userfaultfd_remove 69 include/linux/userfaultfd_k.h extern bool userfaultfd_remove(struct vm_area_struct *vma, userfaultfd_remove 769 mm/madvise.c if (!userfaultfd_remove(vma, start, end)) { userfaultfd_remove 852 mm/madvise.c if (userfaultfd_remove(vma, start, end)) {