net/iavf: fix TSO with big segments

[ upstream commit 8a1a5327ba71a19d8a6e1b9ceb5563b4af2c2029 ]

Packets to be segmented with TSO are usually larger than MTU.
Plus, a single segment for the whole packet may be used: in OVS case,
an external rte_malloc'd buffer is used for packets received
from vhost-user ports.

Before this fix, TSO packets were dropped by net/iavf with the following
message:
2023-09-18T14:08:52.739Z|00610|dpdk(pmd-c31/id:11)|ERR|iavf_prep_pkts():
	INVALID mbuf: bad data_len=[2962]

Remove the check on data_len.

Fixes: 19ee91c ("net/iavf: check illegal packet sizes")

Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Qi Zhang <qi.z.zhang@intel.com>

drivers/net/iavf/iavf_rxtx.c

@@ -2347,15 +2347,12 @@ iavf_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 
 /* TX prep functions */
 uint16_t
-iavf_prep_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
+iavf_prep_pkts(__rte_unused void *tx_queue, struct rte_mbuf **tx_pkts,
 	      uint16_t nb_pkts)
 {
 	int i, ret;
 	uint64_t ol_flags;
 	struct rte_mbuf *m;
-	struct iavf_tx_queue *txq = tx_queue;
-	struct rte_eth_dev *dev = &rte_eth_devices[txq->port_id];
-	uint16_t max_frame_size = dev->data->mtu + IAVF_ETH_OVERHEAD;
 
 	for (i = 0; i < nb_pkts; i++) {
 		m = tx_pkts[i];
@@ -2379,9 +2376,7 @@ iavf_prep_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
 			return i;
 		}
 
-		/* check the data_len in mbuf */
-		if (m->data_len < IAVF_TX_MIN_PKT_LEN ||
-			m->data_len > max_frame_size) {
+		if (m->pkt_len < IAVF_TX_MIN_PKT_LEN) {
 			rte_errno = EINVAL;
 			return i;
 		}