[Devel] [PATCH hci-8.1 v2 3/3] selftests: drv-net: read the channel count over netlink

[Eva Kurchatova]

napi_threaded.py asks ethtool for the channel count as JSON, which
ethtool 6.11 cannot print for -l:

  ethtool: bad command line argument(s)
  JSON output not available for this subcommand

  not ok 1 napi_threaded.napi_init

Read the count over ethtool netlink instead, so the test does not
depend on the ethtool version installed.

https://virtuozzo.atlassian.net/browse/VSTOR-139651
Feature: fix selftests
Signed-off-by: Eva Kurchatova <eva.kurchatova at virtuozzo.com>
---
 tools/testing/selftests/drivers/net/napi_threaded.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/napi_threaded.py b/tools/testing/selftests/drivers/net/napi_threaded.py
index ed66efa481b0..33cc3f8752d3 100755
--- a/tools/testing/selftests/drivers/net/napi_threaded.py
+++ b/tools/testing/selftests/drivers/net/napi_threaded.py
@@ -7,7 +7,7 @@ Test napi threaded states.
 
 from lib.py import ksft_run, ksft_exit
 from lib.py import ksft_eq, ksft_ne, ksft_ge
-from lib.py import NetDrvEnv, NetdevFamily
+from lib.py import EthtoolFamily, NetDrvEnv, NetdevFamily
 from lib.py import cmd, defer, ethtool
 
 
@@ -28,7 +28,9 @@ def _set_threaded_state(cfg, threaded) -> None:
 
 
 def _setup_deferred_cleanup(cfg) -> None:
-    combined = ethtool(f"-l {cfg.ifname}", json=True)[0].get("combined", 0)
+    # Not every ethtool prints -l as JSON, ask the kernel
+    chan = EthtoolFamily().channels_get({'header': {'dev-index': cfg.ifindex}})
+    combined = chan.get('combined-count', 0)
     ksft_ge(combined, 2)
     defer(ethtool, f"-L {cfg.ifname} combined {combined}")
 
-- 
2.55.0