[PATCH net-next v3 5/5] selftests: drv-net: Request larger zcrx buffers

["Björn Töpel" <bjorn@kernel.org>]

The large-chunk test always requests two base pages. On interfaces with
a large MTU, that may not exceed two maximum-sized frames.

Request a power-of-two buffer larger than twice the MTU. This makes the
existing rx_buf_len check and data-integrity traffic exercise the larger
layout.

Signed-off-by: Björn Töpel <bjorn@kernel.org>
---
 tools/testing/selftests/drivers/net/hw/iou-zcrx.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/drivers/net/hw/iou-zcrx.py b/tools/testing/selftests/drivers/net/hw/iou-zcrx.py
index c833535d8a03..5047fdb56005 100755
--- a/tools/testing/selftests/drivers/net/hw/iou-zcrx.py
+++ b/tools/testing/selftests/drivers/net/hw/iou-zcrx.py
@@ -221,9 +221,13 @@ def test_zcrx_large_chunks(cfg) -> None:
 
     single(cfg)
     page_size = resource.getpagesize()
+    mtu = cfg.dev["mtu"]
     nr_pages = 2
+    while nr_pages * page_size <= 2 * mtu:
+        nr_pages *= 2
     rx_buf_len = nr_pages * page_size
-    rx_cmd = f"{cfg.bin_local} -s -p {cfg.port} -i {cfg.ifname} -q {cfg.target} -x {nr_pages}"
+    rx_cmd = (f"{cfg.bin_local} -s -p {cfg.port} -i {cfg.ifname} "
+              f"-q {cfg.target} -x {nr_pages}")
     tx_cmd = f"{cfg.bin_remote} -c -h {cfg.addr_v['6']} -p {cfg.port} -l 12840"
 
     probe = cmd(rx_cmd + " -d", fail=False)
-- 
2.55.0