11 files changed, 92 insertions, 46 deletions

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index dc8f99ee305f..7d7bcf990e99 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -27,13 +27,20 @@ do {				  					\
  * Largely same as above, but only sets the access flags (dirty,
  * accessed, and writable). Furthermore, we know it always gets set
  * to a "more permissive" setting, which allows most architectures
- * to optimize this.
+ * to optimize this. We return whether the PTE actually changed, which
+ * in turn instructs the caller to do things like update__mmu_cache.
+ * This used to be done in the caller, but sparc needs minor faults to
+ * force that call on sun4c so we changed this macro slightly
  */
 #define ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
-do {                                                                      \
-        set_pte_at((__vma)->vm_mm, (__address), __ptep, __entry);         \
-        flush_tlb_page(__vma, __address);                                 \
-} while (0)
+({                                                                        \
+        int __changed = !pte_same(*(__ptep), __entry);                    \
+        if (__changed) {                                                  \
+                set_pte_at((__vma)->vm_mm, (__address), __ptep, __entry); \
+                flush_tlb_page(__vma, __address);                         \
+        }                                                                 \
+        __changed;                                                        \
+})
 #endif
 
 #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
diff --git a/include/asm-i386/pgtable.h b/include/asm-i386/pgtable.h
index d62bdb029efa..628fa7747d0c 100644
--- a/include/asm-i386/pgtable.h
+++ b/include/asm-i386/pgtable.h
@@ -285,13 +285,15 @@ static inline pte_t native_local_ptep_get_and_clear(pte_t *ptep)
  */
 #define  __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
 #define ptep_set_access_flags(vma, address, ptep, entry, dirty)         \
-do {                                                                    \
-        if (dirty) {                                                    \
+({                                                                      \
+        int __changed = !pte_same(*(ptep), entry);                      \
+        if (__changed && dirty) {                                       \
                 (ptep)->pte_low = (entry).pte_low;                      \
                 pte_update_defer((vma)->vm_mm, (address), (ptep));      \
                 flush_tlb_page(vma, address);                           \
         }                                                               \
-} while (0)
+        __changed;                                                      \
+})
 
 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY
 #define ptep_test_and_clear_dirty(vma, addr, ptep) ({                   \
diff --git a/include/asm-ia64/pgtable.h b/include/asm-ia64/pgtable.h
index 670b706411b8..6580f31b3135 100644
--- a/include/asm-ia64/pgtable.h
+++ b/include/asm-ia64/pgtable.h
@@ -533,16 +533,23 @@ extern void lazy_mmu_prot_update (pte_t pte);
  * daccess_bit in ivt.S).
  */
 #ifdef CONFIG_SMP
-# define ptep_set_access_flags(__vma, __addr, __ptep, __entry, __safely_writable)       \
-do {                                                                                    \
-        if (__safely_writable) {                                                        \
-                set_pte(__ptep, __entry);                                               \
-                flush_tlb_page(__vma, __addr);                                          \
-        }                                                                               \
-} while (0)
+# define ptep_set_access_flags(__vma, __addr, __ptep, __entry, __safely_writable) \
+({                                                                      \
+        int __changed = !pte_same(*(__ptep), __entry);                  \
+        if (__changed && __safely_writable) {                           \
+                set_pte(__ptep, __entry);                               \
+                flush_tlb_page(__vma, __addr);                          \
+        }                                                               \
+        __changed;                                                      \
+})
 #else
-# define ptep_set_access_flags(__vma, __addr, __ptep, __entry, __safely_writable)       \
-        ptep_establish(__vma, __addr, __ptep, __entry)
+# define ptep_set_access_flags(__vma, __addr, __ptep, __entry, __safely_writable) \
+({                                                                      \
+        int __changed = !pte_same(*(__ptep), __entry);                  \
+        if (__changed)                                                  \
+                ptep_establish(__vma, __addr, __ptep, __entry);         \
+        __changed;                                                      \
+})
 #endif
 
