perf data: Correct -h output

There is currently only 1 'perf data' command, but supporting extra
commands was breaking the help output. Simplify for now so that the help
output is correct.

Before:
$ perf data -h

Usage: perf data [<common options>] <command> [<options>]

$ perf data
Usage:
perf data [<common options>] <command> [<options>]

Available commands:
convert - converts data file between formats

After:
$ perf data

Usage: perf data convert [<options>]

-f, --force don't complain, do it
-i, --input <file> input file name
-v, --verbose be more verbose
--all Convert all events
--to-ctf ... Convert to CTF format
--to-json ... Convert to JSON format
--tod Convert time to wall clock time

$ perf data -h

Usage: perf data convert [<options>]

-f, --force don't complain, do it
-i, --input <file> input file name
-v, --verbose be more verbose
--all Convert all events
--to-ctf ... Convert to CTF format
--to-json ... Convert to JSON format
--tod Convert time to wall clock time

Signed-off-by: Joshua Martinez <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Ian Rogers <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Stephane Eranian <[e-mail]>
Link: http://lore.kernel.org/lkml/[e-mail]
Signed-off-by: Ian Rogers <[e-mail]>
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/builtin-data.c

···
 #define for_each_cmd(cmd) \
 	for (cmd = data_cmds; cmd && cmd->name; cmd++)
 
-static const struct option data_options[] = {
-	OPT_END()
-};
-
 static const char * const data_subcommands[] = { "convert", NULL };
 
 static const char *data_usage[] = {
-	"perf data [<common options>] <command> [<options>]",
-	NULL
-};
-
-static void print_usage(void)
-{
-	struct data_cmd *cmd;
-
-	printf("Usage:\n");
-	printf("\t%s\n\n", data_usage[0]);
-	printf("\tAvailable commands:\n");
-
-	for_each_cmd(cmd) {
-		printf("\t %s\t- %s\n", cmd->name, cmd->summary);
-	}
-
-	printf("\n");
-}
-
-static const char * const data_convert_usage[] = {
 	"perf data convert [<options>]",
 	NULL
 };
 
-static int cmd_data_convert(int argc, const char **argv)
-{
-	const char *to_json = NULL;
-	const char *to_ctf = NULL;
-	struct perf_data_convert_opts opts = {
-		.force = false,
-		.all = false,
-	};
-	const struct option options[] = {
+const char *to_json;
+const char *to_ctf;
+struct perf_data_convert_opts opts = {
+	.force = false,
+	.all = false,
+};
+
+const struct option data_options[] = {
 		OPT_INCR('v', "verbose", &verbose, "be more verbose"),
 		OPT_STRING('i', "input", &input_name, "file", "input file name"),
 		OPT_STRING(0, "to-json", &to_json, NULL, "Convert to JSON format"),
···
 		OPT_END()
 	};
 
-	argc = parse_options(argc, argv, options,
-			     data_convert_usage, 0);
+static int cmd_data_convert(int argc, const char **argv)
+{
+
+	argc = parse_options(argc, argv, data_options,
+			     data_usage, 0);
 	if (argc) {
-		usage_with_options(data_convert_usage, options);
+		usage_with_options(data_usage, data_options);
 		return -1;
 	}
 
···
 	struct data_cmd *cmd;
 	const char *cmdstr;
 
-	/* No command specified. */
-	if (argc < 2)
-		goto usage;
-
 	argc = parse_options_subcommand(argc, argv, data_options, data_subcommands, data_usage,
 			     PARSE_OPT_STOP_AT_NON_OPTION);
-	if (argc < 1)
-		goto usage;
+
+	if (!argc) {
+		usage_with_options(data_usage, data_options);
+		return -1;
+	}
 
 	cmdstr = argv[0];
 
···
 	}
 
 	pr_err("Unknown command: %s\n", cmdstr);
-usage:
-	print_usage();
+	usage_with_options(data_usage, data_options);
 	return -1;
 }