ethtool: add support to set/get rx buf len via ethtool

Add support to set rx buf len via ethtool -G parameter and get
rx buf len via ethtool -g parameter.
Signed-off-by: Hao Chen <chenhao288@hisilicon.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/ethtool-netlink.rst

@@ -849,7 +849,7 @@ 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
@@ -859,7 +859,8 @@ Kernel response contents:
   ``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
+  ====================================  ======  ===========================
 
 
 RINGS_SET
@@ -869,13 +870,14 @@ Sets ring sizes like ``ETHTOOL_SRINGPARAM`` ioctl request.
 
 Request contents:
 
-  ====================================  ======  ==========================
+  ====================================  ======  ===========================
   ``ETHTOOL_A_RINGS_HEADER``            nested  reply header
   ``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
+  ====================================  ======  ===========================
 
 Kernel checks that requested ring sizes do not exceed limits reported by
 driver. Driver may impose additional constraints and may not suspport all

include/linux/ethtool.h

@@ -67,6 +67,22 @@ enum {
 	ETH_RSS_HASH_FUNCS_COUNT
 };
 
+/**
+ * struct kernel_ethtool_ringparam - RX/TX ring configuration
+ * @rx_buf_len: Current length of buffers on the rx ring.
+ */
+struct kernel_ethtool_ringparam {
+	u32	rx_buf_len;
+};
+
+/**
+ * enum ethtool_supported_ring_param - indicator caps for setting ring params
+ * @ETHTOOL_RING_USE_RX_BUF_LEN: capture for setting rx_buf_len
+ */
+enum ethtool_supported_ring_param {
+	ETHTOOL_RING_USE_RX_BUF_LEN = BIT(0),
+};
+
 #define __ETH_RSS_HASH_BIT(bit)	((u32)1 << (bit))
 #define __ETH_RSS_HASH(name)	__ETH_RSS_HASH_BIT(ETH_RSS_HASH_##name##_BIT)
 
@@ -432,6 +448,7 @@ struct ethtool_module_power_mode_params {
  * @cap_link_lanes_supported: indicates if the driver supports lanes
  *	parameter.
  * @supported_coalesce_params: supported types of interrupt coalescing.
+ * @supported_ring_params: supported ring params.
  * @get_drvinfo: Report driver/device information.  Should only set the
  *	@driver, @version, @fw_version and @bus_info fields.  If not
  *	implemented, the @driver and @bus_info fields will be filled in
@@ -613,6 +630,7 @@ struct ethtool_module_power_mode_params {
 struct ethtool_ops {
 	u32     cap_link_lanes_supported:1;
 	u32	supported_coalesce_params;
+	u32	supported_ring_params;
 	void	(*get_drvinfo)(struct net_device *, struct ethtool_drvinfo *);
 	int	(*get_regs_len)(struct net_device *);
 	void	(*get_regs)(struct net_device *, struct ethtool_regs *, void *);

include/uapi/linux/ethtool_netlink.h

@@ -329,6 +329,7 @@ enum {
 	ETHTOOL_A_RINGS_RX_MINI,			/* u32 */
 	ETHTOOL_A_RINGS_RX_JUMBO,			/* u32 */
 	ETHTOOL_A_RINGS_TX,				/* u32 */
+	ETHTOOL_A_RINGS_RX_BUF_LEN,                     /* u32 */
 
 	/* add new constants above here */
 	__ETHTOOL_A_RINGS_CNT,

net/ethtool/netlink.h

@@ -356,7 +356,7 @@ 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 + 1];
+extern const struct nla_policy ethnl_rings_set_policy[ETHTOOL_A_RINGS_RX_BUF_LEN + 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

@@ -10,6 +10,7 @@ struct rings_req_info {
 struct rings_reply_data {
 	struct ethnl_reply_data		base;
 	struct ethtool_ringparam	ringparam;
+	struct kernel_ethtool_ringparam	kernel_ringparam;
 };
 