 #  ifdef CONFIG_VIRTUAL_MEM_MAP
diff --git a/include/asm-powerpc/pgtable-ppc32.h b/include/asm-powerpc/pgtable-ppc32.h
index c863bdb2889c..7fb730c62f83 100644
--- a/include/asm-powerpc/pgtable-ppc32.h
+++ b/include/asm-powerpc/pgtable-ppc32.h
@@ -673,10 +673,14 @@ static inline void __ptep_set_access_flags(pte_t *ptep, pte_t entry, int dirty)
 }
 
 #define  ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
-        do {                                                               \
-                __ptep_set_access_flags(__ptep, __entry, __dirty);         \
-                flush_tlb_page_nohash(__vma, __address);                   \
-        } while(0)
+({                                                                         \
+        int __changed = !pte_same(*(__ptep), __entry);                     \
+        if (__changed) {                                                   \
+                __ptep_set_access_flags(__ptep, __entry, __dirty);         \
+                flush_tlb_page_nohash(__vma, __address);                   \
+        }                                                                  \
+        __changed;                                                         \
+})
 
 /*
  * Macro to mark a page protection value as "uncacheable".
diff --git a/include/asm-powerpc/pgtable-ppc64.h b/include/asm-powerpc/pgtable-ppc64.h
index 704c4e669fe0..3cfd98f44bfe 100644
--- a/include/asm-powerpc/pgtable-ppc64.h
+++ b/include/asm-powerpc/pgtable-ppc64.h
@@ -413,10 +413,14 @@ static inline void __ptep_set_access_flags(pte_t *ptep, pte_t entry, int dirty)
         :"cc");
 }
 #define  ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
-        do {                                                               \
-                __ptep_set_access_flags(__ptep, __entry, __dirty);         \
-                flush_tlb_page_nohash(__vma, __address);                   \
-        } while(0)
+({                                                                         \
+        int __changed = !pte_same(*(__ptep), __entry);                     \
+        if (__changed) {                                                   \
+                __ptep_set_access_flags(__ptep, __entry, __dirty);         \
+                flush_tlb_page_nohash(__vma, __address);                   \
+        }                                                                  \
+        __changed;                                                         \
+})
 
 /*
  * Macro to mark a page protection value as "uncacheable".
diff --git a/include/asm-ppc/pgtable.h b/include/asm-ppc/pgtable.h
index bed452d4a5f0..9d0ce9ff5840 100644
--- a/include/asm-ppc/pgtable.h
+++ b/include/asm-ppc/pgtable.h
@@ -694,10 +694,14 @@ static inline void __ptep_set_access_flags(pte_t *ptep, pte_t entry, int dirty)
 }
 
 #define  ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
-        do {                                                               \
-                __ptep_set_access_flags(__ptep, __entry, __dirty);         \
-                flush_tlb_page_nohash(__vma, __address);                   \
-        } while(0)
+({                                                                         \
+        int __changed = !pte_same(*(__ptep), __entry);                     \
+        if (__changed) {                                                   \
+                __ptep_set_access_flags(__ptep, __entry, __dirty);         \
+                flush_tlb_page_nohash(__vma, __address);                   \
+        }                                                                  \
+        __changed;                                                         \
+})
 
 /*
  * Macro to mark a page protection value as "uncacheable".
diff --git a/include/asm-s390/pgtable.h b/include/asm-s390/pgtable.h
index 8fe8d42e64c3..0a307bb2f353 100644
--- a/include/asm-s390/pgtable.h
+++ b/include/asm-s390/pgtable.h
@@ -744,7 +744,12 @@ ptep_establish(struct vm_area_struct *vma,
 }
 
 #define ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
-        ptep_establish(__vma, __address, __ptep, __entry)
+({                                                                        \
+        int __changed = !pte_same(*(__ptep), __entry);                    \
+        if (__changed)                                                    \
+                ptep_establish(__vma, __address, __ptep, __entry);        \
+        __changed;                                                        \
+})
 
 /*
  * Test and clear dirty bit in storage key.
diff --git a/include/asm-sparc/pgtable.h b/include/asm-sparc/pgtable.h
index 4f0a5ba0d6a0..59229aeba27b 100644
--- a/include/asm-sparc/pgtable.h
+++ b/include/asm-sparc/pgtable.h
@@ -446,6 +446,17 @@ extern int io_remap_pfn_range(struct vm_area_struct *vma,
 #define GET_IOSPACE(pfn)                (pfn >> (BITS_PER_LONG - 4))
 #define GET_PFN(pfn)                    (pfn & 0x0fffffffUL)
 
