Re: [RFC PATCH v4 02/17] vhost/vsock: read data from non-linear skb

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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 <AVKrasnov@xxxxxxxxxxxxxx>
---
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





[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]

  Powered by Linux