The vmalloc operation is split into two pieces:  allocate the backing
pages and map them into the kernel page tabels for virtually contingous
access. (Same for vfree).  A new set of interfaces, vmap & vunmap does
only the second part and thus allows mapping arbitray pages into 
kernel virtual memory.

The vmalloc.c internals have been completly overhauled to support this,
but the exported interfaces are unchanged.