Support for recvmmsg / sendmmsg

Support for recvmmsg / sendmmsg

[Norman Maurer]

Hi there,

I am currently working on support for Datagrams in Netty using io_uring. One of the things that I noticed is that there is no recvmmsg / sendmmsg atm. You can argue that this may not be needed as I can jus submit multiple IORING_OP_* operations and so emulate it. While this is mostly true it would be still nice to have support for these calls because of:

* Issuing multiple IORING_OP_SENDMSG / RECVMSG is not the same as just issue one of them as I need to call io_uring_enter(…) earlier to ensure I not “overflow” the submission queue.
* Having multiple IORING_OP_SENDMSG / RECVMSG makes it more complicated in terms of keeping state in some cases

So would it be possible to add these ? For now I have implemented my own “batching” but its a way more complicated as I would love to :/

Thanks
Norman