+#ifdef CONFIG_HAVE_MOVE_PUD
+static bool move_normal_pud(struct vm_area_struct *vma, unsigned long old_addr,
+ unsigned long new_addr, pud_t *old_pud, pud_t *new_pud)
+{
+ spinlock_t *old_ptl, *new_ptl;
+ struct mm_struct *mm = vma->vm_mm;
+ pud_t pud;
+
+ /*
+ * The destination pud shouldn't be established, free_pgtables()
+ * should have released it.
+ */
+ if (WARN_ON_ONCE(!pud_none(*new_pud)))
+ return false;
+
+ /*
+ * We don't have to worry about the ordering of src and dst
+ * ptlocks because exclusive mmap_lock prevents deadlock.
+ */
+ old_ptl = pud_lock(vma->vm_mm, old_pud);
+ new_ptl = pud_lockptr(mm, new_pud);
+ if (new_ptl != old_ptl)
+ spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
+
+ /* Clear the pud */
+ pud = *old_pud;
+ pud_clear(old_pud);
+
+ VM_BUG_ON(!pud_none(*new_pud));
+
+ /* Set the new pud */
+ set_pud_at(mm, new_addr, new_pud, pud);
+ flush_tlb_range(vma, old_addr, old_addr + PUD_SIZE);
+ if (new_ptl != old_ptl)
+ spin_unlock(new_ptl);
+ spin_unlock(old_ptl);
+
+ return true;
+}
+#else
+static inline bool move_normal_pud(struct vm_area_struct *vma,
+ unsigned long old_addr, unsigned long new_addr, pud_t *old_pud,
+ pud_t *new_pud)
+{
+ return false;
+}
+#endif
+
+enum pgt_entry {
+ NORMAL_PMD,
+ HPAGE_PMD,
+ NORMAL_PUD,
+};
+
+/*
+ * Returns an extent of the corresponding size for the pgt_entry specified if
+ * valid. Else returns a smaller extent bounded by the end of the source and
+ * destination pgt_entry.
+ */
+static unsigned long get_extent(enum pgt_entry entry, unsigned long old_addr,
+ unsigned long old_end, unsigned long new_addr)
+{
+ unsigned long next, extent, mask, size;
+
+ switch (entry) {
+ case HPAGE_PMD:
+ case NORMAL_PMD:
+ mask = PMD_MASK;
+ size = PMD_SIZE;
+ break;
+ case NORMAL_PUD:
+ mask = PUD_MASK;
+ size = PUD_SIZE;
+ break;
+ default:
+ BUILD_BUG();
+ break;
+ }
+
+ next = (old_addr + size) & mask;
+ /* even if next overflowed, extent below will be ok */
+ extent = (next > old_end) ? old_end - old_addr : next - old_addr;
+ next = (new_addr + size) & mask;
+ if (extent > next - new_addr)
+ extent = next - new_addr;
+ return extent;
+}
+
+/*
+ * Attempts to speedup the move by moving entry at the level corresponding to
+ * pgt_entry. Returns true if the move was successful, else false.
+ */
+static bool move_pgt_entry(enum pgt_entry entry, struct vm_area_struct *vma,
+ unsigned long old_addr, unsigned long new_addr,
+ void *old_entry, void *new_entry, bool need_rmap_locks)
+{
+ bool moved = false;
+
+ /* See comment in move_ptes() */
+ if (need_rmap_locks)
+ take_rmap_locks(vma);
+
+ switch (entry) {
+ case NORMAL_PMD:
+ moved = move_normal_pmd(vma, old_addr, new_addr, old_entry,
+ new_entry);
+ break;
+ case NORMAL_PUD:
+ moved = move_normal_pud(vma, old_addr, new_addr, old_entry,
+ new_entry);
+ break;
+ case HPAGE_PMD:
+ moved = IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
+ move_huge_pmd(vma, old_addr, new_addr, old_entry,
+ new_entry);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ break;
+ }
+
+ if (need_rmap_locks)
+ drop_rmap_locks(vma);
+
+ return moved;
+}
+