Remove the check for required and optional functions in a struct
tcp_congestion_ops from bpf_tcp_ca.c. Rely on
tcp_register_congestion_control() to reject a BPF CC that does not
implement all required functions, as it will do for a non-BPF CC.
When a CC implements tcp_congestion_ops.cong_control(), the alternate
cong_avoid() is not in use in the TCP stack. Previously, a BPF CC was
still forced to implement cong_avoid() as a no-op since it was
non-optional in bpf_tcp_ca.c.
Signed-off-by: Jörn-Thorben Hinz <jthinz@xxxxxxxxxxxxxxxxxxxx>
---
kernel/bpf/bpf_struct_ops.c | 7 +++----
net/ipv4/bpf_tcp_ca.c | 33 ---------------------------------
2 files changed, 3 insertions(+), 37 deletions(-)
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index d9a3c9207240..7e0068c3399c 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -503,10 +503,9 @@ static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
goto unlock;
}
- /* Error during st_ops->reg(). It is very unlikely since
- * the above init_member() should have caught it earlier
- * before reg(). The only possibility is if there was a race
- * in registering the struct_ops (under the same name) to
+ /* Error during st_ops->reg(). Can happen if this struct_ops needs to be
+ * verified as a whole, after all init_member() calls. Can also happen if
+ * there was a race in registering the struct_ops (under the same name) to
* a sub-system through different struct_ops's maps.
*/
set_memory_nx((long)st_map->image, 1);
diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c
index 1f5c53ede4e5..7a181631b995 100644
--- a/net/ipv4/bpf_tcp_ca.c
+++ b/net/ipv4/bpf_tcp_ca.c
@@ -14,18 +14,6 @@
/* "extern" is to avoid sparse warning. It is only used in bpf_struct_ops.c. */
extern struct bpf_struct_ops bpf_tcp_congestion_ops;
-static u32 optional_ops[] = {
- offsetof(struct tcp_congestion_ops, init),
- offsetof(struct tcp_congestion_ops, release),
- offsetof(struct tcp_congestion_ops, set_state),
- offsetof(struct tcp_congestion_ops, cwnd_event),
- offsetof(struct tcp_congestion_ops, in_ack_event),
- offsetof(struct tcp_congestion_ops, pkts_acked),
- offsetof(struct tcp_congestion_ops, min_tso_segs),
- offsetof(struct tcp_congestion_ops, sndbuf_expand),
- offsetof(struct tcp_congestion_ops, cong_control),
-};
-
static u32 unsupported_ops[] = {
offsetof(struct tcp_congestion_ops, get_info),
};
@@ -51,18 +39,6 @@ static int bpf_tcp_ca_init(struct btf *btf)
return 0;
}
-static bool is_optional(u32 member_offset)
-{
- unsigned int i;
-
- for (i = 0; i < ARRAY_SIZE(optional_ops); i++) {
- if (member_offset == optional_ops[i])
- return true;
- }
-
- return false;
-}
-
static bool is_unsupported(u32 member_offset)
{
unsigned int i;
@@ -246,7 +222,6 @@ static int bpf_tcp_ca_init_member(const struct btf_type *t,
{
const struct tcp_congestion_ops *utcp_ca;
struct tcp_congestion_ops *tcp_ca;
- int prog_fd;
u32 moff;
utcp_ca = (const struct tcp_congestion_ops *)udata;
@@ -268,14 +243,6 @@ static int bpf_tcp_ca_init_member(const struct btf_type *t,
return 1;
}
- if (!btf_type_resolve_func_ptr(btf_vmlinux, member->type, NULL))
- return 0;
-
- /* Ensure bpf_prog is provided for compulsory func ptr */
- prog_fd = (int)(*(unsigned long *)(udata + moff));
- if (!prog_fd && !is_optional(moff) && !is_unsupported(moff))
- return -EINVAL;
-
return 0;
}
--
2.30.2
