2 files changed, 31 insertions, 19 deletions

diff --git a/Documentation/vm/pagemap.txt b/Documentation/vm/pagemap.txt
index 4600cbe3d6be..7587493c67f1 100644
--- a/Documentation/vm/pagemap.txt
+++ b/Documentation/vm/pagemap.txt
@@ -16,7 +16,7 @@ There are three components to pagemap:
     * Bits 0-4   swap type if swapped
     * Bits 5-54  swap offset if swapped
     * Bits 55-60 page shift (page size = 1<<page shift)
-    * Bit  61    reserved for future use
+    * Bit  61    page is file-page or shared-anon
     * Bit  62    page swapped
     * Bit  63    page present
 
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 83ede6e3b5ec..02476f5889f1 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -700,6 +700,7 @@ struct pagemapread {
 
 #define PM_PRESENT          PM_STATUS(4LL)
 #define PM_SWAP             PM_STATUS(2LL)
+#define PM_FILE             PM_STATUS(1LL)
 #define PM_NOT_PRESENT      PM_PSHIFT(PAGE_SHIFT)
 #define PM_END_OF_BUFFER    1
 
@@ -733,22 +734,33 @@ static int pagemap_pte_hole(unsigned long start, unsigned long end,
         return err;
 }
 
-static u64 swap_pte_to_pagemap_entry(pte_t pte)
+static void pte_to_pagemap_entry(pagemap_entry_t *pme,
+                struct vm_area_struct *vma, unsigned long addr, pte_t pte)
 {
-        swp_entry_t e = pte_to_swp_entry(pte);
-        return swp_type(e) | (swp_offset(e) << MAX_SWAPFILES_SHIFT);
-}
-
-static void pte_to_pagemap_entry(pagemap_entry_t *pme, pte_t pte)
-{
-        if (is_swap_pte(pte))
-                *pme = make_pme(PM_PFRAME(swap_pte_to_pagemap_entry(pte))
-                                | PM_PSHIFT(PAGE_SHIFT) | PM_SWAP);
-        else if (pte_present(pte))
-                *pme = make_pme(PM_PFRAME(pte_pfn(pte))
-                                | PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT);
-        else
+        u64 frame, flags;
+        struct page *page = NULL;
+
+        if (pte_present(pte)) {
+                frame = pte_pfn(pte);
+                flags = PM_PRESENT;
+                page = vm_normal_page(vma, addr, pte);
+        } else if (is_swap_pte(pte)) {
+                swp_entry_t entry = pte_to_swp_entry(pte);
+
+                frame = swp_type(entry) |
+                        (swp_offset(entry) << MAX_SWAPFILES_SHIFT);
+                flags = PM_SWAP;
+                if (is_migration_entry(entry))
+                        page = migration_entry_to_page(entry);
+        } else {
                 *pme = make_pme(PM_NOT_PRESENT);
+                return;
+        }
+
+        if (page && !PageAnon(page))
+                flags |= PM_FILE;
+
+        *pme = make_pme(PM_PFRAME(frame) | PM_PSHIFT(PAGE_SHIFT) | flags);
 }
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -815,7 +827,7 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
                 if (vma && (vma->vm_start <= addr) &&
                     !is_vm_hugetlb_page(vma)) {
                         pte = pte_offset_map(pmd, addr);
-                        pte_to_pagemap_entry(&pme, *pte);
+                        pte_to_pagemap_entry(&pme, vma, addr, *pte);
                         /* unmap before userspace copy */
                         pte_unmap(pte);
                 }
@@ -869,11 +881,11 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask,
  * For each page in the address space, this file contains one 64-bit entry
  * consisting of the following:
  *
- * Bits 0-55  page frame number (PFN) if present
+ * Bits 0-54  page frame number (PFN) if present
  * Bits 0-4   swap type if swapped
- * Bits 5-55  swap offset if swapped
+ * Bits 5-54  swap offset if swapped
  * Bits 55-60 page shift (page size = 1<<page shift)
- * Bit  61    reserved for future use
+ * Bit  61    page is file-page or shared-anon
  * Bit  62    page swapped
  * Bit  63    page present
  *