On Fri, Feb 27, 2026 at 03:03:26PM +0100, Laurent Vivier wrote:
Refactor vu_set_vnethdr() to take an iov_tail pointer instead of a direct pointer to the virtio_net_hdr_mrg_rxbuf structure. This makes the function use IOV_PEEK_HEADER() and IOV_PUT_HEADER() to read and write the virtio-net header through the iov_tail abstraction.
Signed-off-by: Laurent Vivier
LGTM, with one nit.
--- tcp_vu.c | 8 +++++--- udp_vu.c | 3 +-- vu_common.c | 24 ++++++++++++++++-------- vu_common.h | 3 +-- 4 files changed, 23 insertions(+), 15 deletions(-)
diff --git a/tcp_vu.c b/tcp_vu.c index 98e5974fee0e..92667507ac9b 100644 --- a/tcp_vu.c +++ b/tcp_vu.c @@ -94,10 +94,11 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags) if (elem_cnt != 1) return -1;
- ASSERT(flags_elem[0].in_sg[0].iov_len >= + payload = IOV_TAIL(&flags_elem[0].in_sg[0], elem_cnt, 0);
Shouldn't a later initialization of payload be removed to match this?
+ ASSERT(iov_tail_size(&payload) >= MAX(hdrlen + sizeof(*opts), ETH_ZLEN + VNET_HLEN));
- vu_set_vnethdr(vdev, flags_elem[0].in_sg[0].iov_base, 1); + vu_set_vnethdr(vdev, &payload, 1);
eh = vu_eth(flags_elem[0].in_sg[0].iov_base);
@@ -448,11 +449,12 @@ int tcp_vu_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn) for (i = 0, previous_dlen = -1, check = NULL; i < head_cnt; i++) { struct iovec *iov = &elem[head[i]].in_sg[0]; int buf_cnt = head[i + 1] - head[i]; + struct iov_tail data = IOV_TAIL(iov, buf_cnt, 0); ssize_t dlen = iov_size(iov, buf_cnt) - hdrlen; bool push = i == head_cnt - 1; size_t l2len;
- vu_set_vnethdr(vdev, iov->iov_base, buf_cnt); + vu_set_vnethdr(vdev, &data, buf_cnt);
/* The IPv4 header checksum varies only with dlen */ if (previous_dlen != dlen) diff --git a/udp_vu.c b/udp_vu.c index 6d87f4872268..5ae79b9bb0c5 100644 --- a/udp_vu.c +++ b/udp_vu.c @@ -234,8 +234,7 @@ void udp_vu_sock_to_tap(const struct ctx *c, int s, int n, flow_sidx_t tosidx) vu_queue_rewind(vq, elem_cnt - elem_used);
if (data.cnt > 0) { - vu_set_vnethdr(vdev, data.iov[0].iov_base, elem_used); - iov_drop_header(&data, VNET_HLEN); + vu_set_vnethdr(vdev, &data, elem_used); udp_vu_prepare(c, &data, toside); if (*c->pcap) { udp_vu_csum(toside, &data); diff --git a/vu_common.c b/vu_common.c index 7a8cd18f4e81..a8d5fcdaea83 100644 --- a/vu_common.c +++ b/vu_common.c @@ -120,18 +120,25 @@ int vu_collect(const struct vu_dev *vdev, struct vu_virtq *vq, }
/** - * vu_set_vnethdr() - set virtio-net headers + * vu_set_vnethdr() - set virtio-net header * @vdev: vhost-user device - * @vnethdr: Address of the header to set + * @data: IOV tail to write header to, updated to + * point after the virtio-net header * @num_buffers: Number of guest buffers of the frame */ -void vu_set_vnethdr(const struct vu_dev *vdev, - struct virtio_net_hdr_mrg_rxbuf *vnethdr, +void vu_set_vnethdr(const struct vu_dev *vdev, struct iov_tail *data, int num_buffers) { + struct virtio_net_hdr_mrg_rxbuf vnethdr_storage, *vnethdr; + + vnethdr = IOV_PEEK_HEADER(data, vnethdr_storage); + vnethdr->hdr = VU_HEADER; + if (vu_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF)) vnethdr->num_buffers = htole16(num_buffers); + + IOV_PUT_HEADER(data, vnethdr); }
/** @@ -248,6 +255,7 @@ int vu_send_single(const struct ctx *c, const void *buf, size_t size) struct vu_virtq *vq = &vdev->vq[VHOST_USER_RX_QUEUE]; struct vu_virtq_element elem[VIRTQUEUE_MAX_SIZE]; struct iovec in_sg[VIRTQUEUE_MAX_SIZE]; + struct iov_tail data; size_t total; int elem_cnt; int i; @@ -269,15 +277,15 @@ int vu_send_single(const struct ctx *c, const void *buf, size_t size) goto err; }
- vu_set_vnethdr(vdev, in_sg[0].iov_base, elem_cnt); - + data = IOV_TAIL(&in_sg[0], elem_cnt, 0); + vu_set_vnethdr(vdev, &data, elem_cnt); total -= VNET_HLEN;
/* copy data from the buffer to the iovec */ - iov_from_buf(in_sg, elem_cnt, VNET_HLEN, buf, total); + iov_from_buf(data.iov, data.cnt, data.off, buf, total);
if (*c->pcap) - pcap_iov(in_sg, elem_cnt, VNET_HLEN); + pcap_iov(data.iov, data.cnt, data.off);
vu_flush(vdev, vq, elem, elem_cnt);
diff --git a/vu_common.h b/vu_common.h index 052aff710502..41cf18936300 100644 --- a/vu_common.h +++ b/vu_common.h @@ -49,8 +49,7 @@ void vu_init_elem(struct vu_virtq_element *elem, struct iovec *iov, int vu_collect(const struct vu_dev *vdev, struct vu_virtq *vq, struct vu_virtq_element *elem, int max_elem, size_t size, size_t *collected); -void vu_set_vnethdr(const struct vu_dev *vdev, - struct virtio_net_hdr_mrg_rxbuf *vnethdr, +void vu_set_vnethdr(const struct vu_dev *vdev, struct iov_tail *data, int num_buffers); void vu_flush(const struct vu_dev *vdev, struct vu_virtq *vq, struct vu_virtq_element *elem, int elem_cnt); -- 2.53.0
-- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson