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authorJakub Kicinski <kuba@kernel.org>2022-01-27 10:42:59 -0800
committerDavid S. Miller <davem@davemloft.net>2022-01-28 14:43:47 +0000
commit9690ae60429020f38e4aa2540c306f27eb021bc0 (patch)
tree05901b52f36783cdd5b53e2327752792304dc575
parent1a918a32cd1fbb3789e80d0d801533d1b9516b24 (diff)
downloadlinux-9690ae60429020f38e4aa2540c306f27eb021bc0.tar.bz2
ethtool: add header/data split indication
For applications running on a mix of platforms it's useful to have a clear indication whether host's NIC supports the geometry requirements of TCP zero-copy. TCP zero-copy Rx requires data to be neatly placed into memory pages. Most NICs can't do that. This patch is adding GET support only, since the NICs I work with either always have the feature enabled or enable it whenever MTU is set to jumbo. In other words I don't need SET. But adding set should be trivial. (The only note on SET is that we will likely want the setting to be "sticky" and use 0 / `unknown` to reset it back to driver default.) Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--Documentation/networking/ethtool-netlink.rst8
-rw-r--r--include/linux/ethtool.h2
-rw-r--r--include/uapi/linux/ethtool_netlink.h7
-rw-r--r--net/ethtool/rings.c15
4 files changed, 27 insertions, 5 deletions
diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index 9d98e0511249..cae28af7a476 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -860,8 +860,16 @@ Kernel response contents:
``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_TCP_DATA_SPLIT`` indicates whether the device is usable with
+page-flipping TCP zero-copy receive (``getsockopt(TCP_ZEROCOPY_RECEIVE)``).
+If enabled the device is configured to place frame headers and data into
+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.
+
RINGS_SET
=========
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 11efc45de66a..e0853f48b75e 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -70,9 +70,11 @@ 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
*/
struct kernel_ethtool_ringparam {
u32 rx_buf_len;
+ u8 tcp_data_split;
};
/**
diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index cca6e474a085..417d4280d7b5 100644
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -319,6 +319,12 @@ enum {
/* RINGS */
enum {
+ ETHTOOL_TCP_DATA_SPLIT_UNKNOWN = 0,
+ ETHTOOL_TCP_DATA_SPLIT_DISABLED,
+ ETHTOOL_TCP_DATA_SPLIT_ENABLED,
+};
+
+enum {
ETHTOOL_A_RINGS_UNSPEC,
ETHTOOL_A_RINGS_HEADER, /* nest - _A_HEADER_* */
ETHTOOL_A_RINGS_RX_MAX, /* u32 */
@@ -330,6 +336,7 @@ enum {
ETHTOOL_A_RINGS_RX_JUMBO, /* u32 */
ETHTOOL_A_RINGS_TX, /* u32 */
ETHTOOL_A_RINGS_RX_BUF_LEN, /* u32 */
+ ETHTOOL_A_RINGS_TCP_DATA_SPLIT, /* u8 */
/* add new constants above here */
__ETHTOOL_A_RINGS_CNT,
diff --git a/net/ethtool/rings.c b/net/ethtool/rings.c
index c1d5f5e0fdc9..18a5035d3bee 100644
--- a/net/ethtool/rings.c
+++ b/net/ethtool/rings.c
@@ -53,7 +53,8 @@ static int rings_reply_size(const struct ethnl_req_info *req_base,
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_RX_BUF_LEN */
+ nla_total_size(sizeof(u32)) + /* _RINGS_RX_BUF_LEN */
+ nla_total_size(sizeof(u8)); /* _RINGS_TCP_DATA_SPLIT */
}
static int rings_fill_reply(struct sk_buff *skb,
@@ -61,9 +62,11 @@ 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 kernel_ethtool_ringparam *kr = &data->kernel_ringparam;
const struct ethtool_ringparam *ringparam = &data->ringparam;
+ WARN_ON(kr->tcp_data_split > ETHTOOL_TCP_DATA_SPLIT_ENABLED);
+
if ((ringparam->rx_max_pending &&
(nla_put_u32(skb, ETHTOOL_A_RINGS_RX_MAX,
ringparam->rx_max_pending) ||
@@ -84,9 +87,11 @@ static int rings_fill_reply(struct sk_buff *skb,
ringparam->tx_max_pending) ||
nla_put_u32(skb, ETHTOOL_A_RINGS_TX,
ringparam->tx_pending))) ||
- (kernel_ringparam->rx_buf_len &&
- (nla_put_u32(skb, ETHTOOL_A_RINGS_RX_BUF_LEN,
- kernel_ringparam->rx_buf_len))))
+ (kr->rx_buf_len &&
+ (nla_put_u32(skb, ETHTOOL_A_RINGS_RX_BUF_LEN, kr->rx_buf_len))) ||
+ (kr->tcp_data_split &&
+ (nla_put_u8(skb, ETHTOOL_A_RINGS_TCP_DATA_SPLIT,
+ kr->tcp_data_split))))
return -EMSGSIZE;
return 0;