dma-mapping: prevent dma dependent code from linking on !HAS_DMA archs

[powerpc.git] / include / asm-generic / pgtable.h

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index dc8f99e..7d7bcf9 100644 (file)
--- 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