thp: move maybe_pmd_mkwrite() out of mk_huge_pmd()

thp: move maybe_pmd_mkwrite() out of mk_huge_pmd()

It's confusing that mk_huge_pmd() has semantics different from mk_pte() or
mk_pmd().  I spent some time on debugging issue cased by this
inconsistency.

Let's move maybe_pmd_mkwrite() out of mk_huge_pmd() and adjust prototype
to match mk_pte().

Signed-off-by: Kirill A. Shutemov <[email protected]>
Acked-by: Dave Hansen <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Wu Fengguang <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Hillf Danton <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>