1 files changed, 29 insertions, 3 deletions

diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index 03761577ae86..60f7856e508f 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -69,14 +69,14 @@ again:
         return err;
 }
 
-static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end,
+static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
                           struct mm_walk *walk)
 {
         pud_t *pud;
         unsigned long next;
         int err = 0;
 
-        pud = pud_offset(pgd, addr);
+        pud = pud_offset(p4d, addr);
         do {
  again:
                 next = pud_addr_end(addr, end);
@@ -113,6 +113,32 @@ static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end,
         return err;
 }
 
+static int walk_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
+                          struct mm_walk *walk)
+{
+        p4d_t *p4d;
+        unsigned long next;
+        int err = 0;
+
+        p4d = p4d_offset(pgd, addr);
+        do {
+                next = p4d_addr_end(addr, end);
+                if (p4d_none_or_clear_bad(p4d)) {
+                        if (walk->pte_hole)
+                                err = walk->pte_hole(addr, next, walk);
+                        if (err)
+                                break;
+                        continue;
+                }
+                if (walk->pmd_entry || walk->pte_entry)
+                        err = walk_pud_range(p4d, addr, next, walk);
+                if (err)
+                        break;
+        } while (p4d++, addr = next, addr != end);
+
+        return err;
+}
+
 static int walk_pgd_range(unsigned long addr, unsigned long end,
                           struct mm_walk *walk)
 {
@@ -131,7 +157,7 @@ static int walk_pgd_range(unsigned long addr, unsigned long end,
                         continue;
                 }
                 if (walk->pmd_entry || walk->pte_entry)
-                        err = walk_pud_range(pgd, addr, next, walk);
+                        err = walk_p4d_range(pgd, addr, next, walk);
                 if (err)
                         break;
         } while (pgd++, addr = next, addr != end);