maps4: introduce a generic page walker

Introduce a general page table walker

Signed-off-by: Matt Mackall <mpm@selenic.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index bcbe6979ff65..89d7c691b93a 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -718,6 +718,28 @@ unsigned long unmap_vmas(struct mmu_gather **tlb,
                 struct vm_area_struct *start_vma, unsigned long start_addr,
                 unsigned long end_addr, unsigned long *nr_accounted,
                 struct zap_details *);
+
+/**
+ * mm_walk - callbacks for walk_page_range
+ * @pgd_entry: if set, called for each non-empty PGD (top-level) entry
+ * @pud_entry: if set, called for each non-empty PUD (2nd-level) entry
+ * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry
+ * @pte_entry: if set, called for each non-empty PTE (4th-level) entry
+ * @pte_hole: if set, called for each hole at all levels
+ *
+ * (see walk_page_range for more details)
+ */
+struct mm_walk {
+        int (*pgd_entry)(pgd_t *, unsigned long, unsigned long, void *);
+        int (*pud_entry)(pud_t *, unsigned long, unsigned long, void *);
+        int (*pmd_entry)(pmd_t *, unsigned long, unsigned long, void *);
+        int (*pte_entry)(pte_t *, unsigned long, unsigned long, void *);
+        int (*pte_hole)(unsigned long, unsigned long, void *);
+};
+
+int walk_page_range(const struct mm_struct *, unsigned long addr,
+                    unsigned long end, const struct mm_walk *walk,
+                    void *private);
 void free_pgd_range(struct mmu_gather **tlb, unsigned long addr,
                 unsigned long end, unsigned long floor, unsigned long ceiling);
 void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *start_vma,