[PATCH 0/6] x86/mem-paging: misc cleanup

[Jan Beulich <jbeulich@xxxxxxxx>]

Repeatedly looking at varying parts of this code has lead to
me accumulating a few adjustments.

1: fold p2m_mem_paging_prep()'s main if()-s
2: correct p2m_mem_paging_prep()'s error handling
3: use guest handle for XENMEM_paging_op_prep
4: add minimal lock order enforcement to p2m_mem_paging_prep()
5: move code to its dedicated source file
6: consistently use gfn_t

Jan