1 files changed, 29 insertions, 0 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 20117a4b8ab6..783098f6cf8e 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -565,3 +565,32 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
 
         return i;
 }
+
+void hugetlb_change_protection(struct vm_area_struct *vma,
+                unsigned long address, unsigned long end, pgprot_t newprot)
+{
+        struct mm_struct *mm = vma->vm_mm;
+        unsigned long start = address;
+        pte_t *ptep;
+        pte_t pte;
+
+        BUG_ON(address >= end);
+        flush_cache_range(vma, address, end);
+
+        spin_lock(&mm->page_table_lock);
+        for (; address < end; address += HPAGE_SIZE) {
+                ptep = huge_pte_offset(mm, address);
+                if (!ptep)
+                        continue;
+                if (!pte_none(*ptep)) {
+                        pte = huge_ptep_get_and_clear(mm, address, ptep);
+                        pte = pte_mkhuge(pte_modify(pte, newprot));
+                        set_huge_pte_at(mm, address, ptep, pte);
+                        lazy_mmu_prot_update(pte);
+                }
+        }
+        spin_unlock(&mm->page_table_lock);
+
+        flush_tlb_range(vma, start, end);
+}
+