[PATCH RFC net-next v2 4/6] net: devmem: TCP tx netlink api

Mina Almasry
2025-01-30T21:15:49Z

From: Stanislav Fomichev <sdf@fomichev.me>

Add bind-tx netlink call to attach dmabuf for TX; queue is not
required, only ifindex and dmabuf fd for attachment.

Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Mina Almasry <almasrymina@google.com>

---
Documentation/netlink/specs/netdev.yaml | 12 ++++++++++++
include/uapi/linux/netdev.h | 1 +
net/core/netdev-genl-gen.c | 13 +++++++++++++
net/core/netdev-genl-gen.h | 1 +
net/core/netdev-genl.c | 6 ++++++
tools/include/uapi/linux/netdev.h | 1 +
6 files changed, 34 insertions(+)

diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
index cbb544bd6c84..93f4333e7bc6 100644
--- a/Documentation/netlink/specs/netdev.yaml
+++ b/Documentation/netlink/specs/netdev.yaml
@@ -711,6 +711,18 @@ operations:
- defer-hard-irqs
- gro-flush-timeout
- irq-suspend-timeout
+ -
+ name: bind-tx
+ doc: Bind dmabuf to netdev for TX
+ attribute-set: dmabuf
+ do:
+ request:
+ attributes:
+ - ifindex
+ - fd
+ reply:
+ attributes:
+ - id

kernel-family:
headers: [ "linux/list.h"]
diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h
index e4be227d3ad6..04364ef5edbe 100644
--- a/include/uapi/linux/netdev.h
+++ b/include/uapi/linux/netdev.h
@@ -203,6 +203,7 @@ enum {
NETDEV_CMD_QSTATS_GET,
NETDEV_CMD_BIND_RX,
NETDEV_CMD_NAPI_SET,
+ NETDEV_CMD_BIND_TX,

__NETDEV_CMD_MAX,
NETDEV_CMD_MAX = (__NETDEV_CMD_MAX - 1)
diff --git a/net/core/netdev-genl-gen.c b/net/core/netdev-genl-gen.c
index 996ac6a449eb..9e947284e42d 100644
--- a/net/core/netdev-genl-gen.c
+++ b/net/core/netdev-genl-gen.c
@@ -99,6 +99,12 @@ static const struct nla_policy netdev_napi_set_nl_policy[NETDEV_A_NAPI_IRQ_SUSPE
[NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT] = { .type = NLA_UINT, },
};

+/* NETDEV_CMD_BIND_TX - do */
+static const struct nla_policy netdev_bind_tx_nl_policy[NETDEV_A_DMABUF_FD + 1] = {
+ [NETDEV_A_DMABUF_IFINDEX] = NLA_POLICY_MIN(NLA_U32, 1),
+ [NETDEV_A_DMABUF_FD] = { .type = NLA_U32, },
+};
+
/* Ops table for netdev */
static const struct genl_split_ops netdev_nl_ops[] = {
{
@@ -190,6 +196,13 @@ static const struct genl_split_ops netdev_nl_ops[] = {
.maxattr = NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT,
.flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
},
+ {
+ .cmd = NETDEV_CMD_BIND_TX,
+ .doit = netdev_nl_bind_tx_doit,
+ .policy = netdev_bind_tx_nl_policy,
+ .maxattr = NETDEV_A_DMABUF_FD,
+ .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+ },
};

static const struct genl_multicast_group netdev_nl_mcgrps[] = {
diff --git a/net/core/netdev-genl-gen.h b/net/core/netdev-genl-gen.h
index e09dd7539ff2..c1fed66e92b9 100644
--- a/net/core/netdev-genl-gen.h
+++ b/net/core/netdev-genl-gen.h
@@ -34,6 +34,7 @@ int netdev_nl_qstats_get_dumpit(struct sk_buff *skb,
struct netlink_callback *cb);
int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info);
int netdev_nl_napi_set_doit(struct sk_buff *skb, struct genl_info *info);
+int netdev_nl_bind_tx_doit(struct sk_buff *skb, struct genl_info *info);

enum {
NETDEV_NLGRP_MGMT,
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 715f85c6b62e..0e41699df419 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -911,6 +911,12 @@ int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
return err;
}

+/* stub */
+int netdev_nl_bind_tx_doit(struct sk_buff *skb, struct genl_info *info)
+{
+ return 0;
+}
+
void netdev_nl_sock_priv_init(struct list_head *priv)
{
INIT_LIST_HEAD(priv);
diff --git a/tools/include/uapi/linux/netdev.h b/tools/include/uapi/linux/netdev.h
index e4be227d3ad6..04364ef5edbe 100644
--- a/tools/include/uapi/linux/netdev.h
+++ b/tools/include/uapi/linux/netdev.h
@@ -203,6 +203,7 @@ enum {
NETDEV_CMD_QSTATS_GET,
NETDEV_CMD_BIND_RX,
NETDEV_CMD_NAPI_SET,
+ NETDEV_CMD_BIND_TX,

__NETDEV_CMD_MAX,
NETDEV_CMD_MAX = (__NETDEV_CMD_MAX - 1)
--
2.48.1.362.g079036d154-goog