[PATCH net v2 5/6] selftests: drv-net: Move _set_ethtool_feat() into lib

From: Ovidiu Panait

Date: Fri Aug 21 2026 - 13:20:01 EST


Move the _set_ethtool_feat() helper from gro.py into lib, so that it can
be reused by the VLAN test added in the next commit. Drop the leading
underscore, now that the helper is exported.

Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@xxxxxxxxxxx>
---
v2 changes:
- New patch.

tools/testing/selftests/drivers/net/gro.py | 65 ++++++-------------
.../selftests/drivers/net/lib/py/__init__.py | 3 +-
.../selftests/drivers/net/lib/py/feat.py | 37 +++++++++++
3 files changed, 59 insertions(+), 46 deletions(-)
create mode 100644 tools/testing/selftests/drivers/net/lib/py/feat.py

diff --git a/tools/testing/selftests/drivers/net/gro.py b/tools/testing/selftests/drivers/net/gro.py
index 6ab8c97880d1..051a3b2d0ead 100755
--- a/tools/testing/selftests/drivers/net/gro.py
+++ b/tools/testing/selftests/drivers/net/gro.py
@@ -42,7 +42,7 @@ import re
from lib.py import ksft_run, ksft_exit, ksft_pr
from lib.py import NetDrvEpEnv, KsftFailEx, KsftXfailEx
from lib.py import NetdevFamily, EthtoolFamily
-from lib.py import bkg, cmd, defer, ethtool, ip
+from lib.py import bkg, cmd, defer, ethtool, ip, set_ethtool_feat
from lib.py import ksft_variants, KsftNamedVariant


@@ -96,31 +96,6 @@ def _set_mtu_restore(dev, mtu, host):
defer(ip, f"link set dev {dev['ifname']} mtu {dev['mtu']}", host=host)


-def _set_ethtool_feat(dev, current, feats, host=None):
- s2n = {True: "on", False: "off"}
-
- new = ["-K", dev]
- old = ["-K", dev]
- no_change = True
- for name, state in feats.items():
- new += [name, s2n[state]]
- old += [name, s2n[current[name]["active"]]]
-
- if current[name]["active"] != state:
- no_change = False
- if current[name]["fixed"]:
- raise KsftXfailEx(f"Device does not support {name}")
- if no_change:
- return
-
- eth_cmd = ethtool(" ".join(new), host=host)
- defer(ethtool, " ".join(old), host=host)
-
- # If ethtool printed something kernel must have modified some features
- if eth_cmd.stdout:
- ksft_pr(eth_cmd)
-
-
def _get_queue_stats(cfg, queue_id):
"""Get stats for a specific Rx queue."""
cfg.wait_hw_stats_settle()
@@ -247,15 +222,15 @@ def _setup(cfg, mode, test_name):
_write_defer_restore(cfg, flush_path, "200000", defer_undo=True)
_write_defer_restore(cfg, irq_path, "10", defer_undo=True)

- _set_ethtool_feat(cfg.ifname, cfg.feat,
- {"generic-receive-offload": True,
- "rx-gro-hw": False,
- "large-receive-offload": False})
+ set_ethtool_feat(cfg.ifname, cfg.feat,
+ {"generic-receive-offload": True,
+ "rx-gro-hw": False,
+ "large-receive-offload": False})
elif mode == "hw":
- _set_ethtool_feat(cfg.ifname, cfg.feat,
- {"generic-receive-offload": False,
- "rx-gro-hw": True,
- "large-receive-offload": False})
+ set_ethtool_feat(cfg.ifname, cfg.feat,
+ {"generic-receive-offload": False,
+ "rx-gro-hw": True,
+ "large-receive-offload": False})

# Some NICs treat HW GRO as a GRO sub-feature so disabling GRO
# will also clear HW GRO. Use a hack of installing XDP generic
@@ -270,27 +245,27 @@ def _setup(cfg, mode, test_name):
# Attaching XDP may change features, fetch the latest state
feat = ethtool(f"-k {cfg.ifname}", json=True)[0]

