Merge branch 'add-tx-push-buf-len-param-to-ethtool'

Shay Agroskin says:

====================
Add tx push buf len param to ethtool

This patchset adds a new sub-configuration to ethtool get/set queue
params (ethtool -g) called 'tx-push-buf-len'.

This configuration specifies the maximum number of bytes of a
transmitted packet a driver can push directly to the underlying
device ('push' mode). The motivation for pushing some of the bytes to
the device has the advantages of

- Allowing a smart device to take fast actions based on the packet's
  header
- Reducing latency for small packets that can be copied completely into
  the device

This new param is practically similar to tx-copybreak value that can be
set using ethtool's tunable but conceptually serves a different purpose.
While tx-copybreak is used to reduce the overhead of DMA mapping and
makes no sense to use if less than the whole segment gets copied,
tx-push-buf-len allows to improve performance by analyzing the packet's
data (usually headers) before performing the DMA operation.

The configuration can be queried and set using the commands:

    $ ethtool -g [interface]

    # ethtool -G [interface] tx-push-buf-len [number of bytes]

This patchset also adds support for the new configuration in ENA driver
for which this parameter ensures efficient resources management on the
device side.
====================

Link: https://lore.kernel.org/r/20230323163610.1281468-1-shayagr@amazon.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/netlink/specs/ethtool.yaml

@@ -165,6 +165,12 @@ attribute-sets:
       -
         name: rx-push
         type: u8
+      -
+        name: tx-push-buf-len
+        type: u32
+      -
+        name: tx-push-buf-len-max
+        type: u32
 
   -
     name: mm-stat
@@ -311,6 +317,8 @@ operations:
             - cqe-size
             - tx-push
             - rx-push
+            - tx-push-buf-len
+            - tx-push-buf-len-max
       dump: *ring-get-op
     -
       name: rings-set

Documentation/networking/ethtool-netlink.rst

@@ -860,22 +860,24 @@ Request contents:
 
 Kernel response contents:
 
-  ====================================  ======  ===========================
-  ``ETHTOOL_A_RINGS_HEADER``            nested  reply header
-  ``ETHTOOL_A_RINGS_RX_MAX``            u32     max size of RX ring
-  ``ETHTOOL_A_RINGS_RX_MINI_MAX``       u32     max size of RX mini ring
-  ``ETHTOOL_A_RINGS_RX_JUMBO_MAX``      u32     max size of RX jumbo ring
-  ``ETHTOOL_A_RINGS_TX_MAX``            u32     max size of TX ring
-  ``ETHTOOL_A_RINGS_RX``                u32     size of RX ring
-  ``ETHTOOL_A_RINGS_RX_MINI``           u32     size of RX mini ring
-  ``ETHTOOL_A_RINGS_RX_JUMBO``          u32     size of RX jumbo ring
-  ``ETHTOOL_A_RINGS_TX``                u32     size of TX ring
-  ``ETHTOOL_A_RINGS_RX_BUF_LEN``        u32     size of buffers on the ring
-  ``ETHTOOL_A_RINGS_TCP_DATA_SPLIT``    u8      TCP header / data split
-  ``ETHTOOL_A_RINGS_CQE_SIZE``          u32     Size of TX/RX CQE
-  ``ETHTOOL_A_RINGS_TX_PUSH``           u8      flag of TX Push mode
-  ``ETHTOOL_A_RINGS_RX_PUSH``           u8      flag of RX Push mode
-  ====================================  ======  ===========================
+  =======================================   ======  ===========================
+  ``ETHTOOL_A_RINGS_HEADER``                nested  reply header
+  ``ETHTOOL_A_RINGS_RX_MAX``                u32     max size of RX ring
+  ``ETHTOOL_A_RINGS_RX_MINI_MAX``           u32     max size of RX mini ring
+  ``ETHTOOL_A_RINGS_RX_JUMBO_MAX``          u32     max size of RX jumbo ring
+  ``ETHTOOL_A_RINGS_TX_MAX``                u32     max size of TX ring
+  ``ETHTOOL_A_RINGS_RX``                    u32     size of RX ring
+  ``ETHTOOL_A_RINGS_RX_MINI``               u32     size of RX mini ring
+  ``ETHTOOL_A_RINGS_RX_JUMBO``              u32     size of RX jumbo ring
+  ``ETHTOOL_A_RINGS_TX``                    u32     size of TX ring
+  ``ETHTOOL_A_RINGS_RX_BUF_LEN``            u32     size of buffers on the ring
+  ``ETHTOOL_A_RINGS_TCP_DATA_SPLIT``        u8      TCP header / data split
+  ``ETHTOOL_A_RINGS_CQE_SIZE``              u32     Size of TX/RX CQE
+  ``ETHTOOL_A_RINGS_TX_PUSH``               u8      flag of TX Push mode
+  ``ETHTOOL_A_RINGS_RX_PUSH``               u8      flag of RX Push mode
+  ``ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN``       u32     size of TX push buffer
+  ``ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN_MAX``   u32     max size of TX push buffer
+  =======================================   ======  ===========================
 
