Re: [PATCH net-next v8] virtio/vsock: replace virtio_vsock_pkt with sk_buff

Michael S. Tsirkin
2022-12-15T09:05:59Z

On Thu, Dec 15, 2022 at 09:47:57AM +0100, Stefano Garzarella wrote:
> On Thu, Dec 15, 2022 at 04:36:44AM +0000, 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>
> > ---
> >
> > Testing: passed vsock_test h2g and g2h
> > Note2: net-next is closed, but sending out now in case more comments
> > roll in, as discussed here:
> > https://lore.kernel.org/all/Y34SoH1nFTXXLWbK@bullseye/
> >
> > Changes in v8:
> > - vhost/vsock: remove unused enum
> > - vhost/vsock: use spin_lock_bh() instead of spin_lock()
> > - vsock/loopback: use __skb_dequeue instead of skb_dequeue
> >
> > Changes in v7:
> > - use skb_queue_empty() instead of skb_queue_empty_lockless()
> >
> > Changes in v6:
> > - use skb->cb instead of skb->_skb_refdst
> > - use lock-free __skb_queue_purge for rx_queue when rx_lock held
> >
> > Changes in v5:
> > - last_skb instead of skb: last_hdr->len = cpu_to_le32(last_skb->len)
> >
> > 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 | 126 +++++--
> > 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, 495 insertions(+), 466 deletions(-)
> >
> > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> > index 5703775af129..ee0a00432cb1 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_bh(&vsock->send_pkt_queue.lock);
> > + skb = __skb_dequeue(&vsock->send_pkt_queue);
> > + spin_unlock_bh(&vsock->send_pkt_queue.lock);
>
> Sorry for coming late, but I just commented in Paolo's reply.
> Here I think we can directly use the new virtio_vsock_skb_dequeue().

Yea, pretty late.
And using that will prevent me from merging this since it's not in my tree yet.
We can do a cleanup patch on top.

> With that fixed, you can put my R-b:
>
> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
>
> Below I left a little comment.
>
> > +
> > + 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);
> > + 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)) {
> > + 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)) {
> > + 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);
> > + 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);
> > + 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);
> > + 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);
> > + 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) {
> > + 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);
> > + 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);
> > + 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..7ed943615271 100644
> > --- a/include/linux/virtio_vsock.h
> > +++ b/include/linux/virtio_vsock.h
> > @@ -7,6 +7,106 @@
> > #include <net/sock.h>
> > #include <net/af_vsock.h>
> >
> > +#define VIRTIO_VSOCK_SKB_HEADROOM (sizeof(struct virtio_vsock_hdr))
> > +
> > +struct virtio_vsock_skb_cb {
> > + bool reply;
> > + bool tap_delivered;
> > +};
> > +
> > +#define VIRTIO_VSOCK_SKB_CB(skb) ((struct virtio_vsock_skb_cb *)((skb)->cb))
> > +
> > +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 VIRTIO_VSOCK_SKB_CB(skb)->reply;
> > +}
> > +
> > +static inline void virtio_vsock_skb_set_reply(struct sk_buff *skb)
> > +{
> > + VIRTIO_VSOCK_SKB_CB(skb)->reply = true;
> > +}
> > +
> > +static inline bool virtio_vsock_skb_tap_delivered(struct sk_buff *skb)
> > +{
> > + return VIRTIO_VSOCK_SKB_CB(skb)->tap_delivered;
> > +}
> > +
> > +static inline void virtio_vsock_skb_set_tap_delivered(struct sk_buff *skb)
> > +{
> > + VIRTIO_VSOCK_SKB_CB(skb)->tap_delivered = true;
> > +}
> > +
> > +static inline void virtio_vsock_skb_clear_tap_delivered(struct sk_buff *skb)
> > +{
> > + VIRTIO_VSOCK_SKB_CB(skb)->tap_delivered = false;
> > +}
>
> Maybe, we can have a single
>
> virtio_vsock_skb_set_tap_delivered(struct sk_buff *skb,
> bool tap_delivered)
>
> to be used in both cases.
>
> Anyway, I don't have a strong opinion on that.
>
> Thanks,
> Stefano