3 files changed, 27 insertions, 21 deletions

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index df29c8fde36b..8847c8c29791 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -117,7 +117,7 @@ static inline void vma_adjust_trans_huge(struct vm_area_struct *vma,
                                          unsigned long end,
                                          long adjust_next)
 {
-        if (!vma->anon_vma || vma->vm_ops || vma->vm_file)
+        if (!vma->anon_vma || vma->vm_ops)
                 return;
         __vma_adjust_trans_huge(vma, start, end, adjust_next);
 }
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 692dbae6ffa7..2348db26bc3d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -137,7 +137,8 @@ extern unsigned int kobjsize(const void *objp);
 #define VM_RandomReadHint(v)            ((v)->vm_flags & VM_RAND_READ)
 
 /*
- * special vmas that are non-mergable, non-mlock()able
+ * Special vmas that are non-mergable, non-mlock()able.
+ * Note: mm/huge_memory.c VM_NO_THP depends on this definition.
  */
 #define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
 
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 470dcda10add..83326ad66d9b 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1408,6 +1408,9 @@ out:
         return ret;
 }
 
+#define VM_NO_THP (VM_SPECIAL|VM_INSERTPAGE|VM_MIXEDMAP|VM_SAO| \
+                   VM_HUGETLB|VM_SHARED|VM_MAYSHARE)
+
 int hugepage_madvise(struct vm_area_struct *vma,
                      unsigned long *vm_flags, int advice)
 {
@@ -1416,11 +1419,7 @@ int hugepage_madvise(struct vm_area_struct *vma,
                 /*
                  * Be somewhat over-protective like KSM for now!
                  */
-                if (*vm_flags & (VM_HUGEPAGE |
-                                 VM_SHARED   | VM_MAYSHARE   |
-                                 VM_PFNMAP   | VM_IO      | VM_DONTEXPAND |
-                                 VM_RESERVED | VM_HUGETLB | VM_INSERTPAGE |
-                                 VM_MIXEDMAP | VM_SAO))
+                if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP))
                         return -EINVAL;
                 *vm_flags &= ~VM_NOHUGEPAGE;
                 *vm_flags |= VM_HUGEPAGE;
@@ -1436,11 +1435,7 @@ int hugepage_madvise(struct vm_area_struct *vma,
                 /*
                  * Be somewhat over-protective like KSM for now!
                  */
-                if (*vm_flags & (VM_NOHUGEPAGE |
-                                 VM_SHARED   | VM_MAYSHARE   |
-                                 VM_PFNMAP   | VM_IO      | VM_DONTEXPAND |
-                                 VM_RESERVED | VM_HUGETLB | VM_INSERTPAGE |
-                                 VM_MIXEDMAP | VM_SAO))
+                if (*vm_flags & (VM_NOHUGEPAGE | VM_NO_THP))
                         return -EINVAL;
                 *vm_flags &= ~VM_HUGEPAGE;
                 *vm_flags |= VM_NOHUGEPAGE;
@@ -1574,10 +1569,14 @@ int khugepaged_enter_vma_merge(struct vm_area_struct *vma)
                  * page fault if needed.
                  */
                 return 0;
-        if (vma->vm_file || vma->vm_ops)
+        if (vma->vm_ops)
                 /* khugepaged not yet working on file or special mappings */
                 return 0;
-        VM_BUG_ON(is_linear_pfn_mapping(vma) || is_pfn_mapping(vma));
+        /*
+         * If is_pfn_mapping() is true is_learn_pfn_mapping() must be
+         * true too, verify it here.
+         */
+        VM_BUG_ON(is_linear_pfn_mapping(vma) || vma->vm_flags & VM_NO_THP);
         hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
         hend = vma->vm_end & HPAGE_PMD_MASK;
         if (hstart < hend)
@@ -1828,12 +1827,15 @@ static void collapse_huge_page(struct mm_struct *mm,
             (vma->vm_flags & VM_NOHUGEPAGE))
                 goto out;
 
-        /* VM_PFNMAP vmas may have vm_ops null but vm_file set */
-        if (!vma->anon_vma || vma->vm_ops || vma->vm_file)
+        if (!vma->anon_vma || vma->vm_ops)
                 goto out;
         if (is_vma_temporary_stack(vma))
                 goto out;
-        VM_BUG_ON(is_linear_pfn_mapping(vma) || is_pfn_mapping(vma));
+        /*
+         * If is_pfn_mapping() is true is_learn_pfn_mapping() must be
+         * true too, verify it here.
+         */
+        VM_BUG_ON(is_linear_pfn_mapping(vma) || vma->vm_flags & VM_NO_THP);
 
         pgd = pgd_offset(mm, address);
         if (!pgd_present(*pgd))
@@ -2066,13 +2068,16 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
                         progress++;
                         continue;
                 }
-                /* VM_PFNMAP vmas may have vm_ops null but vm_file set */
-                if (!vma->anon_vma || vma->vm_ops || vma->vm_file)
+                if (!vma->anon_vma || vma->vm_ops)
                         goto skip;
                 if (is_vma_temporary_stack(vma))
                         goto skip;
-
-                VM_BUG_ON(is_linear_pfn_mapping(vma) || is_pfn_mapping(vma));
+                /*
+                 * If is_pfn_mapping() is true is_learn_pfn_mapping()
+                 * must be true too, verify it here.
+                 */
+                VM_BUG_ON(is_linear_pfn_mapping(vma) ||
+                          vma->vm_flags & VM_NO_THP);
 
                 hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
                 hend = vma->vm_end & HPAGE_PMD_MASK;