 ``ETHTOOL_A_RINGS_TCP_DATA_SPLIT`` indicates whether the device is usable with
 page-flipping TCP zero-copy receive (``getsockopt(TCP_ZEROCOPY_RECEIVE)``).
@@ -891,6 +893,18 @@ through MMIO writes, thus reducing the latency. However, enabling this feature
 may increase the CPU cost. Drivers may enforce additional per-packet
 eligibility checks (e.g. on packet size).
 
+``ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN`` specifies the maximum number of bytes of a
+transmitted packet a driver can push directly to the underlying device
+('push' mode). Pushing some of the payload bytes to the device has the
+advantages of reducing latency for small packets by avoiding DMA mapping (same
+as ``ETHTOOL_A_RINGS_TX_PUSH`` parameter) as well as allowing the underlying
+device to process packet headers ahead of fetching its payload.
+This can help the device to make fast actions based on the packet's headers.
+This is similar to the "tx-copybreak" parameter, which copies the packet to a
+preallocated DMA memory area instead of mapping new memory. However,
+tx-push-buff parameter copies the packet directly to the device to allow the
+device to take faster actions on the packet.
+
 RINGS_SET
 =========
 
@@ -908,6 +922,7 @@ Request contents:
   ``ETHTOOL_A_RINGS_CQE_SIZE``          u32     Size of TX/RX CQE
   ``ETHTOOL_A_RINGS_TX_PUSH``           u8      flag of TX Push mode
   ``ETHTOOL_A_RINGS_RX_PUSH``           u8      flag of RX Push mode
+  ``ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN``   u32     size of TX push buffer
   ====================================  ======  ===========================
 
 Kernel checks that requested ring sizes do not exceed limits reported by

drivers/net/ethernet/amazon/ena/ena_eth_com.h

@@ -10,6 +10,10 @@
 
 /* head update threshold in units of (queue size / ENA_COMP_HEAD_THRESH) */
 #define ENA_COMP_HEAD_THRESH 4
+/* we allow 2 DMA descriptors per LLQ entry */
+#define ENA_LLQ_ENTRY_DESC_CHUNK_SIZE	(2 * sizeof(struct ena_eth_io_tx_desc))
+#define ENA_LLQ_HEADER		(128UL - ENA_LLQ_ENTRY_DESC_CHUNK_SIZE)
+#define ENA_LLQ_LARGE_HEADER	(256UL - ENA_LLQ_ENTRY_DESC_CHUNK_SIZE)
 
 struct ena_com_tx_ctx {
 	struct ena_com_tx_meta ena_meta;

