[RFC PATCH v3 02/17] vhost/vsock: read data from non-linear skb
From: Arseniy Krasnov <hidden>
Date: 2023-05-22 07:45:27
Also in:
kvm, lkml
Subsystem:
the rest, virtio and vhost vsock driver, virtio host (vhost) · Maintainers:
Linus Torvalds, Stefan Hajnoczi, Stefano Garzarella, "Michael S. Tsirkin", Jason Wang
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. Signed-off-by: Arseniy Krasnov <redacted> --- 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; 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