bad math: it does not handle page-boundary conditions, and will not
end up mapping all of the requested addresses. This will cause a panic:
page fault during probe on some systems. I have a machine that will
panic every time (when using the dpt driver) on kernel probe when there
are 5 drives installed. When there are 4 drives, it is fine.
Fix is to always allocate/deallocate an extra page.
There is also a bonus splx() fix on an early error return.
Submitted by: Mark J. Taylor <mtaylor@cybernet.com>
PR: 9367
8cb4373141