Re: [PATCH mptcp-next v18 5/7] mptcp: add bpf_mptcp_sched_ops

[Paolo Abeni <pabeni@redhat.com>]

Hello,

On Sun, 2022-05-01 at 21:48 +0800, Geliang Tang wrote:
> This patch implements a new struct bpf_struct_ops, bpf_mptcp_sched_ops.
> Register and unregister the bpf scheduler in .reg and .unreg.
> 
> This MPTCP BPF scheduler implementation is similar to BPF TCP CC. And
> net/ipv4/bpf_tcp_ca.c is a frame of reference for this patch.
> 
> Signed-off-by: Geliang Tang <geliang.tang@suse.com>
> ---
>  kernel/bpf/bpf_struct_ops_types.h |   4 +
>  net/mptcp/bpf.c                   | 154 ++++++++++++++++++++++++++++++
>  2 files changed, 158 insertions(+)
> 
> diff --git a/kernel/bpf/bpf_struct_ops_types.h b/kernel/bpf/bpf_struct_ops_types.h
> index 5678a9ddf817..5a6b0c0d8d3d 100644
> --- a/kernel/bpf/bpf_struct_ops_types.h
> +++ b/kernel/bpf/bpf_struct_ops_types.h
> @@ -8,5 +8,9 @@ BPF_STRUCT_OPS_TYPE(bpf_dummy_ops)
>  #ifdef CONFIG_INET
>  #include <net/tcp.h>
>  BPF_STRUCT_OPS_TYPE(tcp_congestion_ops)
> +#ifdef CONFIG_MPTCP
> +#include <net/mptcp.h>
> +BPF_STRUCT_OPS_TYPE(mptcp_sched_ops)
> +#endif
>  #endif
>  #endif
> diff --git a/net/mptcp/bpf.c b/net/mptcp/bpf.c
> index 535602ba2582..ad770deb5a72 100644
> --- a/net/mptcp/bpf.c
> +++ b/net/mptcp/bpf.c
> @@ -10,8 +10,162 @@
>  #define pr_fmt(fmt) "MPTCP: " fmt
>  
>  #include <linux/bpf.h>
> +#include <linux/bpf_verifier.h>
> +#include <linux/btf.h>
> +#include <linux/btf_ids.h>
>  #include "protocol.h"
>  
> +#ifdef CONFIG_BPF_JIT
> +extern struct bpf_struct_ops bpf_mptcp_sched_ops;
> +extern struct btf *btf_vmlinux;
> +static const struct btf_type *mptcp_sched_type __read_mostly;
> +static u32 mptcp_sched_id;
> +
> +static u32 optional_ops[] = {
> +	offsetof(struct mptcp_sched_ops, init),
> +	offsetof(struct mptcp_sched_ops, release),
> +	offsetof(struct mptcp_sched_ops, get_subflow),

I think that the 'get_subflow' member should not be options. Otherwise
the scheduler will useless, right ?!?

Otherwise LGTM.

Thanks!

Paolo