On Sat, Jun 03, 2023 at 11:49:24PM +0300, Arseniy Krasnov wrote:
This adds copying to guest's virtio buffers from non-linear skbs. Such
skbs are created by protocol layer when MSG_ZEROCOPY flags is used. It
changes call of 'copy_to_iter()' to 'skb_copy_datagram_iter()'. Second
function can read data from non-linear skb.

See commit to 'net/vmw_vsock/virtio_transport_common.c' with the same
name for more details.

I think it's okay if we report the same details here.


Signed-off-by: Arseniy Krasnov <avkras...@sberdevices.ru>
---
drivers/vhost/vsock.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 6578db78f0ae..b254aa4b756a 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -156,7 +156,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
                }

                iov_iter_init(&iov_iter, ITER_DEST, &vq->iov[out], in, iov_len);
-               payload_len = skb->len;
+               payload_len = skb->len - VIRTIO_VSOCK_SKB_CB(skb)->frag_off;

Also here a variable should make the code more readable.

Stefano

                hdr = virtio_vsock_hdr(skb);

                /* If the packet is greater than the space available in the
@@ -197,8 +197,10 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
                        break;
                }

-               nbytes = copy_to_iter(skb->data, payload_len, &iov_iter);
-               if (nbytes != payload_len) {
+               if (skb_copy_datagram_iter(skb,
+                                          VIRTIO_VSOCK_SKB_CB(skb)->frag_off,
+                                          &iov_iter,
+                                          payload_len)) {
                        kfree_skb(skb);
                        vq_err(vq, "Faulted on copying pkt buf\n");
                        break;
@@ -212,13 +214,13 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
                vhost_add_used(vq, head, sizeof(*hdr) + payload_len);
                added = true;

-               skb_pull(skb, payload_len);
+               VIRTIO_VSOCK_SKB_CB(skb)->frag_off += 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 (skb->len > 0) {
+               if (VIRTIO_VSOCK_SKB_CB(skb)->frag_off < skb->len) {
                        hdr->flags |= cpu_to_le32(flags_to_restore);

                        /* We are queueing the same skb to handle
--
2.25.1


_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization

Reply via email to