[PATCH] Optimize D-cache alias handling on fork

Virtually index, physically tagged cache architectures can get away
without cache flushing when forking.  This patch adds a new cache
flushing function flush_cache_dup_mm(struct mm_struct *) which for the
moment I've implemented to do the same thing on all architectures
except on MIPS where it's a no-op.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/asm-sh/cpu-sh3/cacheflush.h b/include/asm-sh/cpu-sh3/cacheflush.h
index 03fde97..f70d8ef7 100644
--- a/include/asm-sh/cpu-sh3/cacheflush.h
+++ b/include/asm-sh/cpu-sh3/cacheflush.h
@@ -15,6 +15,7 @@
  *
  *  - flush_cache_all() flushes entire cache
  *  - flush_cache_mm(mm) flushes the specified mm context's cache lines
+ *  - flush_cache_dup mm(mm) handles cache flushing when forking
  *  - flush_cache_page(mm, vmaddr, pfn) flushes a single page
  *  - flush_cache_range(vma, start, end) flushes a range of pages
  *
@@ -39,6 +40,7 @@
 
 void flush_cache_all(void);
 void flush_cache_mm(struct mm_struct *mm);
+#define flush_cache_dup_mm(mm) flush_cache_mm(mm)
 void flush_cache_range(struct vm_area_struct *vma, unsigned long start,
                               unsigned long end);
 void flush_cache_page(struct vm_area_struct *vma, unsigned long addr, unsigned long pfn);
@@ -48,6 +50,7 @@
 #else
 #define flush_cache_all()			do { } while (0)
 #define flush_cache_mm(mm)			do { } while (0)
+#define flush_cache_dup_mm(mm)			do { } while (0)
 #define flush_cache_range(vma, start, end)	do { } while (0)
 #define flush_cache_page(vma, vmaddr, pfn)	do { } while (0)
 #define flush_dcache_page(page)			do { } while (0)