Revert "vhost_task: Allow vhost layer to use copy_process"

This reverts commit e297cd54b3f81d652456ae6cb93941fc6b5c6683.

Switching vhost workers to user workers broke existing workflows because
vhost workers started showing up in ps output breaking various scripts.
The reason is that vhost user workers are currently spawned as separate
processes and not as threads. Revert the patches converting vhost from
kthreads to vhost workers until vhost is ready to support user workers
created as actual threads.

Reported-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/all/aba6cca4-e66c-768f-375c-b38c8ba5e8a8@6wind.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
5 files changed