mm,thp: reduce ifdef'ery for THP in generic code

- pgtable-generic.c: Fold individual #ifdef for each helper into a top
  level #ifdef. Makes code more readable

- Converted the stub helpers for !THP to BUILD_BUG() vs. runtime BUG()

Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: http://lkml.kernel.org/r/20151009133450.GA8597@node
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

1 files changed, 3 insertions, 21 deletions

diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index 48851894e699..c9c59bb75a17 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -82,12 +82,13 @@ pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
 }
 #endif
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+
 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
 int pmdp_set_access_flags(struct vm_area_struct *vma,
                           unsigned long address, pmd_t *pmdp,
                           pmd_t entry, int dirty)
 {
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
         int changed = !pmd_same(*pmdp, entry);
         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
         if (changed) {
@@ -95,10 +96,6 @@ int pmdp_set_access_flags(struct vm_area_struct *vma,
                 flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
         }
         return changed;
-#else /* CONFIG_TRANSPARENT_HUGEPAGE */
-        BUG();
-        return 0;
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 }
 #endif
 
@@ -107,11 +104,7 @@ int pmdp_clear_flush_young(struct vm_area_struct *vma,
                            unsigned long address, pmd_t *pmdp)
 {
         int young;
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
-#else
-        BUG();
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
         young = pmdp_test_and_clear_young(vma, address, pmdp);
         if (young)
                 flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
@@ -120,7 +113,6 @@ int pmdp_clear_flush_young(struct vm_area_struct *vma,
 #endif
 
 #ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
                             pmd_t *pmdp)
 {
@@ -131,11 +123,9 @@ pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
         flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
         return pmd;
 }
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
 #ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
                           pmd_t *pmdp)
 {
@@ -145,11 +135,9 @@ void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
         /* tlb flush only to serialize against gup-fast */
         flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 }
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
 #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
                                 pgtable_t pgtable)
 {
@@ -162,11 +150,9 @@ void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
                 list_add(&pgtable->lru, &pmd_huge_pte(mm, pmdp)->lru);
         pmd_huge_pte(mm, pmdp) = pgtable;
 }
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
 #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 /* no "address" argument so destroys page coloring of some arch */
 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 {
@@ -185,11 +171,9 @@ pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
         }
         return pgtable;
 }
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
 #ifndef __HAVE_ARCH_PMDP_INVALIDATE
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
                      pmd_t *pmdp)
 {
@@ -197,11 +181,9 @@ void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
         set_pmd_at(vma->vm_mm, address, pmdp, pmd_mknotpresent(entry));
         flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 }
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
 #ifndef pmdp_collapse_flush
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
                           pmd_t *pmdp)
 {
@@ -217,5 +199,5 @@ pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
         flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
         return pmd;
 }
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */