examples/multi_process: fix client crash with sparse ports

The mp_client crashes if run on Azure or any system where ethdev
ports are owned. In that case, the tx_buffer and tx_stats for the
real port were initialized correctly, but the wrong port was used.

For example if the server has Ports 3 and 5. Then calling
rte_eth_tx_buffer_flush on any other buffer will dereference null
because the tx buffer for that port was not allocated.

Also:
   - the flush code is common enough that it should not be marked
     unlikely
   - combine conditions to reduce indentation
   - avoid unnecessary if() if sent is zero.

Fixes: e2366e74e029 ("examples: use buffered Tx")
Cc: stable@dpdk.org
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Acked-by: Matan Azrad <matan@mellanox.com>

diff --git a/examples/multi_process/client_server_mp/mp_client/client.c b/examples/multi_process/client_server_mp/mp_client/client.c
index c23dd3f..361d90b 100644 (file)
--- a/examples/multi_process/client_server_mp/mp_client/client.c
+++ b/examples/multi_process/client_server_mp/mp_client/client.c
@@ -246,19 +246,19 @@ main(int argc, char *argv[])
 
        for (;;) {
                uint16_t i, rx_pkts;
-               uint16_t port;
 
                rx_pkts = rte_ring_dequeue_burst(rx_ring, pkts,
                                PKT_READ_SIZE, NULL);
 
-               if (unlikely(rx_pkts == 0)){
-                       if (need_flush)
-                               for (port = 0; port < ports->num_ports; port++) {
-                                       sent = rte_eth_tx_buffer_flush(ports->id[port], client_id,
-                                                       tx_buffer[port]);
-                                       if (unlikely(sent))
-                                               tx_stats->tx[port] += sent;
-                               }
+               if (rx_pkts == 0 && need_flush) {
+                       for (i = 0; i < ports->num_ports; i++) {
+                               uint16_t port = ports->id[i];
+
+                               sent = rte_eth_tx_buffer_flush(port,
+                                                              client_id,
+                                                              tx_buffer[port]);
+                               tx_stats->tx[port] += sent;
+                       }
                        need_flush = 0;
                        continue;
                }