- _set_ethtool_feat(cfg.ifname, feat,
- {"generic-receive-offload": True,
- "rx-gro-hw": True,
- "large-receive-offload": False})
+ set_ethtool_feat(cfg.ifname, feat,
+ {"generic-receive-offload": True,
+ "rx-gro-hw": True,
+ "large-receive-offload": False})
elif mode == "lro":
# netdevsim advertises LRO for feature inheritance testing with
# bonding/team tests but it doesn't actually perform the offload
cfg.require_nsim(nsim_test=False)

- _set_ethtool_feat(cfg.ifname, cfg.feat,
- {"generic-receive-offload": False,
- "rx-gro-hw": False,
- "large-receive-offload": True})
+ set_ethtool_feat(cfg.ifname, cfg.feat,
+ {"generic-receive-offload": False,
+ "rx-gro-hw": False,
+ "large-receive-offload": True})

try:
# Disable TSO for local tests
cfg.require_nsim() # will raise KsftXfailEx if not running on nsim

- _set_ethtool_feat(cfg.remote_ifname, cfg.remote_feat,
- {"tcp-segmentation-offload": False},
- host=cfg.remote)
+ set_ethtool_feat(cfg.remote_ifname, cfg.remote_feat,
+ {"tcp-segmentation-offload": False},
+ host=cfg.remote)
except KsftXfailEx:
pass

diff --git a/tools/testing/selftests/drivers/net/lib/py/__init__.py b/tools/testing/selftests/drivers/net/lib/py/__init__.py
index ee903bcf3207..c261aac2b976 100644
--- a/tools/testing/selftests/drivers/net/lib/py/__init__.py
+++ b/tools/testing/selftests/drivers/net/lib/py/__init__.py
@@ -48,11 +48,12 @@ try:
"ksft_not_none", "ksft_not_none"]

from .env import NetDrvEnv, NetDrvEpEnv, NetDrvContEnv
+ from .feat import set_ethtool_feat
from .load import GenerateTraffic, Iperf3Runner
from .remote import Remote

__all__ += ["NetDrvEnv", "NetDrvEpEnv", "NetDrvContEnv", "GenerateTraffic",
- "Remote", "Iperf3Runner"]
+ "Remote", "Iperf3Runner", "set_ethtool_feat"]
except ModuleNotFoundError as e:
print("Failed importing `net` library from kernel sources")
print(str(e))
diff --git a/tools/testing/selftests/drivers/net/lib/py/feat.py b/tools/testing/selftests/drivers/net/lib/py/feat.py
new file mode 100644
index 000000000000..33b4895059df
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/lib/py/feat.py
@@ -0,0 +1,37 @@
+# SPDX-License-Identifier: GPL-2.0
+
+"""
+Netdev feature helper utilities for kernel selftests.
+
+Provides common operations for changing device features via ethtool,
+used by driver test files.
+"""
+
+from lib.py import KsftXfailEx
+from lib.py import ksft_pr
+from lib.py import defer, ethtool
+
+
+def set_ethtool_feat(dev, current, feats, host=None):
+ s2n = {True: "on", False: "off"}
+
+ new = ["-K", dev]
+ old = ["-K", dev]
+ no_change = True
+ for name, state in feats.items():
+ new += [name, s2n[state]]
+ old += [name, s2n[current[name]["active"]]]
+
+ if current[name]["active"] != state:
+ no_change = False
+ if current[name]["fixed"]:
+ raise KsftXfailEx(f"Device does not support {name}")
+ if no_change:
+ return
+
+ eth_cmd = ethtool(" ".join(new), host=host)
+ defer(ethtool, " ".join(old), host=host)
+
+ # If ethtool printed something kernel must have modified some features
+ if eth_cmd.stdout:
+ ksft_pr(eth_cmd)
--
2.34.1