selftests: drv-net: xdp: Validate single-buff XDP_TX in multi-buff mode

Validate that drivers with multi-buff XDP programs properly reinitialize
xdp_buff between packets.

Signed-off-by: Dimitri Daskalakis <dimitri.daskalakis1@gmail.com>
Link: https://patch.msgid.link/20250821014023.1481662-4-dimitri.daskalakis1@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/tools/testing/selftests/drivers/net/xdp.py b/tools/testing/selftests/drivers/net/xdp.py
index cea24c9b573e9d489470a0dc852819614d99b912..35e9495cd50627843a9581123d3abe953b5c386c 100755 (executable)
--- a/tools/testing/selftests/drivers/net/xdp.py
+++ b/tools/testing/selftests/drivers/net/xdp.py
@@ -358,7 +358,10 @@ def test_xdp_native_tx_mb(cfg):
     """
     bpf_info = BPFProgInfo("xdp_prog_frags", "xdp_native.bpf.o",
                            "xdp.frags", 9000)
-    _test_xdp_native_tx(cfg, bpf_info, [8000])
+    # The first packet ensures we exercise the fragmented code path.
+    # And the subsequent 0-sized packet ensures the driver
+    # reinitializes xdp_buff correctly.
+    _test_xdp_native_tx(cfg, bpf_info, [8000, 0])
 
 
 def _validate_res(res, offset_lst, pkt_sz_lst):