[dpdk-dev] [PATCH v4 2/2] net/virtio: move VLAN tag insertion to Tx prepare

[Andrew Rybchenko]

From: Dilshod Urazov <Dilshod.Urazov at oktetlabs.ru>

VLAN tag insertion should be in Tx prepare, not in Tx burst functions.
One of Tx prepare goals is to be able to do preparations in advance
(possibliy on different CPU core) and then transmit it fast.
Also Tx prepare can report that a packet does not pass Tx offloads
check. E.g. has no enough headroom to insert VLAN header.

Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
Cc: stable at dpdk.org

Signed-off-by: Dilshod Urazov <Dilshod.Urazov at oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <arybchenko at solarflare.com>
---
v4:
 - add more details to commit log

 drivers/net/virtio/virtio_rxtx.c | 50 +++++++++-----------------------
 1 file changed, 14 insertions(+), 36 deletions(-)

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index 07f8f47de..dcce39e8c 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -1966,6 +1966,20 @@ virtio_xmit_pkts_prepare(void *tx_queue __rte_unused, struct rte_mbuf **tx_pkts,
 		}
 #endif
 
+		/* Do VLAN tag insertion */
+		if (unlikely(m->ol_flags & PKT_TX_VLAN_PKT)) {
+			error = rte_vlan_insert(&m);
+			/* rte_vlan_insert() may change pointer
+			 * even in the case of failure
+			 */
+			tx_pkts[nb_tx] = m;
+
+			if (unlikely(error)) {
+				rte_errno = -error;
+				break;
+			}
+		}
+
 		error = rte_net_intel_cksum_prepare(m);
 		if (unlikely(error)) {
 			rte_errno = -error;
@@ -1989,7 +2003,6 @@ virtio_xmit_pkts_packed(void *tx_queue, struct rte_mbuf **tx_pkts,
 	uint16_t hdr_size = hw->vtnet_hdr_size;
 	uint16_t nb_tx = 0;
 	bool in_order = hw->use_inorder_tx;
-	int error;
 
 	if (unlikely(hw->started == 0 && tx_pkts != hw->inject_pkts))
 		return nb_tx;
@@ -2007,17 +2020,6 @@ virtio_xmit_pkts_packed(void *tx_queue, struct rte_mbuf **tx_pkts,
 		struct rte_mbuf *txm = tx_pkts[nb_tx];
 		int can_push = 0, slots, need;
 
-		/* Do VLAN tag insertion */
-		if (unlikely(txm->ol_flags & PKT_TX_VLAN_PKT)) {
-			error = rte_vlan_insert(&txm);
-			if (unlikely(error)) {
-				rte_pktmbuf_free(txm);
-				continue;
-			}
-			/* vlan_insert may add a header mbuf */
-			tx_pkts[nb_tx] = txm;
-		}
-
 		/* optimize ring usage */
 		if ((vtpci_with_feature(hw, VIRTIO_F_ANY_LAYOUT) ||
 		      vtpci_with_feature(hw, VIRTIO_F_VERSION_1)) &&
@@ -2077,7 +2079,6 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 	struct virtio_hw *hw = vq->hw;
 	uint16_t hdr_size = hw->vtnet_hdr_size;
 	uint16_t nb_used, nb_tx = 0;
-	int error;
 
 	if (unlikely(hw->started == 0 && tx_pkts != hw->inject_pkts))
 		return nb_tx;
@@ -2096,17 +2097,6 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 		struct rte_mbuf *txm = tx_pkts[nb_tx];
 		int can_push = 0, use_indirect = 0, slots, need;
 
-		/* Do VLAN tag insertion */
-		if (unlikely(txm->ol_flags & PKT_TX_VLAN_PKT)) {
-			error = rte_vlan_insert(&txm);
-			if (unlikely(error)) {
-				rte_pktmbuf_free(txm);
-				continue;
-			}
-			/* vlan_insert may add a header mbuf */
-			tx_pkts[nb_tx] = txm;
-		}
-
 		/* optimize ring usage */
 		if ((vtpci_with_feature(hw, VIRTIO_F_ANY_LAYOUT) ||
 		      vtpci_with_feature(hw, VIRTIO_F_VERSION_1)) &&
@@ -2176,7 +2166,6 @@ virtio_xmit_pkts_inorder(void *tx_queue,
 	uint16_t hdr_size = hw->vtnet_hdr_size;
 	uint16_t nb_used, nb_avail, nb_tx = 0, nb_inorder_pkts = 0;
 	struct rte_mbuf *inorder_pkts[nb_pkts];
-	int error;
 
 	if (unlikely(hw->started == 0 && tx_pkts != hw->inject_pkts))
 		return nb_tx;
@@ -2201,17 +2190,6 @@ virtio_xmit_pkts_inorder(void *tx_queue,
 		struct rte_mbuf *txm = tx_pkts[nb_tx];
 		int slots, need;
 
-		/* Do VLAN tag insertion */
-		if (unlikely(txm->ol_flags & PKT_TX_VLAN_PKT)) {
-			error = rte_vlan_insert(&txm);
-			if (unlikely(error)) {
-				rte_pktmbuf_free(txm);
-				continue;
-			}
-			/* vlan_insert may add a header mbuf */
-			tx_pkts[nb_tx] = txm;
-		}
-
 		/* optimize ring usage */
 		if ((vtpci_with_feature(hw, VIRTIO_F_ANY_LAYOUT) ||
 		     vtpci_with_feature(hw, VIRTIO_F_VERSION_1)) &&
-- 
2.17.1