 #define RINGS_REPDATA(__reply_base) \
@@ -49,7 +50,8 @@ static int rings_reply_size(const struct ethnl_req_info *req_base,
 	       nla_total_size(sizeof(u32)) +	/* _RINGS_RX */
 	       nla_total_size(sizeof(u32)) +	/* _RINGS_RX_MINI */
 	       nla_total_size(sizeof(u32)) +	/* _RINGS_RX_JUMBO */
-	       nla_total_size(sizeof(u32));	/* _RINGS_TX */
+	       nla_total_size(sizeof(u32)) +	/* _RINGS_TX */
+	       nla_total_size(sizeof(u32));     /* _RINGS_RX_BUF_LEN */
 }
 
 static int rings_fill_reply(struct sk_buff *skb,
@@ -57,6 +59,7 @@ static int rings_fill_reply(struct sk_buff *skb,
 			    const struct ethnl_reply_data *reply_base)
 {
 	const struct rings_reply_data *data = RINGS_REPDATA(reply_base);
+	const struct kernel_ethtool_ringparam *kernel_ringparam = &data->kernel_ringparam;
 	const struct ethtool_ringparam *ringparam = &data->ringparam;
 
 	if ((ringparam->rx_max_pending &&
@@ -78,7 +81,10 @@ static int rings_fill_reply(struct sk_buff *skb,
 	     (nla_put_u32(skb, ETHTOOL_A_RINGS_TX_MAX,
 			  ringparam->tx_max_pending) ||
 	      nla_put_u32(skb, ETHTOOL_A_RINGS_TX,
-			  ringparam->tx_pending))))
+			  ringparam->tx_pending)))  ||
+	    (kernel_ringparam->rx_buf_len &&
+	     (nla_put_u32(skb, ETHTOOL_A_RINGS_RX_BUF_LEN,
+			  kernel_ringparam->rx_buf_len))))
 		return -EMSGSIZE;
 
 	return 0;
@@ -105,10 +111,12 @@ const struct nla_policy ethnl_rings_set_policy[] = {
 	[ETHTOOL_A_RINGS_RX_MINI]		= { .type = NLA_U32 },
 	[ETHTOOL_A_RINGS_RX_JUMBO]		= { .type = NLA_U32 },
 	[ETHTOOL_A_RINGS_TX]			= { .type = NLA_U32 },
+	[ETHTOOL_A_RINGS_RX_BUF_LEN]            = NLA_POLICY_MIN(NLA_U32, 1),
 };
 
 int ethnl_set_rings(struct sk_buff *skb, struct genl_info *info)
 {
+	struct kernel_ethtool_ringparam kernel_ringparam = {};
 	struct ethtool_ringparam ringparam = {};
 	struct ethnl_req_info req_info = {};
 	struct nlattr **tb = info->attrs;
@@ -142,6 +150,8 @@ int ethnl_set_rings(struct sk_buff *skb, struct genl_info *info)
 	ethnl_update_u32(&ringparam.rx_jumbo_pending,
 			 tb[ETHTOOL_A_RINGS_RX_JUMBO], &mod);
 	ethnl_update_u32(&ringparam.tx_pending, tb[ETHTOOL_A_RINGS_TX], &mod);
+	ethnl_update_u32(&kernel_ringparam.rx_buf_len,
+			 tb[ETHTOOL_A_RINGS_RX_BUF_LEN], &mod);
 	ret = 0;
 	if (!mod)
 		goto out_ops;
@@ -164,6 +174,15 @@ int ethnl_set_rings(struct sk_buff *skb, struct genl_info *info)
 		goto out_ops;
 	}
 
+	if (kernel_ringparam.rx_buf_len != 0 &&
+	    !(ops->supported_ring_params & ETHTOOL_RING_USE_RX_BUF_LEN)) {
+		ret = -EOPNOTSUPP;
+		NL_SET_ERR_MSG_ATTR(info->extack,
+				    tb[ETHTOOL_A_RINGS_RX_BUF_LEN],
+				    "setting rx buf len not supported");
+		goto out_ops;
+	}
+
 	ret = dev->ethtool_ops->set_ringparam(dev, &ringparam);
 	if (ret < 0)
 		goto out_ops;