VMA_OP_FORK
VM_WARN_ON_ONCE(operation != VMA_OP_FORK && dst->vm_mm != src->vm_mm);
VM_WARN_ON_ONCE(operation != VMA_OP_FORK && src->anon_vma &&
if (operation == VMA_OP_FORK)
if (operation != VMA_OP_FORK)
rc = anon_vma_clone(vma, pvma, VMA_OP_FORK);