Shared dataspace problem

[Leon Brits]

Hi all,

I have a dataspace, reserved as pool 1 by dm_phys, which two tasks
shares. They synchronise access to the data by setting a lock at the
start of the dataspace with a cmpxchg-loop. All tasks map the dataspace
to their own VM area.

The problem is that if one of the tasks exists then the other would stop
with a page fault error the next time it accesses the shared dataspace.
Both of them where happily reading and writing to the dataspace at
exactly the place where the page fault occur.

Any suggestions?

Thanks
Leon