Re: [RFC v2 00/23] io_uring BPF requests

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

On 5/21/21 1:35 AM, Song Liu wrote:
>> On May 19, 2021, at 7:13 AM, Pavel Begunkov <asml.silence@gmail.com> wrote:
>> The main problem solved is feeding completion information of other
>> requests in a form of CQEs back into BPF. I decided to wire up support
>> for multiple completion queues (aka CQs) and give BPF programs access to
>> them, so leaving userspace in control over synchronisation that should
>> be much more flexible that the link-based approach.
>>
>> For instance, there can be a separate CQ for each BPF program, so no
>> extra sync is needed, and communication can be done by submitting a
>> request targeting a neighboring CQ or submitting a CQE there directly
>> (see test3 below). CQ is choosen by sqe->cq_idx, so everyone can
>> cross-fire if willing.
>>
> 
> [...]
> 
>>  bpf: add IOURING program type
>>  io_uring: implement bpf prog registration
>>  io_uring: add support for bpf requests
>>  io_uring: enable BPF to submit SQEs
>>  io_uring: enable bpf to submit CQEs
>>  io_uring: enable bpf to reap CQEs
>>  libbpf: support io_uring
>>  io_uring: pass user_data to bpf executor
>>  bpf: Add bpf_copy_to_user() helper
>>  io_uring: wire bpf copy to user
>>  io_uring: don't wait on CQ exclusively
>>  io_uring: enable bpf reqs to wait for CQs
> 
> Besides the a few comments, these BPF related patches look sane to me. 
> Please consider add some selftests (tools/testing/selftests/bpf). 

The comments are noted. Thanks Song

-- 
Pavel Begunkov