huge_pte_mkwrite
WARN_ON(!huge_pte_write(huge_pte_mkwrite(huge_pte_wrprotect(pte))));
WARN_ON(huge_pte_write(huge_pte_wrprotect(huge_pte_mkwrite(pte))));
entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(vma->vm_mm, address, ptep)));