drivers/net/ethernet/amazon/ena/ena_ethtool.c

@@ -476,6 +476,21 @@ static void ena_get_ringparam(struct net_device *netdev,
 
 	ring->tx_max_pending = adapter->max_tx_ring_size;
 	ring->rx_max_pending = adapter->max_rx_ring_size;
+	if (adapter->ena_dev->tx_mem_queue_type == ENA_ADMIN_PLACEMENT_POLICY_DEV) {
+		bool large_llq_supported = adapter->large_llq_header_supported;
+
+		kernel_ring->tx_push = true;
+		kernel_ring->tx_push_buf_len = adapter->ena_dev->tx_max_header_size;
+		if (large_llq_supported)
+			kernel_ring->tx_push_buf_max_len = ENA_LLQ_LARGE_HEADER;
+		else
+			kernel_ring->tx_push_buf_max_len = ENA_LLQ_HEADER;
+	} else {
+		kernel_ring->tx_push = false;
+		kernel_ring->tx_push_buf_max_len = 0;
+		kernel_ring->tx_push_buf_len = 0;
+	}
+
 	ring->tx_pending = adapter->tx_ring[0].ring_size;
 	ring->rx_pending = adapter->rx_ring[0].ring_size;
 }
@@ -486,7 +501,8 @@ static int ena_set_ringparam(struct net_device *netdev,
 			     struct netlink_ext_ack *extack)
 {
 	struct ena_adapter *adapter = netdev_priv(netdev);
-	u32 new_tx_size, new_rx_size;
+	u32 new_tx_size, new_rx_size, new_tx_push_buf_len;
+	bool changed = false;
 
 	new_tx_size = ring->tx_pending < ENA_MIN_RING_SIZE ?
 			ENA_MIN_RING_SIZE : ring->tx_pending;
@@ -496,11 +512,51 @@ static int ena_set_ringparam(struct net_device *netdev,
 			ENA_MIN_RING_SIZE : ring->rx_pending;
 	new_rx_size = rounddown_pow_of_two(new_rx_size);
 
-	if (new_tx_size == adapter->requested_tx_ring_size &&
-	    new_rx_size == adapter->requested_rx_ring_size)
+	changed |= new_tx_size != adapter->requested_tx_ring_size ||
+		   new_rx_size != adapter->requested_rx_ring_size;
+
+	/* This value is ignored if LLQ is not supported */
+	new_tx_push_buf_len = adapter->ena_dev->tx_max_header_size;
+
+	if ((adapter->ena_dev->tx_mem_queue_type == ENA_ADMIN_PLACEMENT_POLICY_DEV) !=
+	    kernel_ring->tx_push) {
+		NL_SET_ERR_MSG_MOD(extack, "Push mode state cannot be modified");
+		return -EINVAL;
+	}
+
+	/* Validate that the push buffer is supported on the underlying device */
+	if (kernel_ring->tx_push_buf_len) {
+		enum ena_admin_placement_policy_type placement;
+
+		new_tx_push_buf_len = kernel_ring->tx_push_buf_len;
+
+		placement = adapter->ena_dev->tx_mem_queue_type;
+		if (placement == ENA_ADMIN_PLACEMENT_POLICY_HOST)
+			return -EOPNOTSUPP;
+
+		if (new_tx_push_buf_len != ENA_LLQ_HEADER &&
+		    new_tx_push_buf_len != ENA_LLQ_LARGE_HEADER) {
+			bool large_llq_sup = adapter->large_llq_header_supported;
+			char large_llq_size_str[40];
+
+			snprintf(large_llq_size_str, 40, ", %lu", ENA_LLQ_LARGE_HEADER);
+
+			NL_SET_ERR_MSG_FMT_MOD(extack,
+					       "Supported tx push buff values: [%lu%s]",
+					       ENA_LLQ_HEADER,
+					       large_llq_sup ? large_llq_size_str : "");
+
+			return -EINVAL;
+		}
+
+		changed |= new_tx_push_buf_len != adapter->ena_dev->tx_max_header_size;
+	}
+
+	if (!changed)
 		return 0;
 
-	return ena_update_queue_sizes(adapter, new_tx_size, new_rx_size);
+	return ena_update_queue_params(adapter, new_tx_size, new_rx_size,
+				       new_tx_push_buf_len);
 }
 
 static u32 ena_flow_hash_to_flow_type(u16 hash_fields)
@@ -909,6 +965,8 @@ static int ena_set_tunable(struct net_device *netdev,
 static const struct ethtool_ops ena_ethtool_ops = {
 	.supported_coalesce_params = ETHTOOL_COALESCE_USECS |
 				     ETHTOOL_COALESCE_USE_ADAPTIVE_RX,
+	.supported_ring_params	= ETHTOOL_RING_USE_TX_PUSH_BUF_LEN |
+				  ETHTOOL_RING_USE_TX_PUSH,
 	.get_link_ksettings	= ena_get_link_ksettings,
 	.get_drvinfo		= ena_get_drvinfo,
 	.get_msglevel		= ena_get_msglevel,

drivers/net/ethernet/amazon/ena/ena_netdev.h

@@ -334,6 +334,14 @@ struct ena_adapter {
 
 	u32 msg_enable;
 
