selftests: drv-net: fix linter warnings in pp_alloc_fail

Fix linter warnings, it's a bit hard to check for new ones otherwise.

  W0311: Bad indentation. Found 16 spaces, expected 12 (bad-indentation)
  C0114: Missing module docstring (missing-module-docstring)
  W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
  C0116: Missing function or method docstring (missing-function-docstring)

Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20251007232653.2099376-8-kuba@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: kuba-moo

tools/testing/selftests/drivers/net/hw/pp_alloc_fail.py

@@ -1,6 +1,10 @@
 #!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0
 
+"""
+Test driver resilience vs page pool allocation failures.
+"""
+
 import errno
 import time
 import os
@@ -13,7 +17,8 @@
 
 def _write_fail_config(config):
     for key, value in config.items():
-        with open("/sys/kernel/debug/fail_function/" + key, "w") as fp:
+        path = "/sys/kernel/debug/fail_function/"
+        with open(path + key, "w", encoding='ascii') as fp:
             fp.write(str(value) + "\n")
 
 
@@ -22,8 +27,7 @@ def _enable_pp_allocation_fail():
         raise KsftSkipEx("Kernel built without function error injection (or DebugFS)")
 
     if not os.path.exists("/sys/kernel/debug/fail_function/page_pool_alloc_netmems"):
-        with open("/sys/kernel/debug/fail_function/inject", "w") as fp:
-            fp.write("page_pool_alloc_netmems\n")
+        _write_fail_config({"inject": "page_pool_alloc_netmems"})
 
     _write_fail_config({
         "verbose": 0,
@@ -38,8 +42,7 @@ def _disable_pp_allocation_fail():
         return
 
     if os.path.exists("/sys/kernel/debug/fail_function/page_pool_alloc_netmems"):
-        with open("/sys/kernel/debug/fail_function/inject", "w") as fp:
-            fp.write("\n")
+        _write_fail_config({"inject": ""})
 
     _write_fail_config({
         "probability": 0,
@@ -48,6 +51,10 @@ def _disable_pp_allocation_fail():
 
 
 def test_pp_alloc(cfg, netdevnl):
+    """
+    Configure page pool allocation fail injection while traffic is running.
+    """
+
     def get_stats():
         return netdevnl.qstats_get({"ifindex": cfg.ifindex}, dump=True)[0]
 
@@ -105,7 +112,7 @@ def check_traffic_flowing():
             else:
                 ksft_pr("ethtool -G change retval: did not succeed", new_g)
         else:
-                ksft_pr("ethtool -G change retval: did not try")
+            ksft_pr("ethtool -G change retval: did not try")
 
         time.sleep(0.1)
         check_traffic_flowing()
@@ -119,6 +126,7 @@ def check_traffic_flowing():
 
 
 def main() -> None:
+    """ Ksft boiler plate main """
     netdevnl = NetdevFamily()
     with NetDrvEpEnv(__file__, nsim_test=False) as cfg: