Re: [PATCH] io_uring: make OP_CLOSE consistent direct open

[Jens Axboe <axboe@kernel.dk>]

On 9/24/21 2:11 PM, Pavel Begunkov wrote:
> On 9/24/21 9:06 PM, Jens Axboe wrote:
>> On 9/24/21 1:57 PM, Jens Axboe wrote:
>>> On 9/24/21 1:04 PM, Pavel Begunkov wrote:
>>>> From recently open/accept are now able to manipulate fixed file table,
>>>> but it's inconsistent that close can't. Close the gap, keep API same as
>>>> with open/accept, i.e. via sqe->file_slot.
>>>
>>> I really think we should do this for 5.15 to make the API a bit more
>>> sane from the user point of view, folks definitely expect being able
>>> to use IORING_OP_CLOSE with a fixed file that they got with IORING_OP_OPEN,
>>> for example.
>>>
>>> How about this small tweak, basically making it follow the same rules
>>> as other commands that do fixed files:
>>>
>>> 1) Require IOSQE_FIXED_FILE to be set for a direct close. sqe->file_index
>>>    will be the descriptor to close in that case. If sqe->fd is set, we
>>>    -EINVAL the request.
>>>
>>> 2) If IOSQE_FIXED_FILE isn't set, it's a normal close. As before, if
>>>    sqe->file_index is set and IOSQE_FIXED_FILE isn't, then we -EINVAL
>>>    the request.
>>>
>>> Basically this incremental on top of yours.
>>
>> Hmm, we don't require that for open or accept. Why not? Seems a bit
>> counter intuitive. But maybe it's better we do this one as-is, and then
> 
> Accept takes a fd as an argument and so IOSQE_FIXED_FILE already applies
> to it and can't be used as described. Close is just made consistent with
> the rest.

What I'm saying is why don't we make IOSQE_FIXED_FILE for open/accept
consistent as well?

-- 
Jens Axboe