Use pages of non-linear skb as buffers in virtio tx queue.
Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
---
net/vmw_vsock/virtio_transport.c | 32 ++++++++++++++++++++++++++------
1 file changed, 26 insertions(+), 6 deletions(-)
@@ -100,7 +100,9 @@ virtio_transport_send_pkt_work(struct work_struct *work)
vq = vsock->vqs[VSOCK_VQ_TX];
for (;;) {
- struct scatterlist hdr, buf, *sgs[2];
+ /* +1 is for packet header. */
+ 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 +113,30 @@ 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);