[PATCH net-next v5 2/7] net: ethtool: add tcp_data_split_mod member in kernel_ethtool_ringparam

[Taehee Yoo <ap420073@gmail.com>]

When tcp-data-split is UNKNOWN mode, drivers arbitrarily handle it.
For example, bnxt_en driver automatically enables if at least one of
LRO/GRO/JUMBO is enabled.
If tcp-data-split is UNKNOWN and LRO is enabled, a driver returns
ENABLES of tcp-data-split, not UNKNOWN.
So, `ethtool -g eth0` shows tcp-data-split is enabled.

The problem is in the setting situation.
In the ethnl_set_rings(), it first calls get_ringparam() to get the
current driver's config.
At that moment, if driver's tcp-data-split config is UNKNOWN, it returns
ENABLE if LRO/GRO/JUMBO is enabled.
Then, it sets values from the user and driver's current config to
kernel_ethtool_ringparam.
Last it calls .set_ringparam().
The driver, especially bnxt_en driver receives
ETHTOOL_TCP_DATA_SPLIT_ENABLED.
But it can't distinguish whether it is set by the user or just the
current config.

The new tcp_data_split_mod member indicates the tcp-data-split value is
explicitly set by the user.
So the driver can handle ETHTOOL_TCP_DATA_SPLIT_ENABLED properly.

Signed-off-by: Taehee Yoo <ap420073@gmail.com>
---

v5:
 - Patch added.

 include/linux/ethtool.h | 2 ++
 net/ethtool/rings.c     | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 1199e308c8dd..ecd52b99a63a 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -73,6 +73,7 @@ enum {
  * struct kernel_ethtool_ringparam - RX/TX ring configuration
  * @rx_buf_len: Current length of buffers on the rx ring.
  * @tcp_data_split: Scatter packet headers and data to separate buffers
+ * @tcp_data_split_mod: Updated tcp-data-split from user
  * @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
@@ -82,6 +83,7 @@ enum {
 struct kernel_ethtool_ringparam {
 	u32	rx_buf_len;
 	u8	tcp_data_split;
+	bool	tcp_data_split_mod;
 	u8	tx_push;
 	u8	rx_push;
 	u32	cqe_size;
diff --git a/net/ethtool/rings.c b/net/ethtool/rings.c
index b7865a14fdf8..c12ebb61394d 100644
--- a/net/ethtool/rings.c
+++ b/net/ethtool/rings.c
@@ -250,6 +250,9 @@ ethnl_set_rings(struct ethnl_req_info *req_info, struct genl_info *info)
 		return -EINVAL;
 	}
 
+	if (tb[ETHTOOL_A_RINGS_TCP_DATA_SPLIT])
+		kernel_ringparam.tcp_data_split_mod = true;
+
 	ret = dev->ethtool_ops->set_ringparam(dev, &ringparam,
 					      &kernel_ringparam, info->extack);
 	return ret < 0 ? ret : 1;
-- 
2.34.1