Re: [PATCH for-next v2 10/25] io_uring: kill REQ_F_COMPLETE_INLINE

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

On 6/15/22 09:20, Hao Xu wrote:
> On 6/14/22 22:37, Pavel Begunkov wrote:
>> REQ_F_COMPLETE_INLINE is only needed to delay queueing into the
>> completion list to io_queue_sqe() as __io_req_complete() is inlined and
>> we don't want to bloat the kernel.
>>
>> As now we complete in a more centralised fashion in io_issue_sqe() we
>> can get rid of the flag and queue to the list directly.
>>
>> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
>> ---
>>   io_uring/io_uring.c       | 20 ++++++++------------
>>   io_uring/io_uring.h       |  5 -----
>>   io_uring/io_uring_types.h |  3 ---
>>   3 files changed, 8 insertions(+), 20 deletions(-)
>>
>> diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
>> index 1fb93fdcfbab..fcee58c6c35e 100644
>> --- a/io_uring/io_uring.c
>> +++ b/io_uring/io_uring.c
>> @@ -1278,17 +1278,14 @@ static void io_req_complete_post32(struct io_kiocb *req, u64 extra1, u64 extra2)
>>   inline void __io_req_complete(struct io_kiocb *req, unsigned issue_flags)
>>   {
>> -    if (issue_flags & IO_URING_F_COMPLETE_DEFER)
>> -        io_req_complete_state(req);
>> -    else
>> -        io_req_complete_post(req);
>> +    io_req_complete_post(req);
>>   }
> 
> io_read/write and provide_buffers/remove_buffers are still using
> io_req_complete() in their own function. By removing the
> IO_URING_F_COMPLETE_DEFER branch they will end in complete_post path
> 100% which we shouldn't.

Old provided buffers are such a useful feature that Jens adds
a new ring-based version of it, so I couldn't care less about
those two.

I any case, let's leave it to follow ups. Those locking is a
weird construct and shouldn't be done this ad-hook way, it's
a potential bug nest

-- 
Pavel Begunkov