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Date:   Thu, 24 Nov 2022 16:27:41 +0100
From:   Stefano Garzarella <sgarzare@redhat.com>
To:     Arseniy Krasnov <oxffffaa@gmail.com>
Cc:     Bobby Eshleman <bobby.eshleman@bytedance.com>,
        Bobby Eshleman <bobbyeshleman@gmail.com>,
        Cong Wang <cong.wang@bytedance.com>,
        Jiang Wang <jiang.wang@bytedance.com>,
        Stefan Hajnoczi <stefanha@redhat.com>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, kvm@vger.kernel.org,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, AVKrasnov@sberdevices.ru
Subject: Re: [PATCH v4] virtio/vsock: replace virtio_vsock_pkt with sk_buff
Message-ID: <20221124152741.nalvcbkdfva5augp@sgarzare-redhat>
References: <20221124060750.48223-1-bobby.eshleman@bytedance.com>
 <16516161-d7c7-063c-c4eb-c2aca72878f6@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Disposition: inline
In-Reply-To: <16516161-d7c7-063c-c4eb-c2aca72878f6@gmail.com>
Precedence: bulk

On Thu, Nov 24, 2022 at 05:30:24PM +0300, Arseniy Krasnov wrote:
>Hello Bobby,
>
>On 24.11.2022 09:07, Bobby Eshleman wrote:
>> This commit changes virtio/vsock to use sk_buff instead of
>> virtio_vsock_pkt. Beyond better conforming to other net code, using
>> sk_buff allows vsock to use sk_buff-dependent features in the future
>> (such as sockmap) and improves throughput.
>>
>> This patch introduces the following performance changes:
>>
>> Tool/Config: uperf w/ 64 threads, SOCK_STREAM
>> Test Runs: 5, mean of results
>> Before: commit 95ec6bce2a0b ("Merge branch 'net-ipa-more-endpoints'")
>>
>> Test: 64KB, g2h
>> Before: 21.63 Gb/s
>> After: 25.59 Gb/s (+18%)
>>
>> Test: 16B, g2h
>> Before: 11.86 Mb/s
>> After: 17.41 Mb/s (+46%)
>>
>> Test: 64KB, h2g
>> Before: 2.15 Gb/s
>> After: 3.6 Gb/s (+67%)
>>
>> Test: 16B, h2g
>> Before: 14.38 Mb/s
>> After: 18.43 Mb/s (+28%)
>>
>> Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
>> ---
>> Changes in v4:
>> - vdso/bits.h -> linux/bits.h
>> - add virtio_vsock_alloc_skb() helper
>> - virtio/vsock: rename buf_len -> total_len
>> - update last_hdr->len
>> - fix build_skb() for vsockmon (tested)
>> - add queue helpers
>> - use spin_{unlock/lock}_bh() instead of spin_lock()/spin_unlock()
>>    - note: I only ran a few g2h tests to check that this change
>>      had no perf impact. The above data is still from patch
>>      v3.
>>
>> Changes in v3:
>> - fix seqpacket bug
>> - use zero in vhost_add_used(..., 0) device doesn't write to
>> buffer
>> - use xmas tree style declarations
>> - vsock_hdr() -> virtio_vsock_hdr() and other include file style fixes
>> - no skb merging
>> - save space by not using vsock_metadata
>>     - use _skb_refdst instead of skb buffer space for flags
>>     - use skb_pull() to keep track of read bytes instead of
>>       using an an extra variable 'off' in the skb buffer space
>> - remove unnecessary sk_allocation assignment
>> - do not zero hdr needlessly
>> - introduce virtio_transport_skb_len() because skb->len changes now
>> - use spin_lock() directly on queue lock instead of sk_buff_head helpers
>>   which use spin_lock_irqsave() (e.g., skb_dequeue)
>> - do not reduce buffer size to be page size divisible
>> - Note: the biggest performance change came from loosening the spinlock
>>   variation and not reducing the buffer size.
>>
>> Changes in v2:
>> - Use alloc_skb() directly instead of sock_alloc_send_pskb() to minimize
>>   uAPI changes.
>> - Do not marshal errors to -ENOMEM for non-virtio implementations.
>> - No longer a part of the original series
>> - Some code cleanup and refactoring
>> - Include performance stats
>>  drivers/vhost/vsock.c                   | 213 +++++-------
>>  include/linux/virtio_vsock.h            | 145 ++++++--
>>  net/vmw_vsock/virtio_transport.c        | 149 +++------
>>  net/vmw_vsock/virtio_transport_common.c | 422 +++++++++++++-----------
>>  net/vmw_vsock/vsock_loopback.c          |  51 +--
>>  5 files changed, 514 insertions(+), 466 deletions(-)
>>
>> diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
>> index 5703775af129..04b28c4c58d0 100644
>> --- a/drivers/vhost/vsock.c
>> +++ b/drivers/vhost/vsock.c
>> @@ -51,8 +51,7 @@ struct vhost_vsock {
>>  	struct hlist_node hash;
>>
>>  	struct vhost_work send_pkt_work;
>> -	spinlock_t send_pkt_list_lock;
>> -	struct list_head send_pkt_list;	/* host->guest pending packets */
>> +	struct sk_buff_head send_pkt_queue; /* host->guest pending packets */
>>
>>  	atomic_t queued_replies;
>>
>> @@ -108,40 +107,33 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
>>  	vhost_disable_notify(&vsock->dev, vq);
>>
>>  	do {
>> -		struct virtio_vsock_pkt *pkt;
>> +		struct virtio_vsock_hdr *hdr;
>> +		size_t iov_len, payload_len;
>>  		struct iov_iter iov_iter;
>> +		u32 flags_to_restore = 0;
>> +		struct sk_buff *skb;
>>  		unsigned out, in;
>>  		size_t nbytes;
>> -		size_t iov_len, payload_len;
>>  		int head;
>> -		u32 flags_to_restore = 0;
>>
>> -		spin_lock_bh(&vsock->send_pkt_list_lock);
>> -		if (list_empty(&vsock->send_pkt_list)) {
>> -			spin_unlock_bh(&vsock->send_pkt_list_lock);
>> +		spin_lock(&vsock->send_pkt_queue.lock);
>> +		skb = __skb_dequeue(&vsock->send_pkt_queue);
>> +		spin_unlock(&vsock->send_pkt_queue.lock);
>> +
>> +		if (!skb) {
>>  			vhost_enable_notify(&vsock->dev, vq);
>>  			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);
>> -
>>  		head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
>>  					 &out, &in, NULL, NULL);
>>  		if (head < 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);
>> +			virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);
>>  			break;
>>  		}
>>
>>  		if (head == vq->num) {
>> -			spin_lock_bh(&vsock->send_pkt_list_lock);
>> -			list_add(&pkt->list, &vsock->send_pkt_list);
>> -			spin_unlock_bh(&vsock->send_pkt_list_lock);
>> -
>> +			virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);
>>  			/* We cannot finish yet if more buffers snuck in while
>>  			 * re-enabling notify.
>>  			 */
>> @@ -153,26 +145,27 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
>>  		}
>>
>>  		if (out) {
>> -			virtio_transport_free_pkt(pkt);
>> +			virtio_vsock_kfree_skb(skb);
>>  			vq_err(vq, "Expected 0 output buffers, got %u\n", out);
>>  			break;
>>  		}
>>
>>  		iov_len = iov_length(&vq->iov[out], in);
>> -		if (iov_len < sizeof(pkt->hdr)) {
>> -			virtio_transport_free_pkt(pkt);
>> +		if (iov_len < sizeof(*hdr)) {
>> +			virtio_vsock_kfree_skb(skb);
>>  			vq_err(vq, "Buffer len [%zu] too small\n", iov_len);
>>  			break;
>>  		}
>>
>>  		iov_iter_init(&iov_iter, READ, &vq->iov[out], in, iov_len);
>> -		payload_len = pkt->len - pkt->off;
>> +		payload_len = skb->len;
>> +		hdr = virtio_vsock_hdr(skb);
>>
>>  		/* If the packet is greater than the space available in the
>>  		 * buffer, we split it using multiple buffers.
