Re: [PATCH v3 07/10] io_uring/bpf: implement struct_ops registration

[Pavel Begunkov <asml.silence@gmail.com>]

On 11/24/25 14:29, Ming Lei wrote:
> On Mon, Nov 24, 2025 at 01:12:29PM +0000, Pavel Begunkov wrote:
>> On 11/24/25 03:44, Ming Lei wrote:
>>> On Thu, Nov 13, 2025 at 11:59:44AM +0000, Pavel Begunkov wrote:
...
>>> I feel per-io-uring struct_ops is less useful, because it means the io_uring
>>> application has to be capable of loading/registering struct_ops prog, which
>>> often needs privilege.
>>
>> I gave it a thought before, there would need to be a way to pass a
>> program from one (e.g. privileged) task to another, e.g. by putting
>> it into a list on attachment from where it can be imported. That
>> can be extended, and I needed to start somewhere.
> 
> If any task can ask such privileged task to load bpf program for itself,
> BPF_UNPRIV_DEFAULT_OFF becomes `N` actually for bpf controlled io_uring.

That's not what I said. There are enough apps that can have a
privileged component but caps are not extended to e.g. IO
workers.

>>> For example of IO link use case you mentioned, why does the application need
>>> to get privilege for running IO link?
>>
>> Links are there to compare with existing features. It's more interesting
>> to allow arbitrary relations / result propagation between requests. Maybe
>> some common patterns can be generalised, but otherwise nothing can be
>> done with this without custom tailored bpf programs.
> 
> I know the motivation, which is one thing covered in my IORING_OP_BPF patch
> too.
-- 
Pavel Begunkov