perf callchain: Move validate_callchain to callchain lib

Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index db628af..ac14861 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -17,6 +17,13 @@
 
 #include "callchain.h"
 
+bool ip_callchain__valid(struct ip_callchain *chain, event_t *event)
+{
+	unsigned int chain_size = event->header.size;
+	chain_size -= (unsigned long)&event->ip.__more_data - (unsigned long)event;
+	return chain->nr * sizeof(u64) <= chain_size;
+}
+
 #define chain_for_each_child(child, parent)	\
 	list_for_each_entry(child, &parent->children, brothers)