[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>

kernel/fork.c

diff --git a/kernel/fork.c b/kernel/fork.c
index d16c566..fc723e5 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -203,7 +203,7 @@
 	struct mempolicy *pol;
 
 	down_write(&oldmm->mmap_sem);
-	flush_cache_mm(oldmm);
+	flush_cache_dup_mm(oldmm);
 	/*
 	 * Not linked in yet - no deadlock potential:
 	 */