net: ethtool: extend ringparam set/get APIs for rx_push

Similar to what was done for TX_PUSH, add an RX_PUSH concept
to the ethtool interfaces.

Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: emusln

Documentation/networking/ethtool-netlink.rst

@@ -874,6 +874,7 @@ Kernel response contents:
   ``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_TCP_DATA_SPLIT`` indicates whether the device is usable with
@@ -883,8 +884,8 @@ separate buffers. The device configuration must make it possible to receive
 full memory pages of data, for example because MTU is high enough or through
 HW-GRO.
 
-``ETHTOOL_A_RINGS_TX_PUSH`` flag is used to enable descriptor fast
-path to send packets. In ordinary path, driver fills descriptors in DRAM and
+``ETHTOOL_A_RINGS_[RX|TX]_PUSH`` flag is used to enable descriptor fast
+path to send or receive packets. In ordinary path, driver fills descriptors in DRAM and
 notifies NIC hardware. In fast path, driver pushes descriptors to the device
 through MMIO writes, thus reducing the latency. However, enabling this feature
 may increase the CPU cost. Drivers may enforce additional per-packet
@@ -906,6 +907,7 @@ Request contents:
   ``ETHTOOL_A_RINGS_RX_BUF_LEN``        u32     size of buffers on the ring
   ``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
   ====================================  ======  ===========================
 
 Kernel checks that requested ring sizes do not exceed limits reported by

include/linux/ethtool.h

@@ -73,12 +73,14 @@ enum {
  * @rx_buf_len: Current length of buffers on the rx ring.
  * @tcp_data_split: Scatter packet headers and data to separate buffers
  * @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
  */
 struct kernel_ethtool_ringparam {
 	u32	rx_buf_len;
 	u8	tcp_data_split;
 	u8	tx_push;
+	u8	rx_push;
 	u32	cqe_size;
 };
 
@@ -87,11 +89,13 @@ struct kernel_ethtool_ringparam {
  * @ETHTOOL_RING_USE_RX_BUF_LEN: capture for setting rx_buf_len
  * @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
  */
 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),
 };
 
 #define __ETH_RSS_HASH_BIT(bit)	((u32)1 << (bit))

include/uapi/linux/ethtool_netlink.h

@@ -356,6 +356,7 @@ enum {
 	ETHTOOL_A_RINGS_TCP_DATA_SPLIT,			/* u8 */
 	ETHTOOL_A_RINGS_CQE_SIZE,			/* u32 */
 	ETHTOOL_A_RINGS_TX_PUSH,			/* u8 */
+	ETHTOOL_A_RINGS_RX_PUSH,			/* u8 */
 
 	/* 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_TX_PUSH + 1];
+extern const struct nla_policy ethnl_rings_set_policy[ETHTOOL_A_RINGS_RX_PUSH + 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

@@ -56,7 +56,8 @@ static int rings_reply_size(const struct ethnl_req_info *req_base,
 	       nla_total_size(sizeof(u32)) +	/* _RINGS_RX_BUF_LEN */
 	       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_TX_PUSH */
+	       nla_total_size(sizeof(u8)));	/* _RINGS_RX_PUSH */
 }
 
 static int rings_fill_reply(struct sk_buff *skb,
@@ -96,7 +97,8 @@ static int rings_fill_reply(struct sk_buff *skb,
 			 kr->tcp_data_split))) ||
 	    (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_TX_PUSH, !!kr->tx_push) ||
+	    nla_put_u8(skb, ETHTOOL_A_RINGS_RX_PUSH, !!kr->rx_push))
 		return -EMSGSIZE;
 
 	return 0;
@@ -114,6 +116,7 @@ const struct nla_policy ethnl_rings_set_policy[] = {
 	[ETHTOOL_A_RINGS_RX_BUF_LEN]            = NLA_POLICY_MIN(NLA_U32, 1),
 	[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),
 };
 
 static int
@@ -147,6 +150,14 @@ ethnl_set_rings_validate(struct ethnl_req_info *req_info,
 		return -EOPNOTSUPP;
 	}
 
+	if (tb[ETHTOOL_A_RINGS_RX_PUSH] &&
+	    !(ops->supported_ring_params & ETHTOOL_RING_USE_RX_PUSH)) {
+		NL_SET_ERR_MSG_ATTR(info->extack,
+				    tb[ETHTOOL_A_RINGS_RX_PUSH],
+				    "setting rx push not supported");
+		return -EOPNOTSUPP;
+	}
+
 	return ops->get_ringparam && ops->set_ringparam ? 1 : -EOPNOTSUPP;
 }
 
@@ -176,6 +187,8 @@ ethnl_set_rings(struct ethnl_req_info *req_info, struct genl_info *info)
 			 tb[ETHTOOL_A_RINGS_CQE_SIZE], &mod);
 	ethnl_update_u8(&kernel_ringparam.tx_push,
 			tb[ETHTOOL_A_RINGS_TX_PUSH], &mod);
+	ethnl_update_u8(&kernel_ringparam.rx_push,
+			tb[ETHTOOL_A_RINGS_RX_PUSH], &mod);
 	if (!mod)
 		return 0;