>>  		 */
>> -		if (payload_len > iov_len - sizeof(pkt->hdr)) {
>> -			payload_len = iov_len - sizeof(pkt->hdr);
>> +		if (payload_len > iov_len - sizeof(*hdr)) {
>> +			payload_len = iov_len - sizeof(*hdr);
>>
>>  			/* As we are copying pieces of large packet's buffer to
>>  			 * small rx buffers, headers of packets in rx queue are
>> @@ -185,31 +178,30 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
>>  			 * bits set. After initialized header will be copied to
>>  			 * rx buffer, these required bits will be restored.
>>  			 */
>> -			if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOM) {
>> -				pkt->hdr.flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
>> +			if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM) {
>> +				hdr->flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
>>  				flags_to_restore |= VIRTIO_VSOCK_SEQ_EOM;
>>
>> -				if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOR) {
>> -					pkt->hdr.flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
>> +				if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOR) {
>> +					hdr->flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
>>  					flags_to_restore |= VIRTIO_VSOCK_SEQ_EOR;
>>  				}
>>  			}
>>  		}
>>
>>  		/* Set the correct length in the header */
>> -		pkt->hdr.len = cpu_to_le32(payload_len);
>> +		hdr->len = cpu_to_le32(payload_len);
>>
>> -		nbytes = copy_to_iter(&pkt->hdr, sizeof(pkt->hdr), &iov_iter);
>> -		if (nbytes != sizeof(pkt->hdr)) {
>> -			virtio_transport_free_pkt(pkt);
>> +		nbytes = copy_to_iter(hdr, sizeof(*hdr), &iov_iter);
>> +		if (nbytes != sizeof(*hdr)) {
>> +			virtio_vsock_kfree_skb(skb);
>>  			vq_err(vq, "Faulted on copying pkt hdr\n");
>>  			break;
>>  		}
>>
>> -		nbytes = copy_to_iter(pkt->buf + pkt->off, payload_len,
>> -				      &iov_iter);
>> +		nbytes = copy_to_iter(skb->data, payload_len, &iov_iter);
>>  		if (nbytes != payload_len) {
>> -			virtio_transport_free_pkt(pkt);
>> +			virtio_vsock_kfree_skb(skb);
>>  			vq_err(vq, "Faulted on copying pkt buf\n");
>>  			break;
>>  		}
>> @@ -217,31 +209,28 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
>>  		/* Deliver to monitoring devices all packets that we
>>  		 * will transmit.
>>  		 */
>> -		virtio_transport_deliver_tap_pkt(pkt);
>> +		virtio_transport_deliver_tap_pkt(skb);
>>
>> -		vhost_add_used(vq, head, sizeof(pkt->hdr) + payload_len);
>> +		vhost_add_used(vq, head, sizeof(*hdr) + payload_len);
>>  		added = true;
>>
>> -		pkt->off += payload_len;
>> +		skb_pull(skb, payload_len);
>>  		total_len += payload_len;
>>
>>  		/* If we didn't send all the payload we can requeue the packet
>>  		 * to send it with the next available buffer.
>>  		 */
>> -		if (pkt->off < pkt->len) {
>> -			pkt->hdr.flags |= cpu_to_le32(flags_to_restore);
>> +		if (skb->len > 0) {
>> +			hdr->flags |= cpu_to_le32(flags_to_restore);
>>
>> -			/* We are queueing the same virtio_vsock_pkt to handle
>> +			/* We are queueing the same skb to handle
>>  			 * the remaining bytes, and we want to deliver it
>>  			 * to monitoring devices in the next iteration.
>>  			 */
>> -			pkt->tap_delivered = false;
>> -
>> -			spin_lock_bh(&vsock->send_pkt_list_lock);
>> -			list_add(&pkt->list, &vsock->send_pkt_list);
>> -			spin_unlock_bh(&vsock->send_pkt_list_lock);
>> +			virtio_vsock_skb_clear_tap_delivered(skb);
>> +			virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);
>>  		} else {
>> -			if (pkt->reply) {
>> +			if (virtio_vsock_skb_reply(skb)) {
>>  				int val;
>>
>>  				val = atomic_dec_return(&vsock->queued_replies);
>> @@ -253,7 +242,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
>>  					restart_tx = true;
>>  			}
>>
>> -			virtio_transport_free_pkt(pkt);
>> +			virtio_vsock_consume_skb(skb);
>>  		}
>>  	} while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
>>  	if (added)
>> @@ -278,28 +267,26 @@ static void vhost_transport_send_pkt_work(struct vhost_work *work)
>>  }
>>
>>  static int
>> -vhost_transport_send_pkt(struct virtio_vsock_pkt *pkt)
>> +vhost_transport_send_pkt(struct sk_buff *skb)
>>  {
>> +	struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
>>  	struct vhost_vsock *vsock;
>> -	int len = pkt->len;
>> +	int len = skb->len;
>>
>>  	rcu_read_lock();
>>
>>  	/* Find the vhost_vsock according to guest context id  */
>> -	vsock = vhost_vsock_get(le64_to_cpu(pkt->hdr.dst_cid));
>> +	vsock = vhost_vsock_get(le64_to_cpu(hdr->dst_cid));
>>  	if (!vsock) {
>>  		rcu_read_unlock();
>> -		virtio_transport_free_pkt(pkt);
>> +		virtio_vsock_kfree_skb(skb);
>>  		return -ENODEV;
>>  	}
>>
>> -	if (pkt->reply)
>> +	if (virtio_vsock_skb_reply(skb))
>>  		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);
>> -
>> +	virtio_vsock_skb_queue_tail(&vsock->send_pkt_queue, skb);
>>  	vhost_work_queue(&vsock->dev, &vsock->send_pkt_work);
>>
>>  	rcu_read_unlock();
>> @@ -310,10 +297,8 @@ static int
>>  vhost_transport_cancel_pkt(struct vsock_sock *vsk)
>>  {
>>  	struct vhost_vsock *vsock;
>> -	struct virtio_vsock_pkt *pkt, *n;
>>  	int cnt = 0;
>>  	int ret = -ENODEV;
>> -	LIST_HEAD(freeme);
>>
>>  	rcu_read_lock();
>>
>> @@ -322,20 +307,7 @@ vhost_transport_cancel_pkt(struct vsock_sock *vsk)
>>  	if (!vsock)
>>  		goto out;
>>
>> -	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);
>> -	}
>> +	cnt = virtio_transport_purge_skbs(vsk, &vsock->send_pkt_queue);
>>
>>  	if (cnt) {
>>  		struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX];
>> @@ -352,12 +324,14 @@ vhost_transport_cancel_pkt(struct vsock_sock *vsk)
>>  	return ret;
>>  }
>>
>> -static struct virtio_vsock_pkt *
>> -vhost_vsock_alloc_pkt(struct vhost_virtqueue *vq,
>> +static struct sk_buff *
>> +vhost_vsock_alloc_skb(struct vhost_virtqueue *vq,
>>  		      unsigned int out, unsigned int in)
>>  {
>> -	struct virtio_vsock_pkt *pkt;
>> +	struct virtio_vsock_hdr *hdr;
>>  	struct iov_iter iov_iter;
>> +	struct sk_buff *skb;
>> +	size_t payload_len;
>>  	size_t nbytes;
>>  	size_t len;
>>
>> @@ -366,50 +340,47 @@ vhost_vsock_alloc_pkt(struct vhost_virtqueue *vq,
>>  		return NULL;
>>  	}
>>
