ethtool: add SET for TCP_DATA_SPLIT ringparam

Follow up commit 9690ae604290 ("ethtool: add header/data split
indication") and add the set part of Ethtool's header split, i.e.
ability to enable/disable header split via the Ethtool Netlink
interface. This might be helpful to optimize the setup for particular
workloads, for example, to avoid XDP frags, and so on.
A driver should advertise ``ETHTOOL_RING_USE_TCP_DATA_SPLIT`` in its
ops->supported_ring_params to allow doing that. "Unknown" passed from
the userspace when the header split is supported means the driver is
free to choose the preferred state.

Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://lore.kernel.org/r/20231212142752.935000-2-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index deb683d3360f076368a65714feea749a501d294e..67b30940234bec0c6e09ad9544c8a6183905c2f6 100644 (file)
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -95,6 +95,7 @@ struct kernel_ethtool_ringparam {
  * @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
+ * @ETHTOOL_RING_USE_TCP_DATA_SPLIT: capture for setting tcp_data_split
  */
 enum ethtool_supported_ring_param {
        ETHTOOL_RING_USE_RX_BUF_LEN             = BIT(0),
@@ -102,6 +103,7 @@ enum ethtool_supported_ring_param {
        ETHTOOL_RING_USE_TX_PUSH                = BIT(2),
        ETHTOOL_RING_USE_RX_PUSH                = BIT(3),
        ETHTOOL_RING_USE_TX_PUSH_BUF_LEN        = BIT(4),
+       ETHTOOL_RING_USE_TCP_DATA_SPLIT         = BIT(5),
 };
 
 #define __ETH_RSS_HASH_BIT(bit)        ((u32)1 << (bit))

diff --git a/net/ethtool/rings.c b/net/ethtool/rings.c
index fb09f774ea01deb43ab02403fac15ca15f9b74c6..b7865a14fdf8fab5c54a6d66cd167bbfd60d65bc 100644 (file)
--- a/net/ethtool/rings.c
+++ b/net/ethtool/rings.c
@@ -124,6 +124,8 @@ const struct nla_policy ethnl_rings_set_policy[] = {
        [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),
+       [ETHTOOL_A_RINGS_TCP_DATA_SPLIT]        =
+               NLA_POLICY_MAX(NLA_U8, ETHTOOL_TCP_DATA_SPLIT_ENABLED),
        [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),
@@ -145,6 +147,14 @@ ethnl_set_rings_validate(struct ethnl_req_info *req_info,
                return -EOPNOTSUPP;
        }
 
+       if (tb[ETHTOOL_A_RINGS_TCP_DATA_SPLIT] &&
+           !(ops->supported_ring_params & ETHTOOL_RING_USE_TCP_DATA_SPLIT)) {
+               NL_SET_ERR_MSG_ATTR(info->extack,
+                                   tb[ETHTOOL_A_RINGS_TCP_DATA_SPLIT],
+                                   "setting TCP data split is not supported");
+               return -EOPNOTSUPP;
+       }
+
        if (tb[ETHTOOL_A_RINGS_CQE_SIZE] &&
            !(ops->supported_ring_params & ETHTOOL_RING_USE_CQE_SIZE)) {
                NL_SET_ERR_MSG_ATTR(info->extack,
@@ -202,6 +212,8 @@ ethnl_set_rings(struct ethnl_req_info *req_info, struct genl_info *info)
        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);
+       ethnl_update_u8(&kernel_ringparam.tcp_data_split,
+                       tb[ETHTOOL_A_RINGS_TCP_DATA_SPLIT], &mod);
        ethnl_update_u32(&kernel_ringparam.cqe_size,
                         tb[ETHTOOL_A_RINGS_CQE_SIZE], &mod);
        ethnl_update_u8(&kernel_ringparam.tx_push,