Re: [PATCH v3 sysctl-next] bpf: move bpf sysctls from kernel/sysctl.c to bpf module

[Daniel Borkmann <daniel@iogearbox.net>]

On 3/2/22 9:39 PM, Luis Chamberlain wrote:
> On Wed, Mar 02, 2022 at 10:04:12AM +0800, Yan Zhu wrote:
>> We're moving sysctls out of kernel/sysctl.c as its a mess. We
>> already moved all filesystem sysctls out. And with time the goal is
>> to move all sysctls out to their own susbsystem/actual user.
>>
>> kernel/sysctl.c has grown to an insane mess and its easy to run
>> into conflicts with it. The effort to move them out is part of this.
>>
>> Signed-off-by: Yan Zhu <zhuyan34@huawei.com>
> 
> Daniel, let me know if this makes more sense now, and if so I can
> offer take it through sysctl-next to avoid conflicts more sysctl knobs
> get moved out from kernel/sysctl.c.

If this is a whole ongoing effort rather than drive-by patch, then it's
fine with me. Btw, the patch itself should also drop the linux/bpf.h
include from kernel/sysctl.c since nothing else is using it after the
patch.

Btw, related to cleanups.. historically, we have a bunch of other knobs
for BPF under net (in net_core_table), that is:

   /proc/sys/net/core/bpf_jit_enable
   /proc/sys/net/core/bpf_jit_harden
   /proc/sys/net/core/bpf_jit_kallsyms
   /proc/sys/net/core/bpf_jit_limit

Would be nice to consolidate all under e.g. /proc/sys/kernel/bpf_* for
future going forward, and technically, they should be usable also w/o
net configured into kernel. Is there infra to point the sysctl knobs
e.g. under net/core/ to kernel/, or best way would be to have single
struct ctl_table and register for both?

Cheers,
Daniel