I know how to wait in Linux kernel queues using wait_event and how to wake them up.
Now I need to figure out how to wait in multiple queues at once. I need to multiplex multiple event sources, basically in a way similar to poll or select, but since the sources of events don't have the form of a pollable file descriptor, I wasn't able to find inspiration in the implementation of these syscalls.
My initial idea was to take the code from the wait_event macro, use DEFINE_WAIT multiple times as well as prepare_to_wait.
However, given how prepare_to_wait is implemented, I'm afraid the internal linked list of the queue would become corrupted if the same "waiter" is added multiple times (which could maybe happen if one queue causes wakeup, but the wait condition isn't met and waiting is being restarted).