[PATCH v5 2/8] vu_common: Move vnethdr setup into vu_flush()

[Laurent Vivier <lvivier@redhat.com>]

Every caller of vu_flush() was calling vu_set_vnethdr() beforehand with
the same pattern.  Move it into vu_flush().

Remove vu_queue_notify() from vu_flush() and let callers invoke it
explicitly.  This allows paths that perform multiple flushes, such as
tcp_vu_send_flag() and tcp_vu_data_from_sock(), to issue a single guest
notification at the end.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 tcp_vu.c    | 19 ++++++++-----------
 udp_vu.c    |  3 +--
 vu_common.c |  9 +++++----
 vu_common.h |  1 -
 4 files changed, 14 insertions(+), 18 deletions(-)

diff --git a/tcp_vu.c b/tcp_vu.c
index dc0e17c0f03f..0cd01190d612 100644
--- a/tcp_vu.c
+++ b/tcp_vu.c
@@ -82,7 +82,6 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
 	struct ethhdr *eh;
 	uint32_t seq;
 	int elem_cnt;
-	int nb_ack;
 	int ret;
 
 	hdrlen = tcp_vu_hdrlen(CONN_V6(conn));
@@ -97,8 +96,6 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
 	assert(flags_elem[0].in_sg[0].iov_len >=
 	       MAX(hdrlen + sizeof(*opts), ETH_ZLEN + VNET_HLEN));
 
-	vu_set_vnethdr(flags_elem[0].in_sg[0].iov_base, 1);
-
 	eh = vu_eth(flags_elem[0].in_sg[0].iov_base);
 
 	memcpy(eh->h_dest, c->guest_mac, sizeof(eh->h_dest));
@@ -143,9 +140,10 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
 	l2len = optlen + hdrlen - VNET_HLEN;
 	vu_pad(&flags_elem[0].in_sg[0], l2len);
 
+	vu_flush(vdev, vq, flags_elem, 1);
+
 	if (*c->pcap)
 		pcap_iov(&flags_elem[0].in_sg[0], 1, VNET_HLEN);
-	nb_ack = 1;
 
 	if (flags & DUP_ACK) {
 		elem_cnt = vu_collect(vdev, vq, &flags_elem[1], 1,
@@ -157,14 +155,14 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
 			memcpy(flags_elem[1].in_sg[0].iov_base,
 			       flags_elem[0].in_sg[0].iov_base,
 			       flags_elem[0].in_sg[0].iov_len);
-			nb_ack++;
+
+			vu_flush(vdev, vq, &flags_elem[1], 1);
 
 			if (*c->pcap)
 				pcap_iov(&flags_elem[1].in_sg[0], 1, VNET_HLEN);
 		}
 	}
-
-	vu_flush(vdev, vq, flags_elem, nb_ack);
+	vu_queue_notify(vdev, vq);
 
 	return 0;
 }
@@ -451,7 +449,6 @@ int tcp_vu_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn)
 		assert(frame_size >= hdrlen);
 
 		dlen = frame_size - hdrlen;
-		vu_set_vnethdr(iov->iov_base, buf_cnt);
 
 		/* The IPv4 header checksum varies only with dlen */
 		if (previous_dlen != dlen)
@@ -464,14 +461,14 @@ int tcp_vu_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn)
 		l2len = dlen + hdrlen - VNET_HLEN;
 		vu_pad(iov, l2len);
 
+		vu_flush(vdev, vq, &elem[head[i]], buf_cnt);
+
 		if (*c->pcap)
 			pcap_iov(iov, buf_cnt, VNET_HLEN);
 
 		conn->seq_to_tap += dlen;
 	}
-
-	/* send packets */
-	vu_flush(vdev, vq, elem, iov_cnt);
+	vu_queue_notify(vdev, vq);
 
 	conn_flag(c, conn, ACK_FROM_TAP_DUE);
 
diff --git a/udp_vu.c b/udp_vu.c
index cc69654398f0..f8629af58ab5 100644
--- a/udp_vu.c
+++ b/udp_vu.c
@@ -124,8 +124,6 @@ static int udp_vu_sock_recv(const struct ctx *c, struct vu_virtq *vq, int s,
 	l2len = *dlen + hdrlen - VNET_HLEN;
 	vu_pad(&iov_vu[0], l2len);
 