>> -	pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
>> -	if (!pkt)
>> +	len = iov_length(vq->iov, out);
>> +
>> +	/* len contains both payload and hdr */
>> +	skb = virtio_vsock_alloc_skb(len, GFP_KERNEL);
>> +	if (!skb)
>>  		return NULL;
>>
>> -	len = iov_length(vq->iov, out);
>>  	iov_iter_init(&iov_iter, WRITE, vq->iov, out, len);
>>
>> -	nbytes = copy_from_iter(&pkt->hdr, sizeof(pkt->hdr), &iov_iter);
>> -	if (nbytes != sizeof(pkt->hdr)) {
>> +	hdr = virtio_vsock_hdr(skb);
>> +	nbytes = copy_from_iter(hdr, sizeof(*hdr), &iov_iter);
>> +	if (nbytes != sizeof(*hdr)) {
>>  		vq_err(vq, "Expected %zu bytes for pkt->hdr, got %zu bytes\n",
>> -		       sizeof(pkt->hdr), nbytes);
>> -		kfree(pkt);
>> +		       sizeof(*hdr), nbytes);
>> +		virtio_vsock_kfree_skb(skb);
>>  		return NULL;
>>  	}
>>
>> -	pkt->len = le32_to_cpu(pkt->hdr.len);
>> +	payload_len = le32_to_cpu(hdr->len);
>>
>>  	/* No payload */
>> -	if (!pkt->len)
>> -		return pkt;
>> +	if (!payload_len)
>> +		return skb;
>>
>>  	/* The pkt is too big */
>> -	if (pkt->len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE) {
>> -		kfree(pkt);
>> +	if (payload_len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE) {
>> +		virtio_vsock_kfree_skb(skb);
>>  		return NULL;
>>  	}
>>
>> -	pkt->buf = kvmalloc(pkt->len, GFP_KERNEL);
>> -	if (!pkt->buf) {
>> -		kfree(pkt);
>> -		return NULL;
>> -	}
>> +	virtio_vsock_skb_rx_put(skb);
>>
>> -	pkt->buf_len = pkt->len;
>> -
>> -	nbytes = copy_from_iter(pkt->buf, pkt->len, &iov_iter);
>> -	if (nbytes != pkt->len) {
>> -		vq_err(vq, "Expected %u byte payload, got %zu bytes\n",
>> -		       pkt->len, nbytes);
>> -		virtio_transport_free_pkt(pkt);
>> +	nbytes = copy_from_iter(skb->data, payload_len, &iov_iter);
>> +	if (nbytes != payload_len) {
>> +		vq_err(vq, "Expected %zu byte payload, got %zu bytes\n",
>> +		       payload_len, nbytes);
>> +		virtio_vsock_kfree_skb(skb);
>>  		return NULL;
>>  	}
>>
>> -	return pkt;
>> +	return skb;
>>  }
>>
>>  /* Is there space left for replies to rx packets? */
>> @@ -496,9 +467,9 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
>>  						  poll.work);
>>  	struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
>>  						 dev);
>> -	struct virtio_vsock_pkt *pkt;
>>  	int head, pkts = 0, total_len = 0;
>>  	unsigned int out, in;
>> +	struct sk_buff *skb;
>>  	bool added = false;
>>
>>  	mutex_lock(&vq->mutex);
>> @@ -511,6 +482,8 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
>>
>>  	vhost_disable_notify(&vsock->dev, vq);
>>  	do {
>> +		struct virtio_vsock_hdr *hdr;
>> +
>>  		if (!vhost_vsock_more_replies(vsock)) {
>>  			/* Stop tx until the device processes already
>>  			 * pending replies.  Leave tx virtqueue
>> @@ -532,24 +505,26 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
>>  			break;
>>  		}
>>
>> -		pkt = vhost_vsock_alloc_pkt(vq, out, in);
>> -		if (!pkt) {
>> +		skb = vhost_vsock_alloc_skb(vq, out, in);
>> +		if (!skb) {
>>  			vq_err(vq, "Faulted on pkt\n");
>>  			continue;
>>  		}
>>
>> -		total_len += sizeof(pkt->hdr) + pkt->len;
>> +		total_len += sizeof(*hdr) + skb->len;
>>
>>  		/* Deliver to monitoring devices all received packets */
>> -		virtio_transport_deliver_tap_pkt(pkt);
>> +		virtio_transport_deliver_tap_pkt(skb);
>> +
>> +		hdr = virtio_vsock_hdr(skb);
>>
>>  		/* Only accept correctly addressed packets */
>> -		if (le64_to_cpu(pkt->hdr.src_cid) == vsock->guest_cid &&
>> -		    le64_to_cpu(pkt->hdr.dst_cid) ==
>> +		if (le64_to_cpu(hdr->src_cid) == vsock->guest_cid &&
>> +		    le64_to_cpu(hdr->dst_cid) ==
>>  		    vhost_transport_get_local_cid())
>> -			virtio_transport_recv_pkt(&vhost_transport, pkt);
>> +			virtio_transport_recv_pkt(&vhost_transport, skb);
>>  		else
>> -			virtio_transport_free_pkt(pkt);
>> +			virtio_vsock_kfree_skb(skb);
>>
>>  		vhost_add_used(vq, head, 0);
>>  		added = true;
>> @@ -693,8 +668,7 @@ static int vhost_vsock_dev_open(struct inode *inode, struct file *file)
>>  		       VHOST_VSOCK_WEIGHT, true, NULL);
>>
>>  	file->private_data = vsock;
>> -	spin_lock_init(&vsock->send_pkt_list_lock);
>> -	INIT_LIST_HEAD(&vsock->send_pkt_list);
>> +	skb_queue_head_init(&vsock->send_pkt_queue);
>>  	vhost_work_init(&vsock->send_pkt_work, vhost_transport_send_pkt_work);
>>  	return 0;
>>
>> @@ -760,16 +734,7 @@ static int vhost_vsock_dev_release(struct inode *inode, struct file *file)
>>  	vhost_vsock_flush(vsock);
>>  	vhost_dev_stop(&vsock->dev);
>>
>> -	spin_lock_bh(&vsock->send_pkt_list_lock);
>> -	while (!list_empty(&vsock->send_pkt_list)) {
>> -		struct virtio_vsock_pkt *pkt;
>> -
>> -		pkt = list_first_entry(&vsock->send_pkt_list,
>> -				struct virtio_vsock_pkt, list);
>> -		list_del_init(&pkt->list);
>> -		virtio_transport_free_pkt(pkt);
>> -	}
>> -	spin_unlock_bh(&vsock->send_pkt_list_lock);
>> +	virtio_vsock_skb_queue_purge(&vsock->send_pkt_queue);
>>
>>  	vhost_dev_cleanup(&vsock->dev);
>>  	kfree(vsock->dev.vqs);
>> diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>> index 35d7eedb5e8e..6c0b2d4da3fe 100644
>> --- a/include/linux/virtio_vsock.h
>> +++ b/include/linux/virtio_vsock.h
>> @@ -3,10 +3,129 @@
>>  #define _LINUX_VIRTIO_VSOCK_H
>>
>>  #include <uapi/linux/virtio_vsock.h>
>> +#include <linux/bits.h>
>>  #include <linux/socket.h>
>>  #include <net/sock.h>
>>  #include <net/af_vsock.h>
>>
>> +#define VIRTIO_VSOCK_SKB_HEADROOM (sizeof(struct virtio_vsock_hdr))
>> +
>> +enum virtio_vsock_skb_flags {
>> +	VIRTIO_VSOCK_SKB_FLAGS_REPLY		= BIT(0),
>> +	VIRTIO_VSOCK_SKB_FLAGS_TAP_DELIVERED	= BIT(1),
>> +};
>> +
>> +static inline struct virtio_vsock_hdr *virtio_vsock_hdr(struct sk_buff *skb)
>> +{
>> +	return (struct virtio_vsock_hdr *)skb->head;
>> +}
>> +
>> +static inline bool virtio_vsock_skb_reply(struct sk_buff *skb)
>> +{
>> +	return skb->_skb_refdst & VIRTIO_VSOCK_SKB_FLAGS_REPLY;
>> +}
>> +
>> +static inline void virtio_vsock_skb_set_reply(struct sk_buff *skb)
>> +{
>> +	skb->_skb_refdst |= VIRTIO_VSOCK_SKB_FLAGS_REPLY;
>> +}
>> +
>> +static inline bool virtio_vsock_skb_tap_delivered(struct sk_buff *skb)
>> +{
