thp: introduce hugepage_vma_check()

commit fa475e517adb422cb3492e636195f9b2c0d009c8 upstream.

Multiple places do the same check.

Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Ni zhan Chen <nizhan.chen@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2:
 - Also move the is_linear_pfn_mapping() test
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 79166c2..d570aae 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1817,6 +1817,24 @@ static void __collapse_huge_page_copy(pte_t *pte, struct page *page,
        }
 }
 
+static bool hugepage_vma_check(struct vm_area_struct *vma)
+{
+       if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) ||
+           (vma->vm_flags & VM_NOHUGEPAGE))
+               return false;
+
+       if (!vma->anon_vma || vma->vm_ops)
+               return false;
+       if (is_vma_temporary_stack(vma))
+               return false;
+       /*
+        * 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);
+       return true;
+}
+
 static void collapse_huge_page(struct mm_struct *mm,
                               unsigned long address,
                               struct page **hpage,
@@ -1889,21 +1907,8 @@ static void collapse_huge_page(struct mm_struct *mm,
        hend = vma->vm_end & HPAGE_PMD_MASK;
        if (address < hstart || address + HPAGE_PMD_SIZE > hend)
                goto out;
-
-       if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) ||
-           (vma->vm_flags & VM_NOHUGEPAGE))
+       if (!hugepage_vma_check(vma))
                goto out;
-
-       if (!vma->anon_vma || vma->vm_ops)
-               goto out;
-       if (is_vma_temporary_stack(vma))
-               goto out;
-       /*
-        * 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))
                goto out;
@@ -2133,25 +2138,11 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
                        progress++;
                        break;
                }
-
-               if ((!(vma->vm_flags & VM_HUGEPAGE) &&
-                    !khugepaged_always()) ||
-                   (vma->vm_flags & VM_NOHUGEPAGE)) {
-               skip:
+               if (!hugepage_vma_check(vma)) {
+skip:
                        progress++;
                        continue;
                }
-               if (!vma->anon_vma || vma->vm_ops)
-                       goto skip;
-               if (is_vma_temporary_stack(vma))
-                       goto skip;
-               /*
-                * 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)