-	vu_set_vnethdr(iov_vu[0].iov_base, elem_used);
-
 	/* release unused buffers */
 	vu_queue_rewind(vq, elem_cnt - elem_used);
 
@@ -230,6 +228,7 @@ void udp_vu_sock_to_tap(const struct ctx *c, int s, int n, flow_sidx_t tosidx)
 				pcap_iov(iov_vu, iov_used, VNET_HLEN);
 			}
 			vu_flush(vdev, vq, elem, iov_used);
+			vu_queue_notify(vdev, vq);
 		}
 	}
 }
diff --git a/vu_common.c b/vu_common.c
index 92381cd33c85..7627fad5976b 100644
--- a/vu_common.c
+++ b/vu_common.c
@@ -118,7 +118,8 @@ int vu_collect(const struct vu_dev *vdev, struct vu_virtq *vq,
  * @vnethdr:		Address of the header to set
  * @num_buffers:	Number of guest buffers of the frame
  */
-void vu_set_vnethdr(struct virtio_net_hdr_mrg_rxbuf *vnethdr, int num_buffers)
+static void vu_set_vnethdr(struct virtio_net_hdr_mrg_rxbuf *vnethdr,
+			   int num_buffers)
 {
 	vnethdr->hdr = VU_HEADER;
 	/* Note: if VIRTIO_NET_F_MRG_RXBUF is not negotiated,
@@ -139,6 +140,8 @@ void vu_flush(const struct vu_dev *vdev, struct vu_virtq *vq,
 {
 	int i;
 
+	vu_set_vnethdr(elem[0].in_sg[0].iov_base, elem_cnt);
+
 	for (i = 0; i < elem_cnt; i++) {
 		size_t elem_size = iov_size(elem[i].in_sg, elem[i].in_num);
 
@@ -146,7 +149,6 @@ void vu_flush(const struct vu_dev *vdev, struct vu_virtq *vq,
 	}
 
 	vu_queue_flush(vdev, vq, elem_cnt);
-	vu_queue_notify(vdev, vq);
 }
 
 /**
@@ -260,8 +262,6 @@ int vu_send_single(const struct ctx *c, const void *buf, size_t size)
 		goto err;
 	}
 
-	vu_set_vnethdr(in_sg[0].iov_base, elem_cnt);
-
 	total -= VNET_HLEN;
 
 	/* copy data from the buffer to the iovec */
@@ -271,6 +271,7 @@ int vu_send_single(const struct ctx *c, const void *buf, size_t size)
 		pcap_iov(in_sg, in_total, VNET_HLEN);
 
 	vu_flush(vdev, vq, elem, elem_cnt);
+	vu_queue_notify(vdev, vq);
 
 	trace("vhost-user sent %zu", total);
 
diff --git a/vu_common.h b/vu_common.h
index 7b060eb6184f..4037ab765b7d 100644
--- a/vu_common.h
+++ b/vu_common.h
@@ -39,7 +39,6 @@ int vu_collect(const struct vu_dev *vdev, struct vu_virtq *vq,
 	       struct vu_virtq_element *elem, int max_elem,
 	       struct iovec *in_sg, size_t max_in_sg, size_t *in_total,
 	       size_t size, size_t *collected);
-void vu_set_vnethdr(struct virtio_net_hdr_mrg_rxbuf *vnethdr, int num_buffers);
 void vu_flush(const struct vu_dev *vdev, struct vu_virtq *vq,
 	      struct vu_virtq_element *elem, int elem_cnt);
 void vu_kick_cb(struct vu_dev *vdev, union epoll_ref ref,
-- 
2.53.0