Re: [PATCH net-next v8 03/14] vsock: add netns to vsock skb cb

Stefano Garzarella
2025-11-06T16:17:37Z

On Thu, Oct 23, 2025 at 11:27:42AM -0700, Bobby Eshleman wrote:
>From: Bobby Eshleman <bobbyeshleman@meta.com>
>
>Add a net pointer and net_mode to the vsock skb and helpers for
>getting/setting them. When skbs are received the transport needs a way
>to tell the vsock layer and/or virtio common layer which namespace and
>what namespace mode the packet belongs to. This will be used by those
>upper layers for finding the correct socket object. This patch stashes
>these fields in the skb control buffer.
>
>This extends virtio_vsock_skb_cb to 24 bytes:
>
>struct virtio_vsock_skb_cb {
> struct net * net; /* 0 8 */
> enum vsock_net_mode net_mode; /* 8 4 */
> u32 offset; /* 12 4 */
> bool reply; /* 16 1 */
> bool tap_delivered; /* 17 1 */
>
> /* size: 24, cachelines: 1, members: 5 */
> /* padding: 6 */
> /* last cacheline: 24 bytes */
>};
>
>Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
>---
>Changes in v7:
>- rename `orig_net_mode` to `net_mode`
>- update commit message with a more complete explanation of changes
>
>Changes in v5:
>- some diff context change due to rebase to current net-next
>---
> include/linux/virtio_vsock.h | 23 +++++++++++++++++++++++
> 1 file changed, 23 insertions(+)

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

>
>diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>index 87cf4dcac78a..7f334a32133c 100644
>--- a/include/linux/virtio_vsock.h
>+++ b/include/linux/virtio_vsock.h
>@@ -10,6 +10,8 @@
> #define VIRTIO_VSOCK_SKB_HEADROOM (sizeof(struct virtio_vsock_hdr))
>
> struct virtio_vsock_skb_cb {
>+ struct net *net;
>+ enum vsock_net_mode net_mode;
> u32 offset;
> bool reply;
> bool tap_delivered;
>@@ -130,6 +132,27 @@ static inline size_t virtio_vsock_skb_len(struct sk_buff *skb)
> return (size_t)(skb_end_pointer(skb) - skb->head);
> }
>
>+static inline struct net *virtio_vsock_skb_net(struct sk_buff *skb)
>+{
>+ return VIRTIO_VSOCK_SKB_CB(skb)->net;
>+}
>+
>+static inline void virtio_vsock_skb_set_net(struct sk_buff *skb, struct net *net)
>+{
>+ VIRTIO_VSOCK_SKB_CB(skb)->net = net;
>+}
>+
>+static inline enum vsock_net_mode virtio_vsock_skb_net_mode(struct sk_buff *skb)
>+{
>+ return VIRTIO_VSOCK_SKB_CB(skb)->net_mode;
>+}
>+
>+static inline void virtio_vsock_skb_set_net_mode(struct sk_buff *skb,
>+ enum vsock_net_mode net_mode)
>+{
>+ VIRTIO_VSOCK_SKB_CB(skb)->net_mode = net_mode;
>+}
>+
> /* Dimension the RX SKB so that the entire thing fits exactly into
> * a single 4KiB page. This avoids wasting memory due to alloc_skb()
> * rounding up to the next page order and also means that we
>
>--
>2.47.3
>