>> +	return skb->_skb_refdst & VIRTIO_VSOCK_SKB_FLAGS_TAP_DELIVERED;
>> +}
>> +
>> +static inline void virtio_vsock_skb_set_tap_delivered(struct sk_buff *skb)
>> +{
>> +	skb->_skb_refdst |= VIRTIO_VSOCK_SKB_FLAGS_TAP_DELIVERED;
>> +}
>> +
>> +static inline void virtio_vsock_skb_clear_tap_delivered(struct sk_buff *skb)
>> +{
>> +	skb->_skb_refdst &= ~VIRTIO_VSOCK_SKB_FLAGS_TAP_DELIVERED;
>> +}
>> +
>> +static inline void virtio_vsock_skb_rx_put(struct sk_buff *skb)
>> +{
>> +	u32 len;
>> +
>> +	len = le32_to_cpu(virtio_vsock_hdr(skb)->len);
>> +
>> +	if (len > 0)
>> +		skb_put(skb, len);
>> +}
>> +
>> +static inline struct sk_buff *virtio_vsock_alloc_skb(unsigned int size, gfp_t mask)
>> +{
>> +	struct sk_buff *skb;
>> +
>> +	skb = alloc_skb(size, mask);
>> +	if (!skb)
>> +		return NULL;
>> +
>> +	skb_reserve(skb, VIRTIO_VSOCK_SKB_HEADROOM);
>> +	return skb;
>> +}
>> +
>> +static inline void virtio_vsock_kfree_skb(struct sk_buff *skb)
>> +{
>> +	skb->_skb_refdst = 0;
>> +	kfree_skb(skb);
>> +}
>> +
>> +static inline void
>> +virtio_vsock_skb_queue_head(struct sk_buff_head *list, struct sk_buff *skb)
>> +{
>> +	spin_lock_bh(&list->lock);
>> +	__skb_queue_head(list, skb);
>> +	spin_unlock_bh(&list->lock);
>> +}
>> +
>> +static inline void
>> +virtio_vsock_skb_queue_tail(struct sk_buff_head *list, struct sk_buff *skb)
>> +{
>> +	spin_lock_bh(&list->lock);
>> +	__skb_queue_tail(list, skb);
>> +	spin_unlock_bh(&list->lock);
>> +}
>> +
>> +static inline struct sk_buff *virtio_vsock_skb_dequeue(struct sk_buff_head *list)
>> +{
>> +	struct sk_buff *skb;
>> +
>> +	spin_lock_bh(&list->lock);
>> +	skb = __skb_dequeue(list);
>> +	spin_unlock_bh(&list->lock);
>> +
>> +	return skb;
>> +}
>> +
>> +static inline void __virtio_vsock_skb_queue_purge(struct sk_buff_head *list)
>> +{
>> +	struct sk_buff *skb;
>> +
>> +	while ((skb = __skb_dequeue(list)) != NULL)
>> +		virtio_vsock_kfree_skb(skb);
>> +}
>> +
>> +static inline void virtio_vsock_skb_queue_purge(struct sk_buff_head *list)
>> +{
>> +	spin_lock_bh(&list->lock);
>> +	__virtio_vsock_skb_queue_purge(list);
>> +	spin_unlock_bh(&list->lock);
>> +}
>> +
>> +static inline size_t virtio_vsock_skb_len(struct sk_buff *skb)
>> +{
>> +	return (size_t)(skb_end_pointer(skb) - skb->head);
>> +}
>> +
>> +static inline void virtio_vsock_consume_skb(struct sk_buff *skb)
>> +{
>> +	skb->_skb_refdst = 0;
>> +	consume_skb(skb);
>> +}
>> +
>>  #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)
>> @@ -35,23 +154,10 @@ struct virtio_vsock_sock {
>>  	u32 last_fwd_cnt;
>>  	u32 rx_bytes;
>>  	u32 buf_alloc;
>> -	struct list_head rx_queue;
>> +	struct sk_buff_head rx_queue;
>>  	u32 msg_count;
>>  };
>>
>> -struct virtio_vsock_pkt {
>> -	struct virtio_vsock_hdr	hdr;
>> -	struct list_head list;
>> -	/* socket refcnt not held, only use for cancellation */
>> -	struct vsock_sock *vsk;
>> -	void *buf;
>> -	u32 buf_len;
>> -	u32 len;
>> -	u32 off;
>> -	bool reply;
>> -	bool tap_delivered;
>> -};
>> -
>>  struct virtio_vsock_pkt_info {
>>  	u32 remote_cid, remote_port;
>>  	struct vsock_sock *vsk;
>> @@ -68,7 +174,7 @@ struct virtio_transport {
>>  	struct vsock_transport transport;
>>
>>  	/* Takes ownership of the packet */
>> -	int (*send_pkt)(struct virtio_vsock_pkt *pkt);
>> +	int (*send_pkt)(struct sk_buff *skb);
>>  };
>>
>>  ssize_t
>> @@ -149,11 +255,10 @@ virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
>>  void virtio_transport_destruct(struct vsock_sock *vsk);
>>
>>  void virtio_transport_recv_pkt(struct virtio_transport *t,
>> -			       struct virtio_vsock_pkt *pkt);
>> -void virtio_transport_free_pkt(struct virtio_vsock_pkt *pkt);
>> -void virtio_transport_inc_tx_pkt(struct virtio_vsock_sock *vvs, struct virtio_vsock_pkt *pkt);
>> +			       struct sk_buff *skb);
>> +void virtio_transport_inc_tx_pkt(struct virtio_vsock_sock *vvs, struct sk_buff *skb);
>>  u32 virtio_transport_get_credit(struct virtio_vsock_sock *vvs, u32 wanted);
>>  void virtio_transport_put_credit(struct virtio_vsock_sock *vvs, u32 credit);
>> -void virtio_transport_deliver_tap_pkt(struct virtio_vsock_pkt *pkt);
>> -
>> +void virtio_transport_deliver_tap_pkt(struct sk_buff *skb);
>> +int virtio_transport_purge_skbs(void *vsk, struct sk_buff_head *list);
>>  #endif /* _LINUX_VIRTIO_VSOCK_H */
>> diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
>> index ad64f403536a..ee0c3c91c06b 100644
>> --- a/net/vmw_vsock/virtio_transport.c
>> +++ b/net/vmw_vsock/virtio_transport.c
>> @@ -42,8 +42,7 @@ struct virtio_vsock {
>>  	bool tx_run;
>>
>>  	struct work_struct send_pkt_work;
>> -	spinlock_t send_pkt_list_lock;
>> -	struct list_head send_pkt_list;
>> +	struct sk_buff_head send_pkt_queue;
>>
>>  	atomic_t queued_replies;
>>
>> @@ -101,41 +100,31 @@ virtio_transport_send_pkt_work(struct work_struct *work)
>>  	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;
>> +		struct sk_buff *skb;
>>  		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);
>> +		skb = virtio_vsock_skb_dequeue(&vsock->send_pkt_queue);
>> +		if (!skb)
>>  			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);
>> +		virtio_transport_deliver_tap_pkt(skb);
>> +		reply = virtio_vsock_skb_reply(skb);
>>
>> -		reply = pkt->reply;
>> -
>> -		sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
>> +		sg_init_one(&hdr, virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb)));
>>  		sgs[out_sg++] = &hdr;
>> -		if (pkt->buf) {
>> -			sg_init_one(&buf, pkt->buf, pkt->len);
>> +		if (skb->len > 0) {
>> +			sg_init_one(&buf, skb->data, skb->len);
>>  			sgs[out_sg++] = &buf;
>>  		}
>>
>> -		ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, pkt, GFP_KERNEL);
>> +		ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, 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);
>> +			virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);
>>  			break;
>>  		}
>>
>> @@ -164,32 +153,32 @@ virtio_transport_send_pkt_work(struct work_struct *work)
>>  }
>>
>>  static int
>> -virtio_transport_send_pkt(struct virtio_vsock_pkt *pkt)
>> +virtio_transport_send_pkt(struct sk_buff *skb)
>>  {
>> +	struct virtio_vsock_hdr *hdr;
