1 files changed, 29 insertions, 15 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 38633864a93e..ce8cbb29860b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -262,7 +262,7 @@ struct resv_map {
         struct list_head regions;
 };
 
-struct resv_map *resv_map_alloc(void)
+static struct resv_map *resv_map_alloc(void)
 {
         struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
         if (!resv_map)
@@ -274,7 +274,7 @@ struct resv_map *resv_map_alloc(void)
         return resv_map;
 }
 
-void resv_map_release(struct kref *ref)
+static void resv_map_release(struct kref *ref)
 {
         struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
 
@@ -289,7 +289,7 @@ static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
         if (!(vma->vm_flags & VM_SHARED))
                 return (struct resv_map *)(get_vma_private_data(vma) &
                                                         ~HPAGE_RESV_MASK);
-        return 0;
+        return NULL;
 }
 
 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
@@ -1459,11 +1459,11 @@ int hugetlb_report_meminfo(char *buf)
 {
         struct hstate *h = &default_hstate;
         return sprintf(buf,
-                        "HugePages_Total: %5lu\n"
-                        "HugePages_Free:  %5lu\n"
-                        "HugePages_Rsvd:  %5lu\n"
-                        "HugePages_Surp:  %5lu\n"
-                        "Hugepagesize:    %5lu kB\n",
+                        "HugePages_Total:   %5lu\n"
+                        "HugePages_Free:    %5lu\n"
+                        "HugePages_Rsvd:    %5lu\n"
+                        "HugePages_Surp:    %5lu\n"
+                        "Hugepagesize:   %8lu kB\n",
                         h->nr_huge_pages,
                         h->free_huge_pages,
                         h->resv_huge_pages,
@@ -1747,10 +1747,8 @@ void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
  * from other VMAs and let the children be SIGKILLed if they are faulting the
  * same region.
  */
-int unmap_ref_private(struct mm_struct *mm,
-                                        struct vm_area_struct *vma,
-                                        struct page *page,
-                                        unsigned long address)
+static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
+                                struct page *page, unsigned long address)
 {
         struct vm_area_struct *iter_vma;
         struct address_space *mapping;
@@ -2073,6 +2071,14 @@ follow_huge_pud(struct mm_struct *mm, unsigned long address,
         return NULL;
 }
 
+static int huge_zeropage_ok(pte_t *ptep, int write, int shared)
+{
+        if (!ptep || write || shared)
+                return 0;
+        else
+                return huge_pte_none(huge_ptep_get(ptep));
+}
+
 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
                         struct page **pages, struct vm_area_struct **vmas,
                         unsigned long *position, int *length, int i,
@@ -2082,6 +2088,8 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
         unsigned long vaddr = *position;
         int remainder = *length;
         struct hstate *h = hstate_vma(vma);
+        int zeropage_ok = 0;
+        int shared = vma->vm_flags & VM_SHARED;
 
         spin_lock(&mm->page_table_lock);
         while (vaddr < vma->vm_end && remainder) {
@@ -2094,8 +2102,11 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
                  * first, for the page indexing below to work.
                  */
                 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
+                if (huge_zeropage_ok(pte, write, shared))
+                        zeropage_ok = 1;
 
-                if (!pte || huge_pte_none(huge_ptep_get(pte)) ||
+                if (!pte ||
+                    (huge_pte_none(huge_ptep_get(pte)) && !zeropage_ok) ||
                     (write && !pte_write(huge_ptep_get(pte)))) {
                         int ret;
 
@@ -2115,8 +2126,11 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
                 page = pte_page(huge_ptep_get(pte));
 same_page:
                 if (pages) {
-                        get_page(page);
-                        pages[i] = page + pfn_offset;
+                        if (zeropage_ok)
+                                pages[i] = ZERO_PAGE(0);
+                        else
+                                pages[i] = page + pfn_offset;
+                        get_page(pages[i]);
                 }
 
                 if (vmas)