1 files changed, 58 insertions, 1 deletions

diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index d5878bed7841..8b1a2ce21ee5 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -1,6 +1,7 @@
 #include <linux/mm.h>
 #include <linux/highmem.h>
 #include <linux/sched.h>
+#include <linux/hugetlb.h>
 
 static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
                           struct mm_walk *walk)
@@ -79,6 +80,37 @@ static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end,
         return err;
 }
 
+#ifdef CONFIG_HUGETLB_PAGE
+static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr,
+                                       unsigned long end)
+{
+        unsigned long boundary = (addr & huge_page_mask(h)) + huge_page_size(h);
+        return boundary < end ? boundary : end;
+}
+
+static int walk_hugetlb_range(struct vm_area_struct *vma,
+                              unsigned long addr, unsigned long end,
+                              struct mm_walk *walk)
+{
+        struct hstate *h = hstate_vma(vma);
+        unsigned long next;
+        unsigned long hmask = huge_page_mask(h);
+        pte_t *pte;
+        int err = 0;
+
+        do {
+                next = hugetlb_entry_end(h, addr, end);
+                pte = huge_pte_offset(walk->mm, addr & hmask);
+                if (pte && walk->hugetlb_entry)
+                        err = walk->hugetlb_entry(pte, hmask, addr, next, walk);
+                if (err)
+                        return err;
+        } while (addr = next, addr != end);
+
+        return 0;
+}
+#endif
+
 /**
  * walk_page_range - walk a memory map's page tables with a callback
  * @mm: memory map to walk
@@ -107,6 +139,7 @@ int walk_page_range(unsigned long addr, unsigned long end,
         pgd_t *pgd;
         unsigned long next;
         int err = 0;
+        struct vm_area_struct *vma;
 
         if (addr >= end)
                 return err;
@@ -117,11 +150,34 @@ int walk_page_range(unsigned long addr, unsigned long end,
         pgd = pgd_offset(walk->mm, addr);
         do {
                 next = pgd_addr_end(addr, end);
+
+                /*
+                 * handle hugetlb vma individually because pagetable walk for
+                 * the hugetlb page is dependent on the architecture and
+                 * we can't handled it in the same manner as non-huge pages.
+                 */
+                vma = find_vma(walk->mm, addr);
+#ifdef CONFIG_HUGETLB_PAGE
+                if (vma && is_vm_hugetlb_page(vma)) {
+                        if (vma->vm_end < next)
+                                next = vma->vm_end;
+                        /*
+                         * Hugepage is very tightly coupled with vma, so
+                         * walk through hugetlb entries within a given vma.
+                         */
+                        err = walk_hugetlb_range(vma, addr, next, walk);
+                        if (err)
+                                break;
+                        pgd = pgd_offset(walk->mm, next);
+                        continue;
+                }
+#endif
                 if (pgd_none_or_clear_bad(pgd)) {
                         if (walk->pte_hole)
                                 err = walk->pte_hole(addr, next, walk);
                         if (err)
                                 break;
+                        pgd++;
                         continue;
                 }
                 if (walk->pgd_entry)
@@ -131,7 +187,8 @@ int walk_page_range(unsigned long addr, unsigned long end,
                         err = walk_pud_range(pgd, addr, next, walk);
                 if (err)
                         break;
-        } while (pgd++, addr = next, addr != end);
+                pgd++;
+        } while (addr = next, addr != end);
 
         return err;
 }