>>  	struct virtio_vsock *vsock;
>> -	int len = pkt->len;
>> +	int len = skb->len;
>> +
>> +	hdr = virtio_vsock_hdr(skb);
>>
>>  	rcu_read_lock();
>>  	vsock = rcu_dereference(the_virtio_vsock);
>>  	if (!vsock) {
>> -		virtio_transport_free_pkt(pkt);
>> +		virtio_vsock_kfree_skb(skb);
>>  		len = -ENODEV;
>>  		goto out_rcu;
>>  	}
>>
>> -	if (le64_to_cpu(pkt->hdr.dst_cid) == vsock->guest_cid) {
>> -		virtio_transport_free_pkt(pkt);
>> +	if (le64_to_cpu(hdr->dst_cid) == vsock->guest_cid) {
>> +		virtio_vsock_kfree_skb(skb);
>>  		len = -ENODEV;
>>  		goto out_rcu;
>>  	}
>>
>> -	if (pkt->reply)
>> +	if (virtio_vsock_skb_reply(skb))
>>  		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);
>> -
>> +	virtio_vsock_skb_queue_tail(&vsock->send_pkt_queue, skb);
>>  	queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
>>
>>  out_rcu:
>> @@ -201,9 +190,7 @@ static int
>>  virtio_transport_cancel_pkt(struct vsock_sock *vsk)
>>  {
>>  	struct virtio_vsock *vsock;
>> -	struct virtio_vsock_pkt *pkt, *n;
>>  	int cnt = 0, ret;
>> -	LIST_HEAD(freeme);
>>
>>  	rcu_read_lock();
>>  	vsock = rcu_dereference(the_virtio_vsock);
>> @@ -212,20 +199,7 @@ virtio_transport_cancel_pkt(struct vsock_sock *vsk)
>>  		goto out_rcu;
>>  	}
>>
>> -	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);
>> -	}
>> +	cnt = virtio_transport_purge_skbs(vsk, &vsock->send_pkt_queue);
>>
>>  	if (cnt) {
>>  		struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
>> @@ -246,38 +220,28 @@ virtio_transport_cancel_pkt(struct vsock_sock *vsk)
>>
>>  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];
>> +	int total_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE + VIRTIO_VSOCK_SKB_HEADROOM;
>> +	struct scatterlist pkt, *p;
>>  	struct virtqueue *vq;
>> +	struct sk_buff *skb;
>>  	int ret;
>>
>>  	vq = vsock->vqs[VSOCK_VQ_RX];
>>
>>  	do {
>> -		pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
>> -		if (!pkt)
>> +		skb = virtio_vsock_alloc_skb(total_len, GFP_KERNEL);
>> +		if (!skb)
>>  			break;
>>
>> -		pkt->buf = kmalloc(buf_len, GFP_KERNEL);
>> -		if (!pkt->buf) {
>> -			virtio_transport_free_pkt(pkt);
>> +		memset(skb->head, 0, VIRTIO_VSOCK_SKB_HEADROOM);
>> +		sg_init_one(&pkt, virtio_vsock_hdr(skb), total_len);
>> +		p = &pkt;
>> +		ret = virtqueue_add_sgs(vq, &p, 0, 1, skb, GFP_KERNEL);
>> +		if (ret < 0) {
>> +			virtio_vsock_kfree_skb(skb);
>>  			break;
>>  		}
>>
>> -		pkt->buf_len = buf_len;
>> -		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)
>> @@ -299,12 +263,12 @@ static void virtio_transport_tx_work(struct work_struct *work)
>>  		goto out;
>>
>>  	do {
>> -		struct virtio_vsock_pkt *pkt;
>> +		struct sk_buff *skb;
>>  		unsigned int len;
>>
>>  		virtqueue_disable_cb(vq);
>> -		while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
>> -			virtio_transport_free_pkt(pkt);
>> +		while ((skb = virtqueue_get_buf(vq, &len)) != NULL) {
>> +			virtio_vsock_consume_skb(skb);
>>  			added = true;
>>  		}
>>  	} while (!virtqueue_enable_cb(vq));
>> @@ -529,7 +493,7 @@ static void virtio_transport_rx_work(struct work_struct *work)
>>  	do {
>>  		virtqueue_disable_cb(vq);
>>  		for (;;) {
>> -			struct virtio_vsock_pkt *pkt;
>> +			struct sk_buff *skb;
>>  			unsigned int len;
>>
>>  			if (!virtio_transport_more_replies(vsock)) {
>> @@ -540,23 +504,22 @@ static void virtio_transport_rx_work(struct work_struct *work)
>>  				goto out;
>>  			}
>>
>> -			pkt = virtqueue_get_buf(vq, &len);
>> -			if (!pkt) {
>> +			skb = virtqueue_get_buf(vq, &len);
>> +			if (!skb)
>>  				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);
>> +			if (unlikely(len < sizeof(struct virtio_vsock_hdr) ||
>> +				     len > virtio_vsock_skb_len(skb))) {
>> +				virtio_vsock_kfree_skb(skb);
>>  				continue;
>>  			}
>>
>> -			pkt->len = len - sizeof(pkt->hdr);
>> -			virtio_transport_deliver_tap_pkt(pkt);
>> -			virtio_transport_recv_pkt(&virtio_transport, pkt);
>> +			virtio_vsock_skb_rx_put(skb);
>> +			virtio_transport_deliver_tap_pkt(skb);
>> +			virtio_transport_recv_pkt(&virtio_transport, skb);
>>  		}
>>  	} while (!virtqueue_enable_cb(vq));
>>
>> @@ -610,7 +573,7 @@ static int virtio_vsock_vqs_init(struct virtio_vsock *vsock)
>>  static void virtio_vsock_vqs_del(struct virtio_vsock *vsock)
>>  {
>>  	struct virtio_device *vdev = vsock->vdev;
>> -	struct virtio_vsock_pkt *pkt;
>> +	struct sk_buff *skb;
>>
>>  	/* Reset all connected sockets when the VQs disappear */
>>  	vsock_for_each_connected_socket(&virtio_transport.transport,
>> @@ -637,23 +600,16 @@ static void virtio_vsock_vqs_del(struct virtio_vsock *vsock)
>>  	virtio_reset_device(vdev);
>>
>>  	mutex_lock(&vsock->rx_lock);
>> -	while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))
>> -		virtio_transport_free_pkt(pkt);
>> +	while ((skb = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))
>> +		virtio_vsock_kfree_skb(skb);
>>  	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);
>> +	while ((skb = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX])))
>> +		virtio_vsock_kfree_skb(skb);
>>  	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);
>> +	virtio_vsock_skb_queue_purge(&vsock->send_pkt_queue);
>>
>>  	/* Delete virtqueues and flush outstanding callbacks if any */
>>  	vdev->config->del_vqs(vdev);
>> @@ -690,8 +646,7 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
>>  	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);
>> +	skb_queue_head_init(&vsock->send_pkt_queue);
>>  	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);
>> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>> index a9980e9b9304..e3471653e051 100644
>> --- a/net/vmw_vsock/virtio_transport_common.c
>> +++ b/net/vmw_vsock/virtio_transport_common.c
>> @@ -37,53 +37,56 @@ virtio_transport_get_ops(struct vsock_sock *vsk)
>>  	return container_of(t, struct virtio_transport, transport);
>>  }
>>
>> -static struct virtio_vsock_pkt *
>> -virtio_transport_alloc_pkt(struct virtio_vsock_pkt_info *info,
>> +/* Returns a new packet on success, otherwise returns NULL.
>> + *
>> + * If NULL is returned, errp is set to a negative errno.
