The rapid growth of io_uring

The rapid growth of io_uring

You don't have one pipe for all splices; you have one pipe per splice. If the first SQE copies 0x4000 bytes, then the linked SQE can only copy 0x4000 bytes out of the pipe, because there's only 0x4000 bytes in there to copy out. This is exactly what the kernel trick is - create a temporary pipe for the splice to use, so that you're always splicing in and out of pipes.