+	/* large_llq_header_enabled is used for two purposes:
+	 * 1. Indicates that large LLQ has been requested.
+	 * 2. Indicates whether large LLQ is set or not after device
+	 *    initialization / configuration.
+	 */
+	bool large_llq_header_enabled;
+	bool large_llq_header_supported;
+
 	u16 max_tx_sgl_size;
 	u16 max_rx_sgl_size;
 
@@ -388,9 +396,10 @@ void ena_dump_stats_to_buf(struct ena_adapter *adapter, u8 *buf);
 
 int ena_update_hw_stats(struct ena_adapter *adapter);
 
-int ena_update_queue_sizes(struct ena_adapter *adapter,
-			   u32 new_tx_size,
-			   u32 new_rx_size);
+int ena_update_queue_params(struct ena_adapter *adapter,
+			    u32 new_tx_size,
+			    u32 new_rx_size,
+			    u32 new_llq_header_len);
 
 int ena_update_queue_count(struct ena_adapter *adapter, u32 new_channel_count);
 

include/linux/ethtool.h

@@ -75,6 +75,8 @@ enum {
  * @tx_push: The flag of tx push mode
  * @rx_push: The flag of rx push mode
  * @cqe_size: Size of TX/RX completion queue event
+ * @tx_push_buf_len: Size of TX push buffer
+ * @tx_push_buf_max_len: Maximum allowed size of TX push buffer
  */
 struct kernel_ethtool_ringparam {
 	u32	rx_buf_len;
@@ -82,6 +84,8 @@ struct kernel_ethtool_ringparam {
 	u8	tx_push;
 	u8	rx_push;
 	u32	cqe_size;
+	u32	tx_push_buf_len;
+	u32	tx_push_buf_max_len;
 };
 
 /**
@@ -90,12 +94,14 @@ struct kernel_ethtool_ringparam {
  * @ETHTOOL_RING_USE_CQE_SIZE: capture for setting cqe_size
  * @ETHTOOL_RING_USE_TX_PUSH: capture for setting tx_push
  * @ETHTOOL_RING_USE_RX_PUSH: capture for setting rx_push
+ * @ETHTOOL_RING_USE_TX_PUSH_BUF_LEN: capture for setting tx_push_buf_len
  */
 enum ethtool_supported_ring_param {
-	ETHTOOL_RING_USE_RX_BUF_LEN = BIT(0),
-	ETHTOOL_RING_USE_CQE_SIZE   = BIT(1),
-	ETHTOOL_RING_USE_TX_PUSH    = BIT(2),
-	ETHTOOL_RING_USE_RX_PUSH    = BIT(3),
+	ETHTOOL_RING_USE_RX_BUF_LEN		= BIT(0),
+	ETHTOOL_RING_USE_CQE_SIZE		= BIT(1),
+	ETHTOOL_RING_USE_TX_PUSH		= BIT(2),
+	ETHTOOL_RING_USE_RX_PUSH		= BIT(3),
+	ETHTOOL_RING_USE_TX_PUSH_BUF_LEN	= BIT(4),
 };
 
 #define __ETH_RSS_HASH_BIT(bit)	((u32)1 << (bit))

include/linux/netlink.h

@@ -161,9 +161,31 @@ struct netlink_ext_ack {
 	}							\
 } while (0)
 
