selftests/xsk: add option that lists all tests

Add a command line option (-l) that lists all the tests. The number
before the test will be used in the next commit for specifying a
single test to run. Here is an example of the output:

Tests:
0: SEND_RECEIVE
1: SEND_RECEIVE_2K_FRAME
2: SEND_RECEIVE_SINGLE_PKT
3: POLL_RX
4: POLL_TX
5: POLL_RXQ_FULL
6: POLL_TXQ_FULL
7: SEND_RECEIVE_UNALIGNED
:
:

Signed-off-by: Magnus Karlsson <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexei Starovoitov <[e-mail]>

tools/testing/selftests/bpf/test_xsk.sh

···
 #
 # Run test suite in a specific mode only [skb,drv,zc]
 #   sudo ./test_xsk.sh -m MODE
+#
+# List available tests
+#   ./test_xsk.sh -l
 
 . xsk_prereqs.sh
 
 ETH=""
 
-while getopts "vi:dm:" flag
+while getopts "vi:dm:l" flag
 do
 	case "${flag}" in
 		v) verbose=1;;
 		d) debug=1;;
 		i) ETH=${OPTARG};;
 		m) MODE=${OPTARG};;
+		l) list=1;;
 	esac
 done
 
···
 	ip link set ${VETH0} up
 }
 
+if [[ $list -eq 1 ]]; then
+        ./${XSKOBJ} -l
+        exit
+fi
+
 if [ ! -z $ETH ]; then
 	VETH0=${ETH}
 	VETH1=${ETH}
···
 	cleanup_exit ${VETH0} ${VETH1}
 else
 	cleanup_iface ${ETH} ${MTU}
+fi
+
+if [[ $list -eq 1 ]]; then
+    exit
 fi
 
 TEST_NAME="XSK_SELFTESTS_${VETH0}_BUSY_POLL"

tools/testing/selftests/bpf/xsk_prereqs.sh

···
 	fi
 
 	./${XSKOBJ} -i ${VETH0} -i ${VETH1} ${ARGS}
-
 	retval=$?
-	test_status $retval "${TEST_NAME}"
-	statusList+=($retval)
-	nameList+=(${TEST_NAME})
+
+	if [[ $list -ne 1 ]]; then
+	    test_status $retval "${TEST_NAME}"
+	    statusList+=($retval)
+	    nameList+=(${TEST_NAME})
+	fi
 }

tools/testing/selftests/bpf/xskxceiver.c

···
 static const char *MAC2 = "\x00\x0A\x56\x9E\xEE\x61";
 
 static bool opt_verbose;
+static bool opt_print_tests;
 static enum test_mode opt_mode = TEST_MODE_ALL;
 
 static void __exit_with_error(int error, const char *file, const char *func, int line)
···
 	{"busy-poll", no_argument, 0, 'b'},
 	{"verbose", no_argument, 0, 'v'},
 	{"mode", required_argument, 0, 'm'},
+	{"list", no_argument, 0, 'l'},
 	{0, 0, 0, 0}
 };
 
···
 		"  -i, --interface      Use interface\n"
 		"  -v, --verbose        Verbose output\n"
 		"  -b, --busy-poll      Enable busy poll\n"
-		"  -m, --mode           Run only mode skb, drv, or zc\n";
+		"  -m, --mode           Run only mode skb, drv, or zc\n"
+		"  -l, --list           List all available tests\n";
 
 	ksft_print_msg(str, prog);
 }
···
 	opterr = 0;
 
 	for (;;) {
-		c = getopt_long(argc, argv, "i:vbm:", long_options, &option_index);
+		c = getopt_long(argc, argv, "i:vbm:l", long_options, &option_index);
 		if (c == -1)
 			break;
 
···
 				usage(basename(argv[0]));
 				ksft_exit_xfail();
 			}
+			break;
+		case 'l':
+			opt_print_tests = true;
 			break;
 		default:
 			usage(basename(argv[0]));
···
 	{.name = "TOO_MANY_FRAGS", .test_func = testapp_too_many_frags},
 };
 
+static void print_tests(void)
+{
+	u32 i;
+
+	printf("Tests:\n");
+	for (i = 0; i < ARRAY_SIZE(tests); i++)
+		printf("%u: %s\n", i, tests[i].name);
+}
+
 int main(int argc, char **argv)
 {
 	struct pkt_stream *rx_pkt_stream_default;
···
 	setlocale(LC_ALL, "");
 
 	parse_command_line(ifobj_tx, ifobj_rx, argc, argv);
+
+	if (opt_print_tests) {
+		print_tests();
+		ksft_exit_xpass();
+	}
 
 	shared_netdev = (ifobj_tx->ifindex == ifobj_rx->ifindex);
 	ifobj_tx->shared_umem = shared_netdev;