On 07/11/2020 13:46, Stefan Metzmacher wrote:
> Hi Pavel,
>
>> We don't even allow not plain data msg_control, which is disallowed in __sys_{send,revb}msg_sock().
>
> Can't we better remove these checks and allow msg_control?
> For me it's a limitation that I would like to be removed.
We can grab fs only in specific situations as you mentioned, by e.g.
adding a switch(opcode) in io_prep_async_work(), but that's the easy
part. All msg_control should be dealt one by one as they do different
things. And it's not the fact that they ever require fs.
>
> If there's a cost using IO_WQ_WORK_FS, would it be possible to use IO_WQ_WORK_FS only it msg_control is actually use>
> if (msg->msg_control || msg->msg_controllen)
> static const struct io_op_def sendmsg_control_op_def = {
> ...
> };
>
> something = &sendmsg_control_op_def;
> }
--
Pavel Begunkov