>> + */
>> +static struct sk_buff *
>> +virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
>>  			   size_t len,
>>  			   u32 src_cid,
>>  			   u32 src_port,
>>  			   u32 dst_cid,
>>  			   u32 dst_port)
>>  {
>> -	struct virtio_vsock_pkt *pkt;
>> +	const size_t skb_len = VIRTIO_VSOCK_SKB_HEADROOM + len;
>> +	struct virtio_vsock_hdr *hdr;
>> +	struct sk_buff *skb;
>> +	void *payload;
>>  	int err;
>>
>> -	pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
>> -	if (!pkt)
>> +	skb = virtio_vsock_alloc_skb(skb_len, GFP_KERNEL);
>> +	if (!skb)
>>  		return NULL;
>>
>> -	pkt->hdr.type		= cpu_to_le16(info->type);
>> -	pkt->hdr.op		= cpu_to_le16(info->op);
>> -	pkt->hdr.src_cid	= cpu_to_le64(src_cid);
>> -	pkt->hdr.dst_cid	= cpu_to_le64(dst_cid);
>> -	pkt->hdr.src_port	= cpu_to_le32(src_port);
>> -	pkt->hdr.dst_port	= cpu_to_le32(dst_port);
>> -	pkt->hdr.flags		= cpu_to_le32(info->flags);
>> -	pkt->len		= len;
>> -	pkt->hdr.len		= cpu_to_le32(len);
>> -	pkt->reply		= info->reply;
>> -	pkt->vsk		= info->vsk;
>> +	hdr = virtio_vsock_hdr(skb);
>> +	hdr->type	= cpu_to_le16(info->type);
>> +	hdr->op		= cpu_to_le16(info->op);
>> +	hdr->src_cid	= cpu_to_le64(src_cid);
>> +	hdr->dst_cid	= cpu_to_le64(dst_cid);
>> +	hdr->src_port	= cpu_to_le32(src_port);
>> +	hdr->dst_port	= cpu_to_le32(dst_port);
>> +	hdr->flags	= cpu_to_le32(info->flags);
>> +	hdr->len	= cpu_to_le32(len);
>>
>>  	if (info->msg && len > 0) {
>> -		pkt->buf = kmalloc(len, GFP_KERNEL);
>> -		if (!pkt->buf)
>> -			goto out_pkt;
>> -
>> -		pkt->buf_len = len;
>> -
>> -		err = memcpy_from_msg(pkt->buf, info->msg, len);
>> +		payload = skb_put(skb, len);
>> +		err = memcpy_from_msg(payload, info->msg, len);
>>  		if (err)
>>  			goto out;
>>
>>  		if (msg_data_left(info->msg) == 0 &&
>>  		    info->type == VIRTIO_VSOCK_TYPE_SEQPACKET) {
>> -			pkt->hdr.flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
>> +			hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
>>
>>  			if (info->msg->msg_flags & MSG_EOR)
>> -				pkt->hdr.flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
>> +				hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
>>  		}
>>  	}
>>
>> +	if (info->reply)
>> +		virtio_vsock_skb_set_reply(skb);
>> +
>>  	trace_virtio_transport_alloc_pkt(src_cid, src_port,
>>  					 dst_cid, dst_port,
>>  					 len,
>> @@ -91,19 +94,18 @@ virtio_transport_alloc_pkt(struct virtio_vsock_pkt_info *info,
>>  					 info->op,
>>  					 info->flags);
>>
>> -	return pkt;
>> +	return skb;
>>
>>  out:
>> -	kfree(pkt->buf);
>> -out_pkt:
>> -	kfree(pkt);
>> +	virtio_vsock_kfree_skb(skb);
>>  	return NULL;
>>  }
>>
>>  /* Packet capture */
>>  static struct sk_buff *virtio_transport_build_skb(void *opaque)
>>  {
>> -	struct virtio_vsock_pkt *pkt = opaque;
>> +	struct virtio_vsock_hdr *pkt_hdr;
>> +	struct sk_buff *pkt = opaque;
>>  	struct af_vsockmon_hdr *hdr;
>>  	struct sk_buff *skb;
>>  	size_t payload_len;
>> @@ -113,10 +115,11 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
>>  	 * the payload length from the header and the buffer pointer taking
>>  	 * care of the offset in the original packet.
>>  	 */
>> -	payload_len = le32_to_cpu(pkt->hdr.len);
>> -	payload_buf = pkt->buf + pkt->off;
>> +	pkt_hdr = virtio_vsock_hdr(pkt);
>> +	payload_len = pkt->len;
>> +	payload_buf = pkt->data;
>>
>> -	skb = alloc_skb(sizeof(*hdr) + sizeof(pkt->hdr) + payload_len,
>> +	skb = alloc_skb(sizeof(*hdr) + sizeof(*pkt_hdr) + payload_len,
>>  			GFP_ATOMIC);
>>  	if (!skb)
>>  		return NULL;
>> @@ -124,16 +127,16 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
>>  	hdr = skb_put(skb, sizeof(*hdr));
>>
>>  	/* pkt->hdr is little-endian so no need to byteswap here */
>> -	hdr->src_cid = pkt->hdr.src_cid;
>> -	hdr->src_port = pkt->hdr.src_port;
>> -	hdr->dst_cid = pkt->hdr.dst_cid;
>> -	hdr->dst_port = pkt->hdr.dst_port;
>> +	hdr->src_cid = pkt_hdr->src_cid;
>> +	hdr->src_port = pkt_hdr->src_port;
>> +	hdr->dst_cid = pkt_hdr->dst_cid;
>> +	hdr->dst_port = pkt_hdr->dst_port;
>>
>>  	hdr->transport = cpu_to_le16(AF_VSOCK_TRANSPORT_VIRTIO);
>> -	hdr->len = cpu_to_le16(sizeof(pkt->hdr));
>> +	hdr->len = cpu_to_le16(sizeof(*pkt_hdr));
>>  	memset(hdr->reserved, 0, sizeof(hdr->reserved));
>>
>> -	switch (le16_to_cpu(pkt->hdr.op)) {
>> +	switch (le16_to_cpu(pkt_hdr->op)) {
>>  	case VIRTIO_VSOCK_OP_REQUEST:
>>  	case VIRTIO_VSOCK_OP_RESPONSE:
>>  		hdr->op = cpu_to_le16(AF_VSOCK_OP_CONNECT);
>> @@ -154,7 +157,7 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
>>  		break;
>>  	}
>>
>> -	skb_put_data(skb, &pkt->hdr, sizeof(pkt->hdr));
>> +	skb_put_data(skb, pkt_hdr, sizeof(*pkt_hdr));
>>
>>  	if (payload_len) {
>>  		skb_put_data(skb, payload_buf, payload_len);
>> @@ -163,13 +166,13 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
>>  	return skb;
>>  }
>>
>> -void virtio_transport_deliver_tap_pkt(struct virtio_vsock_pkt *pkt)
>> +void virtio_transport_deliver_tap_pkt(struct sk_buff *skb)
>>  {
>> -	if (pkt->tap_delivered)
>> +	if (virtio_vsock_skb_tap_delivered(skb))
>>  		return;
>>
>> -	vsock_deliver_tap(virtio_transport_build_skb, pkt);
>> -	pkt->tap_delivered = true;
>> +	vsock_deliver_tap(virtio_transport_build_skb, skb);
>> +	virtio_vsock_skb_set_tap_delivered(skb);
>>  }
>>  EXPORT_SYMBOL_GPL(virtio_transport_deliver_tap_pkt);
>>
>> @@ -192,8 +195,8 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
>>  	u32 src_cid, src_port, dst_cid, dst_port;
>>  	const struct virtio_transport *t_ops;
>>  	struct virtio_vsock_sock *vvs;
>> -	struct virtio_vsock_pkt *pkt;
>>  	u32 pkt_len = info->pkt_len;
>> +	struct sk_buff *skb;
>>
>>  	info->type = virtio_transport_get_type(sk_vsock(vsk));
>>
>> @@ -224,42 +227,47 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
>>  	if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
>>  		return pkt_len;
>>
>> -	pkt = virtio_transport_alloc_pkt(info, pkt_len,
>> +	skb = virtio_transport_alloc_skb(info, pkt_len,
>>  					 src_cid, src_port,
>>  					 dst_cid, dst_port);
>> -	if (!pkt) {
>> +	if (!skb) {
>>  		virtio_transport_put_credit(vvs, pkt_len);
>>  		return -ENOMEM;
>>  	}
>>
>> -	virtio_transport_inc_tx_pkt(vvs, pkt);
>> +	virtio_transport_inc_tx_pkt(vvs, skb);
>>
>> -	return t_ops->send_pkt(pkt);
>> +	return t_ops->send_pkt(skb);
>>  }
>>
>>  static bool virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs,
>> -					struct virtio_vsock_pkt *pkt)
>> +					struct sk_buff *skb)
>>  {
>> -	if (vvs->rx_bytes + pkt->len > vvs->buf_alloc)
>> +	if (vvs->rx_bytes + skb->len > vvs->buf_alloc)
>>  		return false;
>>
>> -	vvs->rx_bytes += pkt->len;
>> +	vvs->rx_bytes += skb->len;
>>  	return true;
>>  }
>>
>>  static void virtio_transport_dec_rx_pkt(struct virtio_vsock_sock *vvs,
>> -					struct virtio_vsock_pkt *pkt)
>> +					struct sk_buff *skb)
>>  {
>> -	vvs->rx_bytes -= pkt->len;
>> -	vvs->fwd_cnt += pkt->len;
>> +	int len;
>> +
>> +	len = skb_headroom(skb) - sizeof(struct virtio_vsock_hdr) - skb->len;
>> +	vvs->rx_bytes -= len;
>> +	vvs->fwd_cnt += len;
>>  }
>>
>> -void virtio_transport_inc_tx_pkt(struct virtio_vsock_sock *vvs, struct virtio_vsock_pkt *pkt)
>> +void virtio_transport_inc_tx_pkt(struct virtio_vsock_sock *vvs, struct sk_buff *skb)
>>  {
>> +	struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
>> +
>>  	spin_lock_bh(&vvs->rx_lock);
>>  	vvs->last_fwd_cnt = vvs->fwd_cnt;
>> -	pkt->hdr.fwd_cnt = cpu_to_le32(vvs->fwd_cnt);
>> -	pkt->hdr.buf_alloc = cpu_to_le32(vvs->buf_alloc);
>> +	hdr->fwd_cnt = cpu_to_le32(vvs->fwd_cnt);
>> +	hdr->buf_alloc = cpu_to_le32(vvs->buf_alloc);
>>  	spin_unlock_bh(&vvs->rx_lock);
>>  }
>>  EXPORT_SYMBOL_GPL(virtio_transport_inc_tx_pkt);
>> @@ -303,29 +311,29 @@ virtio_transport_stream_do_peek(struct vsock_sock *vsk,
>>  				size_t len)
>>  {
>>  	struct virtio_vsock_sock *vvs = vsk->trans;
>> -	struct virtio_vsock_pkt *pkt;
>>  	size_t bytes, total = 0, off;
>> +	struct sk_buff *skb, *tmp;
>>  	int err = -EFAULT;
>>
>>  	spin_lock_bh(&vvs->rx_lock);
>>
>> -	list_for_each_entry(pkt, &vvs->rx_queue, list) {
>> -		off = pkt->off;
>> +	skb_queue_walk_safe(&vvs->rx_queue, skb,  tmp) {
>> +		off = 0;
>>
>>  		if (total == len)
>>  			break;
>>
>> -		while (total < len && off < pkt->len) {
>> +		while (total < len && off < skb->len) {
>>  			bytes = len - total;
>> -			if (bytes > pkt->len - off)
>> -				bytes = pkt->len - off;
>> +			if (bytes > skb->len - off)
>> +				bytes = skb->len - off;
>>
>>  			/* sk_lock is held by caller so no one else can dequeue.