+#define NL_SET_ERR_MSG_ATTR_POL_FMT(extack, attr, pol, fmt, args...) do {	\
+	struct netlink_ext_ack *__extack = (extack);				\
+										\
+	if (!__extack)								\
+		break;								\
+										\
+	if (snprintf(__extack->_msg_buf, NETLINK_MAX_FMTMSG_LEN,		\
+		     "%s" fmt "%s", "", ##args, "") >=				\
+	    NETLINK_MAX_FMTMSG_LEN)						\
+		net_warn_ratelimited("%s" fmt "%s", "truncated extack: ",       \
+				     ##args, "\n");				\
+										\
+	do_trace_netlink_extack(__extack->_msg_buf);				\
+										\
+	__extack->_msg = __extack->_msg_buf;					\
+	__extack->bad_attr = (attr);						\
+	__extack->policy = (pol);						\
+} while (0)
+
 #define NL_SET_ERR_MSG_ATTR(extack, attr, msg)		\
 	NL_SET_ERR_MSG_ATTR_POL(extack, attr, NULL, msg)
 
+#define NL_SET_ERR_MSG_ATTR_FMT(extack, attr, msg, args...) \
+	NL_SET_ERR_MSG_ATTR_POL_FMT(extack, attr, NULL, msg, ##args)
+
 #define NL_SET_ERR_ATTR_MISS(extack, nest, type)  do {	\
 	struct netlink_ext_ack *__extack = (extack);	\
 							\

include/uapi/linux/ethtool_netlink.h

@@ -357,6 +357,8 @@ enum {
 	ETHTOOL_A_RINGS_CQE_SIZE,			/* u32 */
 	ETHTOOL_A_RINGS_TX_PUSH,			/* u8 */
 	ETHTOOL_A_RINGS_RX_PUSH,			/* u8 */
+	ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN,		/* u32 */
+	ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN_MAX,		/* u32 */
 
 	/* add new constants above here */
 	__ETHTOOL_A_RINGS_CNT,

net/ethtool/netlink.h

@@ -413,7 +413,7 @@ extern const struct nla_policy ethnl_features_set_policy[ETHTOOL_A_FEATURES_WANT
 extern const struct nla_policy ethnl_privflags_get_policy[ETHTOOL_A_PRIVFLAGS_HEADER + 1];
 extern const struct nla_policy ethnl_privflags_set_policy[ETHTOOL_A_PRIVFLAGS_FLAGS + 1];
 extern const struct nla_policy ethnl_rings_get_policy[ETHTOOL_A_RINGS_HEADER + 1];
-extern const struct nla_policy ethnl_rings_set_policy[ETHTOOL_A_RINGS_RX_PUSH + 1];
+extern const struct nla_policy ethnl_rings_set_policy[ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN_MAX + 1];
 extern const struct nla_policy ethnl_channels_get_policy[ETHTOOL_A_CHANNELS_HEADER + 1];
 extern const struct nla_policy ethnl_channels_set_policy[ETHTOOL_A_CHANNELS_COMBINED_COUNT + 1];
 extern const struct nla_policy ethnl_coalesce_get_policy[ETHTOOL_A_COALESCE_HEADER + 1];

net/ethtool/rings.c

@@ -11,6 +11,7 @@ struct rings_reply_data {
 	struct ethnl_reply_data		base;
 	struct ethtool_ringparam	ringparam;
 	struct kernel_ethtool_ringparam	kernel_ringparam;
+	u32				supported_ring_params;
 };
 
 #define RINGS_REPDATA(__reply_base) \
@@ -32,6 +33,8 @@ static int rings_prepare_data(const struct ethnl_req_info *req_base,
 
 	if (!dev->ethtool_ops->get_ringparam)
 		return -EOPNOTSUPP;
+
+	data->supported_ring_params = dev->ethtool_ops->supported_ring_params;
 	ret = ethnl_ops_begin(dev);
 	if (ret < 0)
 		return ret;
@@ -57,7 +60,9 @@ static int rings_reply_size(const struct ethnl_req_info *req_base,
 	       nla_total_size(sizeof(u8))  +	/* _RINGS_TCP_DATA_SPLIT */
 	       nla_total_size(sizeof(u32)  +	/* _RINGS_CQE_SIZE */
 	       nla_total_size(sizeof(u8))  +	/* _RINGS_TX_PUSH */
-	       nla_total_size(sizeof(u8)));	/* _RINGS_RX_PUSH */
+	       nla_total_size(sizeof(u8))) +	/* _RINGS_RX_PUSH */
+	       nla_total_size(sizeof(u32)) +	/* _RINGS_TX_PUSH_BUF_LEN */
+	       nla_total_size(sizeof(u32));	/* _RINGS_TX_PUSH_BUF_LEN_MAX */
 }
 
 static int rings_fill_reply(struct sk_buff *skb,
@@ -67,6 +72,7 @@ static int rings_fill_reply(struct sk_buff *skb,
 	const struct rings_reply_data *data = RINGS_REPDATA(reply_base);
 	const struct kernel_ethtool_ringparam *kr = &data->kernel_ringparam;
 	const struct ethtool_ringparam *ringparam = &data->ringparam;
+	u32 supported_ring_params = data->supported_ring_params;
 
