[RFC PATCH v1 05/12] vsock/virtio: non-linear skb support
From: Arseniy Krasnov <hidden>
Date: 2023-02-06 06:58:58
Also in:
kvm, lkml
Subsystem:
networking [general], the rest, virtio and vhost vsock driver, virtio core, vm sockets (af_vsock) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Stefan Hajnoczi, Stefano Garzarella, "Michael S. Tsirkin", Jason Wang
Use pages of non-linear skb as buffers in virtio tx queue. Signed-off-by: Arseniy Krasnov <redacted> --- net/vmw_vsock/virtio_transport.c | 31 +++++++++++++++++++++++++------ 1 file changed, 25 insertions(+), 6 deletions(-)
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 28b5a8e8e094..b8a7d6dc9f46 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c@@ -100,7 +100,8 @@ virtio_transport_send_pkt_work(struct work_struct *work) vq = vsock->vqs[VSOCK_VQ_TX]; for (;;) { - struct scatterlist hdr, buf, *sgs[2]; + struct scatterlist *sgs[MAX_SKB_FRAGS + 1]; + struct scatterlist bufs[MAX_SKB_FRAGS + 1]; int ret, in_sg = 0, out_sg = 0; struct sk_buff *skb; bool reply;
@@ -111,12 +112,30 @@ virtio_transport_send_pkt_work(struct work_struct *work) virtio_transport_deliver_tap_pkt(skb); reply = virtio_vsock_skb_reply(skb); + sg_init_one(&bufs[0], virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb))); + sgs[out_sg++] = &bufs[0]; + + if (skb_is_nonlinear(skb)) { + int i; + + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + struct page *data_page = skb_shinfo(skb)->frags[i].bv_page; + + /* We will use 'page_to_virt()' for userspace page here, + * because virtio layer will call 'virt_to_phys()' later + * to fill buffer descriptor. We don't touch memory at + * "virtual" address of this page. + */ + sg_init_one(&bufs[i + 1], + page_to_virt(data_page), PAGE_SIZE); + sgs[out_sg++] = &bufs[i + 1]; + } + } else { + if (skb->len > 0) { + sg_init_one(&bufs[1], skb->data, skb->len); + sgs[out_sg++] = &bufs[1]; + } - sg_init_one(&hdr, virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb))); - sgs[out_sg++] = &hdr; - 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, skb, GFP_KERNEL);
--
2.25.1