perf target: Move the checking of which map function to call into function.

Check for cpu_map__dummy_new() or cpu_map__new() to be called in
perf_evlist__create_maps() is more complicated.

This patch moves the checking work into target.h, combining two
conditions and making perf_evlist__create_maps() more readable.

Signed-off-by: Dongsheng Yang <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: http://lkml.kernel.org/r/b8c[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/evlist.c

···
 	if (evlist->threads == NULL)
 		return -1;
 
-	if (target->default_per_cpu)
-		evlist->cpus = target->per_thread ?
-					cpu_map__dummy_new() :
-					cpu_map__new(target->cpu_list);
-	else if (target__has_task(target))
-		evlist->cpus = cpu_map__dummy_new();
-	else if (!target__has_cpu(target) && !target->uses_mmap)
+	if (target__uses_dummy_map(target))
 		evlist->cpus = cpu_map__dummy_new();
 	else
 		evlist->cpus = cpu_map__new(target->cpu_list);

tools/perf/util/target.h

···
 	return !target__has_task(target) && !target__has_cpu(target);
 }
 
+static inline bool target__uses_dummy_map(struct target *target)
+{
+	bool use_dummy = false;
+
+	if (target->default_per_cpu)
+		use_dummy = target->per_thread ? true : false;
+	else if (target__has_task(target) ||
+	         (!target__has_cpu(target) && !target->uses_mmap))
+		use_dummy = true;
+
+	return use_dummy;
+}
+
 #endif /* _PERF_TARGET_H */