 	WARN_ON(kr->tcp_data_split > ETHTOOL_TCP_DATA_SPLIT_ENABLED);
 
@@ -98,7 +104,12 @@ static int rings_fill_reply(struct sk_buff *skb,
 	    (kr->cqe_size &&
 	     (nla_put_u32(skb, ETHTOOL_A_RINGS_CQE_SIZE, kr->cqe_size))) ||
 	    nla_put_u8(skb, ETHTOOL_A_RINGS_TX_PUSH, !!kr->tx_push) ||
-	    nla_put_u8(skb, ETHTOOL_A_RINGS_RX_PUSH, !!kr->rx_push))
+	    nla_put_u8(skb, ETHTOOL_A_RINGS_RX_PUSH, !!kr->rx_push) ||
+	    ((supported_ring_params & ETHTOOL_RING_USE_TX_PUSH_BUF_LEN) &&
+	     (nla_put_u32(skb, ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN_MAX,
+			  kr->tx_push_buf_max_len) ||
+	      nla_put_u32(skb, ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN,
+			  kr->tx_push_buf_len))))
 		return -EMSGSIZE;
 
 	return 0;
@@ -117,6 +128,7 @@ const struct nla_policy ethnl_rings_set_policy[] = {
 	[ETHTOOL_A_RINGS_CQE_SIZE]		= NLA_POLICY_MIN(NLA_U32, 1),
 	[ETHTOOL_A_RINGS_TX_PUSH]		= NLA_POLICY_MAX(NLA_U8, 1),
 	[ETHTOOL_A_RINGS_RX_PUSH]		= NLA_POLICY_MAX(NLA_U8, 1),
+	[ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN]	= { .type = NLA_U32 },
 };
 
 static int
@@ -158,6 +170,14 @@ ethnl_set_rings_validate(struct ethnl_req_info *req_info,
 		return -EOPNOTSUPP;
 	}
 
+	if (tb[ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN] &&
+	    !(ops->supported_ring_params & ETHTOOL_RING_USE_TX_PUSH_BUF_LEN)) {
+		NL_SET_ERR_MSG_ATTR(info->extack,
+				    tb[ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN],
+				    "setting tx push buf len is not supported");
+		return -EOPNOTSUPP;
+	}
+
 	return ops->get_ringparam && ops->set_ringparam ? 1 : -EOPNOTSUPP;
 }
 
@@ -189,6 +209,8 @@ ethnl_set_rings(struct ethnl_req_info *req_info, struct genl_info *info)
 			tb[ETHTOOL_A_RINGS_TX_PUSH], &mod);
 	ethnl_update_u8(&kernel_ringparam.rx_push,
 			tb[ETHTOOL_A_RINGS_RX_PUSH], &mod);
+	ethnl_update_u32(&kernel_ringparam.tx_push_buf_len,
+			 tb[ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN], &mod);
 	if (!mod)
 		return 0;
 
@@ -209,6 +231,14 @@ ethnl_set_rings(struct ethnl_req_info *req_info, struct genl_info *info)
 		return -EINVAL;
 	}
 
+	if (kernel_ringparam.tx_push_buf_len > kernel_ringparam.tx_push_buf_max_len) {
+		NL_SET_ERR_MSG_ATTR_FMT(info->extack, tb[ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN],
+					"Requested TX push buffer exceeds the maximum of %u",
+					kernel_ringparam.tx_push_buf_max_len);
+
+		return -EINVAL;
+	}
+
 	ret = dev->ethtool_ops->set_ringparam(dev, &ringparam,
 					      &kernel_ringparam, info->extack);
 	return ret < 0 ? ret : 1;