ftrace: Remove redundant swap function

To cover the common case of sorting an array of pointers, Daniel
Wagner recently modified the library sort() to use a specific swap
function for size==8, in addition to the size==4 case which was
already handled. Since sizeof(long) is either 4 or 8,
ftrace_swap_ips() is redundant and we can just let sort() pick an
appropriate and fast swap callback.

Link: http://lkml.kernel.org/r/1441834023-13130-1-git-send-email-linux@rasmusvillemoes.dk

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/ftrace.c

@@ -4788,17 +4788,6 @@ static int ftrace_cmp_ips(const void *a, const void *b)
 	return 0;
 }
 
-static void ftrace_swap_ips(void *a, void *b, int size)
-{
-	unsigned long *ipa = a;
-	unsigned long *ipb = b;
-	unsigned long t;
-
-	t = *ipa;
-	*ipa = *ipb;
-	*ipb = t;
-}
-
 static int ftrace_process_locs(struct module *mod,
 			       unsigned long *start,
 			       unsigned long *end)
@@ -4818,7 +4807,7 @@ static int ftrace_process_locs(struct module *mod,
 		return 0;
 
 	sort(start, count, sizeof(*start),
-	     ftrace_cmp_ips, ftrace_swap_ips);
+	     ftrace_cmp_ips, NULL);
 
 	start_pg = ftrace_allocate_pages(count);
 	if (!start_pg)