_init(&dst, le32_to_cpu(pkt->hdr.dst_cid), le32_to_cpu(pkt->hdr.dst_port));
> +
> +	virtio_vsock_dumppkt(__func__, pkt);
> +
> +	if (le16_to_cpu(pkt->hdr.type) != VIRTIO_VSOCK_TYPE_STREAM) {
> +		/* TODO send RST */

TODO's shouldn't make it into final submissions.

> +		goto free_pkt;
> +	}
> +
> +	/* The socket must be in connected or bound table
> +	 * otherwise send reset back
> +	 */
> +	sk = vsock_find_connected_socket(&src, &dst);
> +	if (!sk) {
> +		sk = vsock_find_bound_socket(&dst);
> +		if (!sk) {
> +			pr_debug("%s: can not find bound_socket\n", __func__);
> +			virtio_vsock_dumppkt(__func__, pkt);
> +			/* Ignore this pkt instead of sending reset back */
> +			/* TODO send a RST unless this packet is a RST
> (to avoid infinite loops) */

Ditto.

> +			goto free_pkt;
> +		}
> +	}
> +
> +	vsk = vsock_sk(sk);
> +	trans = vsk->trans;
> +	BUG_ON(!trans);

See above re: BUG_ON

> +
> +	virtio_transport_space_update(sk, pkt);
> +
> +	lock_sock(sk);
> +	switch (sk->sk_state) {
> +	case VSOCK_SS_LISTEN:
> +		virtio_transport_recv_listen(sk, pkt);
> +		virtio_transport_free_pkt(pkt);
> +		break;
> +	case SS_CONNECTING:
> +		virtio_transport_recv_connecting(sk, pkt);
> +		virtio_transport_free_pkt(pkt);
> +		break;
> +	case SS_CONNECTED:
> +		virtio_transport_recv_connected(sk, pkt);
> +		break;
> +	default:
> +		virtio_transport_free_pkt(pkt);
> +		break;
> +	}
> +	release_sock(sk);
> +
> +	/* Release refcnt obtained when we fetched this socket out of the
> +	 * bound or connected list.
> +	 */
> +	sock_put(sk);
> +	return;
> +
> +free_pkt:
> +	virtio_transport_free_pkt(pkt);
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_recv_pkt);
> +
> +void virtio_transport_free_pkt(struct virtio_vsock_pkt *pkt)
> +{
> +	kfree(pkt->buf);
> +	kfree(pkt);
> +}
> +EXPORT_SYMBOL_GPL(virtio_transport_free_pkt);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Asias He");
> +MODULE_DESCRIPTION("common code for virtio vsock");
> --
> 2.5.0

--
Alex Bennée
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