udp_vu_sock_recv() currently mixes two concerns: receiving data from the
socket and managing virtqueue buffers (collecting, rewinding, releasing).
This makes the function harder to reason about and couples socket I/O
with virtqueue state.
Move all virtqueue operations, vu_collect(), vu_init_elem(),
vu_queue_rewind(), and the queue-readiness check, into
udp_vu_sock_to_tap(), which is the only caller. This turns
udp_vu_sock_recv() into a pure socket receive function that simply reads
into the provided iov_tail and adjusts its length.
Signed-off-by: Laurent Vivier
---
udp_vu.c | 79 ++++++++++++++++++++++++++------------------------------
1 file changed, 37 insertions(+), 42 deletions(-)
diff --git a/udp_vu.c b/udp_vu.c
index 8f4d0aedac10..aefcab0b86c2 100644
--- a/udp_vu.c
+++ b/udp_vu.c
@@ -58,75 +58,41 @@ static size_t udp_vu_hdrlen(bool v6)
/**
* udp_vu_sock_recv() - Receive datagrams from socket into vhost-user buffers
- * @c: Execution context
* @data: IO vector tail for the frame (modified on output)
- * @vq: virtqueue to use to receive data
* @s: Socket to receive from
* @v6: Set for IPv6 connections
*
- * Return: size of received data, 0 if the datagram
- * was discarded because the virtqueue is not ready, -1 on error
+ * Return: size of received data, -1 on error
*/
-static ssize_t udp_vu_sock_recv(const struct ctx *c, struct iov_tail *data,
- struct vu_virtq *vq, int s, bool v6)
+static ssize_t udp_vu_sock_recv(struct iov_tail *data, int s, bool v6)
{
- const struct vu_dev *vdev = c->vdev;
- struct msghdr msg = { 0 };
+ struct iovec msg_iov[data->cnt];
+ struct msghdr msg = { 0 };
struct iov_tail payload;
size_t hdrlen;
ssize_t dlen;
- int iov_cnt;
-
- ASSERT(!c->no_udp);
-
- if (!vu_queue_enabled(vq) || !vu_queue_started(vq)) {
- debug("Got UDP packet, but RX virtqueue not usable yet");
-
- if (recvmsg(s, &msg, MSG_DONTWAIT) < 0)
- debug_perror("Failed to discard datagram");
-
- data->cnt = 0;
- return 0;
- }
/* compute L2 header length */
hdrlen = udp_vu_hdrlen(v6);
- vu_init_elem(elem, (struct iovec *)data->iov, data->cnt);
-
- iov_cnt = vu_collect(vdev, vq, elem, ARRAY_SIZE(elem),
- IP_MAX_MTU + ETH_HLEN + VNET_HLEN, NULL);
- if (iov_cnt == 0)
- return -1;
-
- data->cnt = iov_cnt;
-
/* reserve space for the headers */
ASSERT(iov_tail_size(data) >= MAX(hdrlen, ETH_ZLEN + VNET_HLEN));
payload = *data;
iov_drop_header(&payload, hdrlen);
- struct iovec msg_iov[payload.cnt];
msg.msg_iov = msg_iov;
msg.msg_iovlen = iov_tail_clone(msg.msg_iov, payload.cnt, &payload);
/* read data from the socket */
dlen = recvmsg(s, &msg, 0);
- if (dlen < 0) {
- vu_queue_rewind(vq, iov_cnt);
+ if (dlen < 0)
return -1;
- }
iov_tail_truncate(data, MAX(dlen + hdrlen, ETH_ZLEN + VNET_HLEN));
iov_tail_zero_end(data, dlen + hdrlen);
iov_tail_truncate(data, dlen + hdrlen);
- vu_set_vnethdr(vdev, data->iov[0].iov_base, data->cnt);
-
- /* release unused buffers */
- vu_queue_rewind(vq, iov_cnt - data->cnt);
-
return dlen;
}
@@ -216,16 +182,45 @@ void udp_vu_sock_to_tap(const struct ctx *c, int s, int n, flow_sidx_t tosidx)
struct iov_tail data;
int i;
+ ASSERT(!c->no_udp);
+
+ if (!vu_queue_enabled(vq) || !vu_queue_started(vq)) {
+ struct msghdr msg = { 0 };
+
+ debug("Got UDP packet, but RX virtqueue not usable yet");
+
+ for (i = 0; i < n; i++) {
+ if (recvmsg(s, &msg, MSG_DONTWAIT) < 0)
+ debug_perror("Failed to discard datagram");
+ }
+
+ return;
+ }
+
for (i = 0; i < n; i++) {
ssize_t dlen;
+ int elem_cnt;
- data = IOV_TAIL(iov_vu, VIRTQUEUE_MAX_SIZE, 0);
+ vu_init_elem(elem, iov_vu, ARRAY_SIZE(elem));
- dlen = udp_vu_sock_recv(c, &data, vq, s, v6);
- if (dlen < 0)
+ elem_cnt = vu_collect(vdev, vq, elem, ARRAY_SIZE(elem),
+ IP_MAX_MTU + ETH_HLEN + VNET_HLEN, NULL);
+ if (elem_cnt == 0)
break;
+ data = IOV_TAIL(iov_vu, elem_cnt, 0);
+
+ dlen = udp_vu_sock_recv(&data, s, v6);
+ if (dlen < 0) {
+ vu_queue_rewind(vq, elem_cnt);
+ continue;
+ }
+
+ /* release unused buffers */
+ vu_queue_rewind(vq, elem_cnt - data.cnt);
+
if (data.cnt > 0) {
+ vu_set_vnethdr(vdev, data.iov[0].iov_base, data.cnt);
udp_vu_prepare(c, &data, toside, dlen);
if (*c->pcap) {
udp_vu_csum(toside, &data);
--
2.53.0