Merge branch 'net-ethtool-add-dedicated-grxrings-driver-callbacks'

Breno Leitao says:

====================
net: ethtool: add dedicated GRXRINGS driver callbacks

This patchset introduces a new dedicated ethtool_ops callback,
.get_rx_ring_count, which enables drivers to provide the number of RX
rings directly, improving efficiency and clarity in RX ring queries and
RSS configuration.

Number of drivers implements .get_rxnfc callback just to report the ring
count, so, having a proper callback makes sense and simplify .get_rxnfc
(in some cases remove it completely).

This has been suggested by Jakub, and follow the same idea as RXFH
driver callbacks [1].

This also port virtio_net to this new callback. Once there is consensus
on this approach, I can start moving the drivers to this new callback.

Link: https://lore.kernel.org/all/20250611145949.2674086-1-kuba@kernel.org/ [1]

v3: https://lore.kernel.org/20250915-gxrings-v3-0-bfd717dbcaad@debian.org
v2: https://lore.kernel.org/20250912-gxrings-v2-0-3c7a60bbeebf@debian.org
v1: https://lore.kernel.org/20250909-gxrings-v1-0-634282f06a54@debian.org
RFC: https://lore.kernel.org/20250905-gxrings-v1-0-984fc471f28f@debian.org
====================

Link: https://patch.msgid.link/20250917-gxrings-v4-0-dae520e2e1cb@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 20 insertions, 0 deletions

diff --git a/net/ethtool/common.c b/net/ethtool/common.c
index 4f58648a27ad..10460ea3717c 100644
--- a/net/ethtool/common.c
+++ b/net/ethtool/common.c
@@ -577,6 +577,26 @@ int __ethtool_get_link(struct net_device *dev)
 	return netif_running(dev) && dev->ethtool_ops->get_link(dev);
 }
 
+int ethtool_get_rx_ring_count(struct net_device *dev)
+{
+	const struct ethtool_ops *ops = dev->ethtool_ops;
+	struct ethtool_rxnfc rx_rings = {};
+	int ret;
+
+	if (ops->get_rx_ring_count)
+		return ops->get_rx_ring_count(dev);
+
+	if (!ops->get_rxnfc)
+		return -EOPNOTSUPP;
+
+	rx_rings.cmd = ETHTOOL_GRXRINGS;
+	ret = ops->get_rxnfc(dev, &rx_rings, NULL);
+	if (ret < 0)
+		return ret;
+
+	return rx_rings.data;
+}
+
 static int ethtool_get_rxnfc_rule_count(struct net_device *dev)
 {
 	const struct ethtool_ops *ops = dev->ethtool_ops;