perf callchain: Move initial entry call into get_entries function

Moving initial entry call into get_entries function so all entries
processing is on one place. It will be useful for next change that adds
ordering logic.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Milian Wolff <milian.wolff@kdab.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1447772739-18471-2-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/unwind-libunwind.c

@@ -614,10 +614,22 @@ void unwind__finish_access(struct thread *thread)
 static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,
 		       void *arg, int max_stack)
 {
+	u64 val;
 	unw_addr_space_t addr_space;
 	unw_cursor_t c;
 	int ret;
 
+	ret = perf_reg_value(&val, &ui->sample->user_regs, PERF_REG_IP);
+	if (ret)
+		return ret;
+
+	ret = entry(val, ui->thread, cb, arg);
+	if (ret)
+		return -ENOMEM;
+
+	if (--max_stack == 0)
+		return 0;
+
 	addr_space = thread__priv(ui->thread);
 	if (addr_space == NULL)
 		return -1;
@@ -640,24 +652,17 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
 			struct thread *thread,
 			struct perf_sample *data, int max_stack)
 {
-	u64 ip;
 	struct unwind_info ui = {
 		.sample       = data,
 		.thread       = thread,
 		.machine      = thread->mg->machine,
 	};
-	int ret;
 
 	if (!data->user_regs.regs)
 		return -EINVAL;
 
-	ret = perf_reg_value(&ip, &data->user_regs, PERF_REG_IP);
-	if (ret)
-		return ret;
-
-	ret = entry(ip, thread, cb, arg);
-	if (ret)
-		return -ENOMEM;
+	if (max_stack <= 0)
+		return -EINVAL;
 
-	return --max_stack > 0 ? get_entries(&ui, cb, arg, max_stack) : 0;
+	return get_entries(&ui, cb, arg, max_stack);
 }