Preempting kernel tasks

Jason Burrell (
Tue, 3 Sep 1996 07:33:23 -0500 (CDT)

Forgive me for my ignorance, but how can a kernel task be preempted? The
situation concerns the loopback device. Basically, it's set up so that calls
to an encrypted filesystem run through an encryption/decryption process in
the kernel. Unfortunately, the system literally stops when this routine is
called, because it's time consuming.

What I want to know is how to safely halt that entire call (the file
operation and its call to the cryptographic functions), allow the kernel to
do some other work, and then come back. If this can't be done, encryption is
fairly useless as a kernel level task.