The rapid growth of io_uring

right so this is obviously a huge problem, it makes anything more than a toy server impossible. I don't understand the reasoning for this limitation?

A buffer per operation is also a nonstarter for the same reason. In 5.7 IOSQE_BUFFER_SELECT attempts to solve the buffer problem with rotations. But I think an input / output ring buffer solution that allows allocation at the tail when needed, and just returns ranges into the input or output buffer makes more sense?