Merge branch 'fix-wrong-hds-thresh-value-setting'

Taehee Yoo says:

====================
fix wrong hds-thresh value setting

A hds-thresh value is not set correctly if input value is 0.
The cause is that ethtool_ringparam_get_cfg(), which is a internal
function that returns ringparameters from both ->get_ringparam() and
dev->cfg can't return a correct hds-thresh value.

The first patch fixes ethtool_ringparam_get_cfg() to set hds-thresh
value correcltly.

The second patch adds random test for hds-thresh value.
So that we can test 0 value for a hds-thresh properly.
====================

Link: https://patch.msgid.link/20250404122126.1555648-1-ap420073@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/ethtool/common.c

@@ -830,6 +830,7 @@ void ethtool_ringparam_get_cfg(struct net_device *dev,
 
 	/* Driver gives us current state, we want to return current config */
 	kparam->tcp_data_split = dev->cfg->hds_config;
+	kparam->hds_thresh = dev->cfg->hds_thresh;
 }
 
 static void ethtool_init_tsinfo(struct kernel_ethtool_ts_info *info)

tools/testing/selftests/drivers/net/hds.py

@@ -6,7 +6,7 @@
 from lib.py import ksft_run, ksft_exit, ksft_eq, ksft_raises, KsftSkipEx
 from lib.py import CmdExitFailure, EthtoolFamily, NlError
 from lib.py import NetDrvEnv
-from lib.py import defer, ethtool, ip
+from lib.py import defer, ethtool, ip, random
 
 
 def _get_hds_mode(cfg, netnl) -> str:
@@ -109,6 +109,36 @@ def set_hds_thresh_zero(cfg, netnl) -> None:
 
     ksft_eq(0, rings['hds-thresh'])
 
+def set_hds_thresh_random(cfg, netnl) -> None:
+    try:
+        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
+    except NlError as e:
+        raise KsftSkipEx('ring-get not supported by device')
+    if 'hds-thresh' not in rings:
+        raise KsftSkipEx('hds-thresh not supported by device')
+    if 'hds-thresh-max' not in rings:
+        raise KsftSkipEx('hds-thresh-max not defined by device')
+
+    if rings['hds-thresh-max'] < 2:
+        raise KsftSkipEx('hds-thresh-max is too small')
+    elif rings['hds-thresh-max'] == 2:
+        hds_thresh = 1
+    else:
+        while True:
+            hds_thresh = random.randint(1, rings['hds-thresh-max'] - 1)
+            if hds_thresh != rings['hds-thresh']:
+                break
+
+    try:
+        netnl.rings_set({'header': {'dev-index': cfg.ifindex}, 'hds-thresh': hds_thresh})
+    except NlError as e:
+        if e.error == errno.EINVAL:
+            raise KsftSkipEx("hds-thresh-set not supported by the device")
+        elif e.error == errno.EOPNOTSUPP:
+            raise KsftSkipEx("ring-set not supported by the device")
+    rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
+    ksft_eq(hds_thresh, rings['hds-thresh'])
+
 def set_hds_thresh_max(cfg, netnl) -> None:
     try:
         rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
@@ -243,6 +273,7 @@ def main() -> None:
                   get_hds_thresh,
                   set_hds_disable,
                   set_hds_enable,
+                  set_hds_thresh_random,
                   set_hds_thresh_zero,
                   set_hds_thresh_max,
                   set_hds_thresh_gt,