>>  			 * Unlock rx_lock since memcpy_to_msg() may sleep.
>>  			 */
>>  			spin_unlock_bh(&vvs->rx_lock);
>>
>> -			err = memcpy_to_msg(msg, pkt->buf + off, bytes);
>> +			err = memcpy_to_msg(msg, skb->data + off, bytes);
>>  			if (err)
>>  				goto out;
>>
>> @@ -352,37 +360,38 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
>>  				   size_t len)
>>  {
>>  	struct virtio_vsock_sock *vvs = vsk->trans;
>> -	struct virtio_vsock_pkt *pkt;
>>  	size_t bytes, total = 0;
>> -	u32 free_space;
>> +	struct sk_buff *skb;
>>  	int err = -EFAULT;
>> +	u32 free_space;
>>
>>  	spin_lock_bh(&vvs->rx_lock);
>> -	while (total < len && !list_empty(&vvs->rx_queue)) {
>> -		pkt = list_first_entry(&vvs->rx_queue,
>> -				       struct virtio_vsock_pkt, list);
>> +	while (total < len && !skb_queue_empty_lockless(&vvs->rx_queue)) {
>> +		skb = __skb_dequeue(&vvs->rx_queue);
>>
>>  		bytes = len - total;
>> -		if (bytes > pkt->len - pkt->off)
>> -			bytes = pkt->len - pkt->off;
>> +		if (bytes > skb->len)
>> +			bytes = skb->len;
>>
>>  		/* sk_lock is held by caller so no one else can dequeue.
>>  		 * Unlock rx_lock since memcpy_to_msg() may sleep.
>>  		 */
>>  		spin_unlock_bh(&vvs->rx_lock);
>>
>> -		err = memcpy_to_msg(msg, pkt->buf + pkt->off, bytes);
>> +		err = memcpy_to_msg(msg, skb->data, bytes);
>>  		if (err)
>>  			goto out;
>>
>>  		spin_lock_bh(&vvs->rx_lock);
>>
>>  		total += bytes;
>> -		pkt->off += bytes;
>> -		if (pkt->off == pkt->len) {
>> -			virtio_transport_dec_rx_pkt(vvs, pkt);
>> -			list_del(&pkt->list);
>> -			virtio_transport_free_pkt(pkt);
>> +		skb_pull(skb, bytes);
>> +
>> +		if (skb->len == 0) {
>> +			virtio_transport_dec_rx_pkt(vvs, skb);
>> +			virtio_vsock_consume_skb(skb);
>> +		} else {
>> +			__skb_queue_head(&vvs->rx_queue, skb);
>>  		}
>>  	}
>>
>> @@ -414,10 +423,10 @@ static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
>>  						 int flags)
>>  {
>>  	struct virtio_vsock_sock *vvs = vsk->trans;
>> -	struct virtio_vsock_pkt *pkt;
>>  	int dequeued_len = 0;
>>  	size_t user_buf_len = msg_data_left(msg);
>>  	bool msg_ready = false;
>> +	struct sk_buff *skb;
>>
>>  	spin_lock_bh(&vvs->rx_lock);
>>
>> @@ -427,13 +436,18 @@ static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
>>  	}
>>
>>  	while (!msg_ready) {
>> -		pkt = list_first_entry(&vvs->rx_queue, struct virtio_vsock_pkt, list);
>> +		struct virtio_vsock_hdr *hdr;
>> +
>> +		skb = __skb_dequeue(&vvs->rx_queue);
>> +		if (!skb)
>> +			break;
>> +		hdr = virtio_vsock_hdr(skb);
>>
>>  		if (dequeued_len >= 0) {
>>  			size_t pkt_len;
>>  			size_t bytes_to_copy;
>>
>> -			pkt_len = (size_t)le32_to_cpu(pkt->hdr.len);
>> +			pkt_len = (size_t)le32_to_cpu(hdr->len);
>>  			bytes_to_copy = min(user_buf_len, pkt_len);
>>
>>  			if (bytes_to_copy) {
>> @@ -444,7 +458,7 @@ static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
>>  				 */
>>  				spin_unlock_bh(&vvs->rx_lock);
>>
>> -				err = memcpy_to_msg(msg, pkt->buf, bytes_to_copy);
>> +				err = memcpy_to_msg(msg, skb->data, bytes_to_copy);
>>  				if (err) {
>>  					/* Copy of message failed. Rest of
>>  					 * fragments will be freed without copy.
>> @@ -452,6 +466,7 @@ static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
>>  					dequeued_len = err;
>>  				} else {
>>  					user_buf_len -= bytes_to_copy;
>> +					skb_pull(skb, bytes_to_copy);
>>  				}
>>
>>  				spin_lock_bh(&vvs->rx_lock);
>> @@ -461,17 +476,16 @@ static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
>>  				dequeued_len += pkt_len;
>>  		}
>>
>> -		if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOM) {
>> +		if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM) {
>>  			msg_ready = true;
>>  			vvs->msg_count--;
>>
>> -			if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOR)
>> +			if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOR)
>>  				msg->msg_flags |= MSG_EOR;
>>  		}
>>
>> -		virtio_transport_dec_rx_pkt(vvs, pkt);
>> -		list_del(&pkt->list);
>> -		virtio_transport_free_pkt(pkt);
>> +		virtio_transport_dec_rx_pkt(vvs, skb);
>> +		virtio_vsock_kfree_skb(skb);
>>  	}
>>
>>  	spin_unlock_bh(&vvs->rx_lock);
>> @@ -609,7 +623,7 @@ int virtio_transport_do_socket_init(struct vsock_sock *vsk,
>>
>>  	spin_lock_init(&vvs->rx_lock);
>>  	spin_lock_init(&vvs->tx_lock);
>> -	INIT_LIST_HEAD(&vvs->rx_queue);
>> +	skb_queue_head_init(&vvs->rx_queue);
>>
>>  	return 0;
>>  }
>> @@ -806,16 +820,16 @@ void virtio_transport_destruct(struct vsock_sock *vsk)
>>  EXPORT_SYMBOL_GPL(virtio_transport_destruct);
>>
>>  static int virtio_transport_reset(struct vsock_sock *vsk,
>> -				  struct virtio_vsock_pkt *pkt)
>> +				  struct sk_buff *skb)
>>  {
>>  	struct virtio_vsock_pkt_info info = {
>>  		.op = VIRTIO_VSOCK_OP_RST,
>> -		.reply = !!pkt,
>> +		.reply = !!skb,
>>  		.vsk = vsk,
>>  	};
>>
>>  	/* Send RST only if the original pkt is not a RST pkt */
>> -	if (pkt && le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_RST)
>> +	if (skb && le16_to_cpu(virtio_vsock_hdr(skb)->op) == VIRTIO_VSOCK_OP_RST)
>>  		return 0;
>>
>>  	return virtio_transport_send_pkt_info(vsk, &info);
>> @@ -825,29 +839,30 @@ static int virtio_transport_reset(struct vsock_sock *vsk,
>>   * attempt was made to connect to a socket that does not exist.
>>   */
>>  static int virtio_transport_reset_no_sock(const struct virtio_transport *t,
>> -					  struct virtio_vsock_pkt *pkt)
>> +					  struct sk_buff *skb)
>>  {
>> -	struct virtio_vsock_pkt *reply;
>> +	struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
>>  	struct virtio_vsock_pkt_info info = {
>>  		.op = VIRTIO_VSOCK_OP_RST,
>> -		.type = le16_to_cpu(pkt->hdr.type),
>> +		.type = le16_to_cpu(hdr->type),
>>  		.reply = true,
>>  	};
>> +	struct sk_buff *reply;
>>
>>  	/* Send RST only if the original pkt is not a RST pkt */
>> -	if (le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_RST)
>> +	if (le16_to_cpu(hdr->op) == VIRTIO_VSOCK_OP_RST)
>>  		return 0;
>>
>> -	reply = virtio_transport_alloc_pkt(&info, 0,
>> -					   le64_to_cpu(pkt->hdr.dst_cid),
>> -					   le32_to_cpu(pkt->hdr.dst_port),
>> -					   le64_to_cpu(pkt->hdr.src_cid),
>> -					   le32_to_cpu(pkt->hdr.src_port));
>> +	reply = virtio_transport_alloc_skb(&info, 0,
>> +					   le64_to_cpu(hdr->dst_cid),
>> +					   le32_to_cpu(hdr->dst_port),
>> +					   le64_to_cpu(hdr->src_cid),
>> +					   le32_to_cpu(hdr->src_port));
>>  	if (!reply)
>>  		return -ENOMEM;
>>
>>  	if (!t) {
>> -		virtio_transport_free_pkt(reply);
>> +		virtio_vsock_kfree_skb(reply);
>>  		return -ENOTCONN;
>>  	}
>>
>> @@ -858,16 +873,11 @@ static int virtio_transport_reset_no_sock(const struct virtio_transport *t,
>>  static void virtio_transport_remove_sock(struct vsock_sock *vsk)
>>  {
>>  	struct virtio_vsock_sock *vvs = vsk->trans;
>> -	struct virtio_vsock_pkt *pkt, *tmp;
>>
>>  	/* We don't need to take rx_lock, as the socket is closing and we are
>>  	 * removing it.
>>  	 */
>> -	list_for_each_entry_safe(pkt, tmp, &vvs->rx_queue, list) {
>> -		list_del(&pkt->list);
>> -		virtio_transport_free_pkt(pkt);
>> -	}
>> -
>> +	virtio_vsock_skb_queue_purge(&vvs->rx_queue);
>>  	vsock_remove_sock(vsk);
>>  }
>>
>> @@ -981,13 +991,14 @@ EXPORT_SYMBOL_GPL(virtio_transport_release);
>>
>>  static int
>>  virtio_transport_recv_connecting(struct sock *sk,
>> -				 struct virtio_vsock_pkt *pkt)
>> +				 struct sk_buff *skb)
>>  {
>> +	struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
>>  	struct vsock_sock *vsk = vsock_sk(sk);
>> -	int err;
>>  	int skerr;
>> +	int err;
>>
>> -	switch (le16_to_cpu(pkt->hdr.op)) {
>> +	switch (le16_to_cpu(hdr->op)) {
>>  	case VIRTIO_VSOCK_OP_RESPONSE:
>>  		sk->sk_state = TCP_ESTABLISHED;
>>  		sk->sk_socket->state = SS_CONNECTED;
>> @@ -1008,7 +1019,7 @@ virtio_transport_recv_connecting(struct sock *sk,
>>  	return 0;
>>
>>  destroy:
>> -	virtio_transport_reset(vsk, pkt);
>> +	virtio_transport_reset(vsk, skb);
>>  	sk->sk_state = TCP_CLOSE;
>>  	sk->sk_err = skerr;
>>  	sk_error_report(sk);
>> @@ -1017,34 +1028,37 @@ virtio_transport_recv_connecting(struct sock *sk,
>>
>>  static void
>>  virtio_transport_recv_enqueue(struct vsock_sock *vsk,
>> -			      struct virtio_vsock_pkt *pkt)
>> +			      struct sk_buff *skb)
>>  {
>>  	struct virtio_vsock_sock *vvs = vsk->trans;
>>  	bool can_enqueue, free_pkt = false;
>> +	struct virtio_vsock_hdr *hdr;
>> +	u32 len;
>>
>> -	pkt->len = le32_to_cpu(pkt->hdr.len);
>> -	pkt->off = 0;
>> +	hdr = virtio_vsock_hdr(skb);
>> +	len = le32_to_cpu(hdr->len);
>>
>>  	spin_lock_bh(&vvs->rx_lock);
>>
>> -	can_enqueue = virtio_transport_inc_rx_pkt(vvs, pkt);
>> +	can_enqueue = virtio_transport_inc_rx_pkt(vvs, skb);
>>  	if (!can_enqueue) {
>>  		free_pkt = true;
>>  		goto out;
>>  	}
>>
>> -	if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOM)
>> +	if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM)
>>  		vvs->msg_count++;
>>
>>  	/* Try to copy small packets into the buffer of last packet queued,
>>  	 * to avoid wasting memory queueing the entire buffer with a small
>>  	 * payload.
>>  	 */
>> -	if (pkt->len <= GOOD_COPY_LEN && !list_empty(&vvs->rx_queue)) {
>> -		struct virtio_vsock_pkt *last_pkt;
>> +	if (len <= GOOD_COPY_LEN && !skb_queue_empty_lockless(&vvs->rx_queue)) {
>> +		struct virtio_vsock_hdr *last_hdr;
>> +		struct sk_buff *last_skb;
>>
>> -		last_pkt = list_last_entry(&vvs->rx_queue,
>> -					   struct virtio_vsock_pkt, list);
>> +		last_skb = skb_peek_tail(&vvs->rx_queue);
>> +		last_hdr = virtio_vsock_hdr(last_skb);
>>
>>  		/* If there is space in the last packet queued, we copy the
>>  		 * new packet in its buffer. We avoid this if the last packet
>> @@ -1052,35 +1066,35 @@ virtio_transport_recv_enqueue(struct vsock_sock *vsk,
>  >  		 * delimiter of SEQPACKET message, so 'pkt' is the first packet
>>  		 * of a new message.
>>  		 */
>> -		if ((pkt->len <= last_pkt->buf_len - last_pkt->len) &&
>> -		    !(le32_to_cpu(last_pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOM)) {
>> -			memcpy(last_pkt->buf + last_pkt->len, pkt->buf,
>> -			       pkt->len);
>> -			last_pkt->len += pkt->len;
>> +		if (skb->len < skb_tailroom(last_skb) &&
>> +		    !(le32_to_cpu(last_hdr->flags) & VIRTIO_VSOCK_SEQ_EOM)) {
>> +			memcpy(skb_put(last_skb, skb->len), skb->data, skb->len);
>>  			free_pkt = true;
>> -			last_pkt->hdr.flags |= pkt->hdr.flags;
>> +			last_hdr->flags |= hdr->flags;
>> +			last_hdr->len = cpu_to_le32(skb->len);
>I think, it should be "last_hdr->len +=" instead of "last_hdr =". Because we append new payload
>to last skb, not replacing it.

Right, or just `last_hdr->len = cpu_to_le32(last_skb->len);`

I was confused between skb and last_skb when I reviewed!

Thanks,
Stefano