selftests: xsk: Validate tx stats on tx thread

Validate the tx stats on the Tx thread instead of the Rx
thread. Depending on your settings, you might not be allowed to query
the statistics of a socket you do not own, so better to do this on the
correct thread to start with.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825093722.10219-11-magnus.karlsson@gmail.com

tools/testing/selftests/bpf/xdpxceiver.c

@@ -642,23 +642,22 @@ static void tx_only_all(struct ifobject *ifobject)
 	complete_tx_only_all(ifobject);
 }
 
-static void stats_validate(struct ifobject *ifobject)
+static bool rx_stats_are_valid(struct ifobject *ifobject)
 {
+	u32 xsk_stat = 0, expected_stat = opt_pkt_count;
+	struct xsk_socket *xsk = ifobject->xsk->xsk;
+	int fd = xsk_socket__fd(xsk);
 	struct xdp_statistics stats;
 	socklen_t optlen;
 	int err;
-	struct xsk_socket *xsk = stat_test_type == STAT_TEST_TX_INVALID ?
-							ifdict[!ifobject->ifdict_index]->xsk->xsk :
-							ifobject->xsk->xsk;
-	int fd = xsk_socket__fd(xsk);
-	unsigned long xsk_stat = 0, expected_stat = opt_pkt_count;
-
-	sigvar = 0;
 
 	optlen = sizeof(stats);
 	err = getsockopt(fd, SOL_XDP, XDP_STATISTICS, &stats, &optlen);
-	if (err)
-		return;
+	if (err) {
+		ksft_test_result_fail("ERROR: [%s] getsockopt(XDP_STATISTICS) error %u %s\n",
+				      __func__, -err, strerror(-err));
+		return true;
+	}
 
 	if (optlen == sizeof(struct xdp_statistics)) {
 		switch (stat_test_type) {
@@ -666,8 +665,7 @@ static void stats_validate(struct ifobject *ifobject)
 			xsk_stat = stats.rx_dropped;
 			break;
 		case STAT_TEST_TX_INVALID:
-			xsk_stat = stats.tx_invalid_descs;
-			break;
+			return true;
 		case STAT_TEST_RX_FULL:
 			xsk_stat = stats.rx_ring_full;
 			expected_stat -= RX_FULL_RXQSIZE;
@@ -680,8 +678,33 @@ static void stats_validate(struct ifobject *ifobject)
 		}
 
 		if (xsk_stat == expected_stat)
-			sigvar = 1;
+			return true;
+	}
+
+	return false;
+}
+
+static void tx_stats_validate(struct ifobject *ifobject)
+{
+	struct xsk_socket *xsk = ifobject->xsk->xsk;
+	int fd = xsk_socket__fd(xsk);
+	struct xdp_statistics stats;
+	socklen_t optlen;
+	int err;
+
+	optlen = sizeof(stats);
+	err = getsockopt(fd, SOL_XDP, XDP_STATISTICS, &stats, &optlen);
+	if (err) {
+		ksft_test_result_fail("ERROR: [%s] getsockopt(XDP_STATISTICS) error %u %s\n",
+				      __func__, -err, strerror(-err));
+		return;
 	}
+
+	if (stats.tx_invalid_descs == opt_pkt_count)
+		return;
+
+	ksft_test_result_fail("ERROR: [%s] tx_invalid_descs incorrect. Got [%u] expected [%u]\n",
+			      __func__, stats.tx_invalid_descs, opt_pkt_count);
 }
 
 static void thread_common_ops(struct ifobject *ifobject, void *bufs)
@@ -767,6 +790,9 @@ static void *worker_testapp_validate_tx(void *arg)
 	print_verbose("Sending %d packets on interface %s\n", opt_pkt_count, ifobject->ifname);
 	tx_only_all(ifobject);
 
+	if (stat_test_type == STAT_TEST_TX_INVALID)
+		tx_stats_validate(ifobject);
+
 	testapp_cleanup_xsk_res(ifobject);
 	pthread_exit(NULL);
 }
@@ -792,7 +818,8 @@ static void *worker_testapp_validate_rx(void *arg)
 		if (test_type != TEST_TYPE_STATS) {
 			rx_pkt(ifobject->xsk, fds);
 		} else {
-			stats_validate(ifobject);
+			if (rx_stats_are_valid(ifobject))
+				break;
 		}
 		if (sigvar)
 			break;