selftests/bpf: test_xsk: Isolate flaky tests

Some tests are flaky and fail from time to time on virtual interfaces.
Adding them to the CI would trigger lots of 'false' errors.

Remove the flaky tests from the nominal tests table so they won't be
run by the CI in upcoming patch.
Create a flaky_tests table to hold them.
Use this flaky table in xskxceiver.c to keep all the tests available
from the test_xsk.sh script.

Signed-off-by: Bastien Curutchet (eBPF Foundation) <bastien.curutchet@bootlin.com>

Author: bastien-curutchet

tools/testing/selftests/bpf/test_xsk.h

@@ -270,9 +270,6 @@ static const struct test_spec tests[] = {
 	{.name = "XDP_PROG_CLEANUP", .test_func = testapp_xdp_prog_cleanup},
 	{.name = "XDP_DROP_HALF", .test_func = testapp_xdp_drop},
 	{.name = "XDP_SHARED_UMEM", .test_func = testapp_xdp_shared_umem},
-	{.name = "XDP_METADATA_COPY", .test_func = testapp_xdp_metadata},
-	{.name = "XDP_METADATA_COPY_MULTI_BUFF", .test_func = testapp_xdp_metadata_mb},
-	{.name = "SEND_RECEIVE_9K_PACKETS", .test_func = testapp_send_receive_mb},
 	{.name = "SEND_RECEIVE_UNALIGNED_9K_PACKETS",
 	 .test_func = testapp_send_receive_unaligned_mb},
 	{.name = "ALIGNED_INV_DESC_MULTI_BUFF", .test_func = testapp_aligned_inv_desc_mb},
@@ -282,9 +279,16 @@ static const struct test_spec tests[] = {
 	{.name = "HW_SW_MAX_RING_SIZE", .test_func = testapp_hw_sw_max_ring_size},
 	{.name = "XDP_ADJUST_TAIL_SHRINK", .test_func = testapp_adjust_tail_shrink},
 	{.name = "XDP_ADJUST_TAIL_SHRINK_MULTI_BUFF", .test_func = testapp_adjust_tail_shrink_mb},
-	{.name = "XDP_ADJUST_TAIL_GROW", .test_func = testapp_adjust_tail_grow},
 	{.name = "XDP_ADJUST_TAIL_GROW_MULTI_BUFF", .test_func = testapp_adjust_tail_grow_mb},
 	{.name = "TX_QUEUE_CONSUMER", .test_func = testapp_tx_queue_consumer},
 	};
 
+static const struct test_spec flaky_tests[] = {
+	{.name = "XDP_ADJUST_TAIL_GROW", .test_func = testapp_adjust_tail_grow},
+	{.name = "XDP_METADATA_COPY", .test_func = testapp_xdp_metadata},
+	{.name = "XDP_METADATA_COPY_MULTI_BUFF", .test_func = testapp_xdp_metadata_mb},
+	{.name = "SEND_RECEIVE_9K_PACKETS", .test_func = testapp_send_receive_mb},
+};
+
+
 #endif				/* TEST_XSK_H_ */

tools/testing/selftests/bpf/xskxceiver.c

@@ -311,10 +311,14 @@ static void print_tests(void)
 	printf("Tests:\n");
 	for (i = 0; i < ARRAY_SIZE(tests); i++)
 		printf("%u: %s\n", i, tests[i].name);
+	printf("== Flaky tests:\n");
+	for (i = ARRAY_SIZE(tests); i < ARRAY_SIZE(tests) + ARRAY_SIZE(flaky_tests); i++)
+		printf("%u: %s\n", i, flaky_tests[i - ARRAY_SIZE(tests)].name);
 }
 
 int main(int argc, char **argv)
 {
+	const size_t total_tests = ARRAY_SIZE(tests) + ARRAY_SIZE(flaky_tests);
 	struct pkt_stream *rx_pkt_stream_default;
 	struct pkt_stream *tx_pkt_stream_default;
 	struct ifobject *ifobj_tx, *ifobj_rx;
@@ -342,7 +346,7 @@ int main(int argc, char **argv)
 		print_tests();
 		ksft_exit_xpass();
 	}
-	if (opt_run_test != RUN_ALL_TESTS && opt_run_test >= ARRAY_SIZE(tests)) {
+	if (opt_run_test != RUN_ALL_TESTS && opt_run_test >= total_tests) {
 		ksft_print_msg("Error: test %u does not exist.\n", opt_run_test);
 		ksft_exit_xfail();
 	}
@@ -382,7 +386,7 @@ int main(int argc, char **argv)
 	test.rx_pkt_stream_default = rx_pkt_stream_default;
 
 	if (opt_run_test == RUN_ALL_TESTS)
-		nb_tests = ARRAY_SIZE(tests);
+		nb_tests = total_tests;
 	else
 		nb_tests = 1;
 	if (opt_mode == TEST_MODE_ALL) {
@@ -404,11 +408,15 @@ int main(int argc, char **argv)
 		if (opt_mode != TEST_MODE_ALL && i != opt_mode)
 			continue;
 
-		for (j = 0; j < ARRAY_SIZE(tests); j++) {
+		for (j = 0; j < total_tests; j++) {
 			if (opt_run_test != RUN_ALL_TESTS && j != opt_run_test)
 				continue;
 
-			test_init(&test, ifobj_tx, ifobj_rx, i, &tests[j]);
+			if (j < ARRAY_SIZE(tests))
+				test_init(&test, ifobj_tx, ifobj_rx, i, &tests[j]);
+			else
+				test_init(&test, ifobj_tx, ifobj_rx, i,
+					  &flaky_tests[j - ARRAY_SIZE(tests)]);
 			run_pkt_test(&test);
 			usleep(USLEEP_MAX);