app/testpmd: fix GRO packets flush on timeout

[ upstream commit 461c287ab55303bad1e68bd1dfac6e6ec27953c3 ]

In heavy-weight mode GRO which is based on timer, the GRO packets
will not be flushed in spite of timer expiry if there is no packet
in the current poll.

If timer mode GRO is enabled the rte_gro_timeout_flush API should be
invoked.

Fixes: b7091f1 ("app/testpmd: enable the heavyweight mode TCP/IPv4 GRO")

Signed-off-by: Kumara Parameshwaran <kumaraparamesh92@gmail.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@amd.com>

app/test-pmd/csumonly.c

@@ -867,17 +867,29 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
 	nb_rx = rte_eth_rx_burst(fs->rx_port, fs->rx_queue, pkts_burst,
 				 nb_pkt_per_burst);
 	inc_rx_burst_stats(fs, nb_rx);
-	if (unlikely(nb_rx == 0))
-		return;
+	if (unlikely(nb_rx == 0)) {
+#ifndef RTE_LIB_GRO
+		return ;
+#else
+		gro_enable = gro_ports[fs->rx_port].enable;
+		/*
+		 * Check if packets need to be flushed in the GRO context
+		 * due to a timeout.
+		 *
+		 * Continue only in GRO heavyweight mode and if there are
+		 * packets in the GRO context.
+		 */
+		if (!gro_enable || (gro_flush_cycles == GRO_DEFAULT_FLUSH_CYCLES) ||
+			(rte_gro_get_pkt_count(current_fwd_lcore()->gro_ctx) == 0))
+			return ;
+#endif
+	}
 
 	fs->rx_packets += nb_rx;
 	rx_bad_ip_csum = 0;
 	rx_bad_l4_csum = 0;
 	rx_bad_outer_l4_csum = 0;
 	rx_bad_outer_ip_csum = 0;
-#ifdef RTE_LIB_GRO
-	gro_enable = gro_ports[fs->rx_port].enable;
-#endif
 
 	txp = &ports[fs->tx_port];
 	tx_offloads = txp->dev_conf.txmode.offloads;
@@ -1105,6 +1117,7 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
 	}
 
 #ifdef RTE_LIB_GRO
+	gro_enable = gro_ports[fs->rx_port].enable;
 	if (unlikely(gro_enable)) {
 		if (gro_flush_cycles == GRO_DEFAULT_FLUSH_CYCLES) {
 			nb_rx = rte_gro_reassemble_burst(pkts_burst, nb_rx,