Re: [RFC PATCH bpf-next 0/5] net/smc: Introduce BPF injection capability

["D. Wythe" <alibuda@linux.alibaba.com>]

Hi everyone,

It's seems the RFC patch been hanging for some time.  I would like to 
politely inquire if there are any suggestions or criticisms.
Compared to previous patches, this patch has several main features:

1. Allow registration of multiple negotiators, each SMC negotiator has a 
name and can be indexed that name
2. no read/write lock anymore
3. support bpf update

If you have any suggestions or criticisms, please let me know.

Thanks
D. Wythe

On 4/6/23 11:30 PM, D. Wythe wrote:
> From: "D. Wythe" <alibuda@linux.alibaba.com>
>
> This patches attempt to introduce BPF injection capability for SMC,
> and add selftest to ensure code stability.
>
> As we all know that the SMC protocol is not suitable for all scenarios,
> especially for short-lived. However, for most applications, they cannot
> guarantee that there are no such scenarios at all. Therefore, apps
> may need some specific strategies to decide shall we need to use SMC
> or not, for example, apps can limit the scope of the SMC to a specific
> IP address or port.
>
> Based on the consideration of transparent replacement, we hope that apps
> can remain transparent even if they need to formulate some specific
> strategies for SMC using. That is, do not need to recompile their code.
>
> On the other hand, we need to ensure the scalability of strategies
> implementation. Although it is simple to use socket options or sysctl,
> it will bring more complexity to subsequent expansion.
>
> Fortunately, BPF can solve these concerns very well, users can write
> thire own strategies in eBPF to choose whether to use SMC or not.
> And it's quite easy for them to modify their strategies in the future.
>
> This patches implement injection capability for SMC via struct_ops.
> In that way, we can add new injection scenarios in the future.
>
> D. Wythe (5):
>    net/smc: move smc_sock related structure definition
>    net/smc: net/smc: allow smc to negotiate protocols on policies
>    net/smc: allow set or get smc negotiator by sockopt
>    bpf: add smc negotiator support in BPF struct_ops
>    bpf/selftests: add selftest for SMC bpf capability
>
>   include/net/smc.h                                | 268 +++++++++++++++++
>   include/uapi/linux/smc.h                         |   1 +
>   kernel/bpf/bpf_struct_ops_types.h                |   4 +
>   net/Makefile                                     |   1 +
>   net/smc/Kconfig                                  |  13 +
>   net/smc/af_smc.c                                 | 203 ++++++++++---
>   net/smc/bpf_smc.c                                | 359 +++++++++++++++++++++++
>   net/smc/smc.h                                    | 224 --------------
>   tools/testing/selftests/bpf/prog_tests/bpf_smc.c | 107 +++++++
>   tools/testing/selftests/bpf/progs/bpf_smc.c      | 265 +++++++++++++++++
>   10 files changed, 1186 insertions(+), 259 deletions(-)
>   create mode 100644 net/smc/bpf_smc.c
>   create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_smc.c
>   create mode 100644 tools/testing/selftests/bpf/progs/bpf_smc.c
>