+#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
+#define ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
+({                                                                        \
+        int __changed = !pte_same(*(__ptep), __entry);                    \
+        if (__changed) {                                                  \
+                set_pte_at((__vma)->vm_mm, (__address), __ptep, __entry); \
+                flush_tlb_page(__vma, __address);                         \
+        }                                                                 \
+        (sparc_cpu_model == sun4c) || __changed;                          \
+})
+
 #include <asm-generic/pgtable.h>
 
 #endif /* !(__ASSEMBLY__) */
diff --git a/include/asm-x86_64/pgtable.h b/include/asm-x86_64/pgtable.h
index 08b9831f2e14..0a71e0b9a619 100644
--- a/include/asm-x86_64/pgtable.h
+++ b/include/asm-x86_64/pgtable.h
@@ -395,12 +395,14 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
  * bit at the same time. */
 #define  __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
 #define ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
-        do {                                                              \
-                if (__dirty) {                                            \
-                        set_pte(__ptep, __entry);                         \
-                        flush_tlb_page(__vma, __address);                 \
-                }                                                         \
-        } while (0)
+({                                                                        \
+        int __changed = !pte_same(*(__ptep), __entry);                    \
+        if (__changed && __dirty) {                                       \
+                set_pte(__ptep, __entry);                                 \
+                flush_tlb_page(__vma, __address);                         \
+        }                                                                 \
+        __changed;                                                        \
+})
 
 /* Encode and de-code a swap entry */
 #define __swp_type(x)                   (((x).val >> 1) & 0x3f)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index eb7180db3033..a45d1f0691ce 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -326,9 +326,10 @@ static void set_huge_ptep_writable(struct vm_area_struct *vma,
         pte_t entry;
 
         entry = pte_mkwrite(pte_mkdirty(*ptep));
-        ptep_set_access_flags(vma, address, ptep, entry, 1);
-        update_mmu_cache(vma, address, entry);
-        lazy_mmu_prot_update(entry);
+        if (ptep_set_access_flags(vma, address, ptep, entry, 1)) {
+                update_mmu_cache(vma, address, entry);
+                lazy_mmu_prot_update(entry);
+        }
 }
 
 
diff --git a/mm/memory.c b/mm/memory.c
index cb94488ab96d..f64cbf9baa36 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1691,9 +1691,10 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
                 flush_cache_page(vma, address, pte_pfn(orig_pte));
                 entry = pte_mkyoung(orig_pte);
                 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
-                ptep_set_access_flags(vma, address, page_table, entry, 1);
-                update_mmu_cache(vma, address, entry);
-                lazy_mmu_prot_update(entry);
+                if (ptep_set_access_flags(vma, address, page_table, entry,1)) {
+                        update_mmu_cache(vma, address, entry);
+                        lazy_mmu_prot_update(entry);
+                }
                 ret |= VM_FAULT_WRITE;
                 goto unlock;
         }
@@ -2525,10 +2526,9 @@ static inline int handle_pte_fault(struct mm_struct *mm,
                 pte_t *pte, pmd_t *pmd, int write_access)
 {
         pte_t entry;
-        pte_t old_entry;
         spinlock_t *ptl;
 
-        old_entry = entry = *pte;
+        entry = *pte;
         if (!pte_present(entry)) {
                 if (pte_none(entry)) {
                         if (vma->vm_ops) {
@@ -2561,8 +2561,7 @@ static inline int handle_pte_fault(struct mm_struct *mm,
                 entry = pte_mkdirty(entry);
         }
         entry = pte_mkyoung(entry);
-        if (!pte_same(old_entry, entry)) {
-                ptep_set_access_flags(vma, address, pte, entry, write_access);
+        if (ptep_set_access_flags(vma, address, pte, entry, write_access)) {
                 update_mmu_cache(vma, address, entry);
                 lazy_mmu_prot_update(entry);
         } else {