[PATCH bpf v3 5/6] selftests/bpf: Fix error failure of case test_xdp_adjust_tail_grow

[Xu Kuohai]

test_xdp_adjust_tail_grow failed with ipv6:
  test_xdp_adjust_tail_grow:FAIL:ipv6 unexpected error: -28 (errno 28)

The reason is that this test case tests ipv4 before ipv6, and when ipv4
test finished, topts.data_size_out was set to 54, which is smaller than the
ipv6 output data size 114, so ipv6 test fails with NOSPC error.

Fix it by reset topts.data_size_out to sizeof(buf) before testing ipv6.

Fixes: 04fcb5f9a104 ("selftests/bpf: Migrate from bpf_prog_test_run")
Signed-off-by: Xu Kuohai <xukuohai@xxxxxxxxxx>
---
 tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
index 9b9cf8458adf..009ee37607df 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
@@ -63,6 +63,7 @@ static void test_xdp_adjust_tail_grow(void)
 	expect_sz = sizeof(pkt_v6) + 40; /* Test grow with 40 bytes */
 	topts.data_in = &pkt_v6;
 	topts.data_size_in = sizeof(pkt_v6);
+	topts.data_size_out = sizeof(buf);
 	err = bpf_prog_test_run_opts(prog_fd, &topts);
 	ASSERT_OK(err, "ipv6");
 	ASSERT_EQ(topts.retval, XDP_TX, "ipv6 retval");
-- 
2.30.2