3 files changed, 46 insertions, 32 deletions

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index a05a669510a4..070553427dd5 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -662,31 +662,18 @@ static u64 huge_pte_to_pagemap_entry(pte_t pte, int offset)
         return pme;
 }
 
-static int pagemap_hugetlb_range(pte_t *pte, unsigned long addr,
-                                 unsigned long end, struct mm_walk *walk)
+/* This function walks within one hugetlb entry in the single call */
+static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask,
+                                 unsigned long addr, unsigned long end,
+                                 struct mm_walk *walk)
 {
-        struct vm_area_struct *vma;
         struct pagemapread *pm = walk->private;
-        struct hstate *hs = NULL;
         int err = 0;
+        u64 pfn;
 
-        vma = find_vma(walk->mm, addr);
-        if (vma)
-                hs = hstate_vma(vma);
         for (; addr != end; addr += PAGE_SIZE) {
-                u64 pfn = PM_NOT_PRESENT;
-
-                if (vma && (addr >= vma->vm_end)) {
-                        vma = find_vma(walk->mm, addr);
-                        if (vma)
-                                hs = hstate_vma(vma);
-                }
-
-                if (vma && (vma->vm_start <= addr) && is_vm_hugetlb_page(vma)) {
-                        /* calculate pfn of the "raw" page in the hugepage. */
-                        int offset = (addr & ~huge_page_mask(hs)) >> PAGE_SHIFT;
-                        pfn = huge_pte_to_pagemap_entry(*pte, offset);
-                }
+                int offset = (addr & ~hmask) >> PAGE_SHIFT;
+                pfn = huge_pte_to_pagemap_entry(*pte, offset);
                 err = add_to_pagemap(addr, pfn, pm);
                 if (err)
                         return err;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e70f21beb4b4..462acaf36f3a 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -783,8 +783,8 @@ struct mm_walk {
         int (*pmd_entry)(pmd_t *, unsigned long, unsigned long, struct mm_walk *);
         int (*pte_entry)(pte_t *, unsigned long, unsigned long, struct mm_walk *);
         int (*pte_hole)(unsigned long, unsigned long, struct mm_walk *);
-        int (*hugetlb_entry)(pte_t *, unsigned long, unsigned long,
-                             struct mm_walk *);
+        int (*hugetlb_entry)(pte_t *, unsigned long,
+                             unsigned long, unsigned long, struct mm_walk *);
         struct mm_struct *mm;
         void *private;
 };
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index 7b47a57b6646..8b1a2ce21ee5 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -80,6 +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
@@ -128,20 +159,16 @@ int walk_page_range(unsigned long addr, unsigned long end,
                 vma = find_vma(walk->mm, addr);
 #ifdef CONFIG_HUGETLB_PAGE
                 if (vma && is_vm_hugetlb_page(vma)) {
-                        pte_t *pte;
-                        struct hstate *hs;
-
                         if (vma->vm_end < next)
                                 next = vma->vm_end;
-                        hs = hstate_vma(vma);
-                        pte = huge_pte_offset(walk->mm,
-                                              addr & huge_page_mask(hs));
-                        if (pte && !huge_pte_none(huge_ptep_get(pte))
-                            && walk->hugetlb_entry)
-                                err = walk->hugetlb_entry(pte, addr,
-                                                          next, walk);
+                        /*
+                         * 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