From: Jakub Kicinski <kuba@kernel.org>
Date: Wed, 18 Jun 2025 20:38:23 +0000 (-0700)
Subject: net: ethtool: don't mux RXFH via rxnfc callbacks
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=72792461c8e8d19b3fe8d62a1b3ea6a2e3135182;p=thirdparty%2Fkernel%2Fstable.git

net: ethtool: don't mux RXFH via rxnfc callbacks

All drivers have been converted. Stop using the rxnfc fallbacks
for Rx Flow Hashing configuration.

Joe pointed out in earlier review that in ethtool_set_rxfh()
we need both .get_rxnfc and .get_rxfh_fields, because we need
both the ring count and flow hashing (because we call
ethtool_check_flow_types()). IOW the existing check added
for transitioning drivers was buggy.

Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250618203823.1336156-11-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index a14cf901c32d..82cde640aa87 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -1037,33 +1037,21 @@ static int ethtool_check_xfrm_rxfh(u32 input_xfrm, u64 rxfh)
 static int ethtool_check_flow_types(struct net_device *dev, u32 input_xfrm)
 {
 	const struct ethtool_ops *ops = dev->ethtool_ops;
-	struct ethtool_rxnfc info = {
-		.cmd = ETHTOOL_GRXFH,
-	};
 	int err;
 	u32 i;
 
 	for (i = 0; i < __FLOW_TYPE_COUNT; i++) {
+		struct ethtool_rxfh_fields fields = {
+			.flow_type	= i,
+		};
+
 		if (!flow_type_hashable(i))
 			continue;
 
-		info.flow_type = i;
-
-		if (ops->get_rxfh_fields) {
-			struct ethtool_rxfh_fields fields = {
-				.flow_type	= info.flow_type,
-			};
-
-			if (ops->get_rxfh_fields(dev, &fields))
-				continue;
-
-			info.data = fields.data;
-		} else {
-			if (ops->get_rxnfc(dev, &info, NULL))
-				continue;
-		}
+		if (ops->get_rxfh_fields(dev, &fields))
+			continue;
 
-		err = ethtool_check_xfrm_rxfh(input_xfrm, info.data);
+		err = ethtool_check_xfrm_rxfh(input_xfrm, fields.data);
 		if (err)
 			return err;
 	}
@@ -1080,7 +1068,7 @@ ethtool_set_rxfh_fields(struct net_device *dev, u32 cmd, void __user *useraddr)
 	size_t info_size = sizeof(info);
 	int rc;
 
-	if (!ops->set_rxnfc && !ops->set_rxfh_fields)
+	if (!ops->set_rxfh_fields)
 		return -EOPNOTSUPP;
 
 	rc = ethtool_rxnfc_copy_struct(cmd, &info, &info_size, useraddr);
@@ -1103,9 +1091,6 @@ ethtool_set_rxfh_fields(struct net_device *dev, u32 cmd, void __user *useraddr)
 			return rc;
 	}
 
-	if (!ops->set_rxfh_fields)
-		return ops->set_rxnfc(dev, &info);
-
 	fields.data = info.data;
 	fields.flow_type = info.flow_type & ~FLOW_RSS;
 	if (info.flow_type & FLOW_RSS)
@@ -1120,9 +1105,10 @@ ethtool_get_rxfh_fields(struct net_device *dev, u32 cmd, void __user *useraddr)
 	struct ethtool_rxnfc info;
 	size_t info_size = sizeof(info);
 	const struct ethtool_ops *ops = dev->ethtool_ops;
+	struct ethtool_rxfh_fields fields = {};
 	int ret;
 
-	if (!ops->get_rxnfc && !ops->get_rxfh_fields)
+	if (!ops->get_rxfh_fields)
 		return -EOPNOTSUPP;
 
 	ret = ethtool_rxnfc_copy_struct(cmd, &info, &info_size, useraddr);
@@ -1133,24 +1119,15 @@ ethtool_get_rxfh_fields(struct net_device *dev, u32 cmd, void __user *useraddr)
 	    !ops->rxfh_per_ctx_fields)
 		return -EINVAL;
 
-	if (ops->get_rxfh_fields) {
-		struct ethtool_rxfh_fields fields = {
-			.flow_type	= info.flow_type & ~FLOW_RSS,
-		};
-
-		if (info.flow_type & FLOW_RSS)
-			fields.rss_context = info.rss_context;
+	fields.flow_type = info.flow_type & ~FLOW_RSS;
+	if (info.flow_type & FLOW_RSS)
+		fields.rss_context = info.rss_context;
 
-		ret = ops->get_rxfh_fields(dev, &fields);
-		if (ret < 0)
-			return ret;
+	ret = ops->get_rxfh_fields(dev, &fields);
+	if (ret < 0)
+		return ret;
 
-		info.data = fields.data;
-	} else {
-		ret = ops->get_rxnfc(dev, &info, NULL);
-		if (ret < 0)
-			return ret;
-	}
+	info.data = fields.data;
 
 	return ethtool_rxnfc_copy_to_user(useraddr, &info, info_size, NULL);
 }
@@ -1528,7 +1505,7 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
 	u8 *rss_config;
 	int ret;
 
-	if ((!ops->get_rxnfc && !ops->get_rxfh_fields) || !ops->set_rxfh)
+	if (!ops->get_rxnfc || !ops->get_rxfh_fields || !ops->set_rxfh)
 		return -EOPNOTSUPP;
 
 	if (ops->get_rxfh_indir_size)