perf: ftrace: Add set_tracing_options() to set all trace options

Now the __cmd_ftrace() becomes a bit long. This moves the trace option
setting code to a separate function set_tracing_options().
Suggested-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-18-changbin.du@gmail.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-ftrace.c

@@ -465,110 +465,118 @@ static int set_tracing_thresh(struct perf_ftrace *ftrace)
 	return 0;
 }
 
-static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
+static int set_tracing_options(struct perf_ftrace *ftrace)
 {
-	char *trace_file;
-	int trace_fd;
-	char buf[4096];
-	struct pollfd pollfd = {
-		.events = POLLIN,
-	};
-
-	if (!(perf_cap__capable(CAP_PERFMON) ||
-	      perf_cap__capable(CAP_SYS_ADMIN))) {
-		pr_err("ftrace only works for %s!\n",
-#ifdef HAVE_LIBCAP_SUPPORT
-		"users with the CAP_PERFMON or CAP_SYS_ADMIN capability"
-#else
-		"root"
-#endif
-		);
-		return -1;
-	}
-
-	signal(SIGINT, sig_handler);
-	signal(SIGUSR1, sig_handler);
-	signal(SIGCHLD, sig_handler);
-	signal(SIGPIPE, sig_handler);
-
-	if (ftrace->list_avail_functions)
-		return read_tracing_file_to_stdout("available_filter_functions");
-
-	if (reset_tracing_files(ftrace) < 0) {
-		pr_err("failed to reset ftrace\n");
-		goto out;
-	}
-
-	/* reset ftrace buffer */
-	if (write_tracing_file("trace", "0") < 0)
-		goto out;
-
-	if (argc && perf_evlist__prepare_workload(ftrace->evlist,
-				&ftrace->target, argv, false,
-				ftrace__workload_exec_failed_signal) < 0) {
-		goto out;
-	}
-
 	if (set_tracing_pid(ftrace) < 0) {
 		pr_err("failed to set ftrace pid\n");
-		goto out_reset;
+		return -1;
 	}
 
 	if (set_tracing_cpu(ftrace) < 0) {
 		pr_err("failed to set tracing cpumask\n");
-		goto out_reset;
+		return -1;
 	}
 
 	if (set_tracing_func_stack_trace(ftrace) < 0) {
 		pr_err("failed to set tracing option func_stack_trace\n");
-		goto out_reset;
+		return -1;
 	}
 
 	if (set_tracing_func_irqinfo(ftrace) < 0) {
 		pr_err("failed to set tracing option irq-info\n");
-		goto out_reset;
+		return -1;
 	}
 
 	if (set_tracing_filters(ftrace) < 0) {
 		pr_err("failed to set tracing filters\n");
-		goto out_reset;
+		return -1;
 	}
 
 	if (set_tracing_depth(ftrace) < 0) {
 		pr_err("failed to set graph depth\n");
-		goto out_reset;
+		return -1;
 	}
 
 	if (set_tracing_percpu_buffer_size(ftrace) < 0) {
 		pr_err("failed to set tracing per-cpu buffer size\n");
-		goto out_reset;
+		return -1;
 	}
 
 	if (set_tracing_trace_inherit(ftrace) < 0) {
 		pr_err("failed to set tracing option function-fork\n");
-		goto out_reset;
+		return -1;
 	}
 
 	if (set_tracing_sleep_time(ftrace) < 0) {
 		pr_err("failed to set tracing option sleep-time\n");
-		goto out_reset;
+		return -1;
 	}
 
 	if (set_tracing_funcgraph_irqs(ftrace) < 0) {
 		pr_err("failed to set tracing option funcgraph-irqs\n");
-		goto out_reset;
+		return -1;
 	}
 
 	if (set_tracing_funcgraph_verbose(ftrace) < 0) {
 		pr_err("failed to set tracing option funcgraph-proc/funcgraph-abstime\n");
-		goto out_reset;
+		return -1;
 	}
 
 	if (set_tracing_thresh(ftrace) < 0) {
 		pr_err("failed to set tracing thresh\n");
-		goto out_reset;
+		return -1;
+	}
+
+	return 0;
+}
+
+static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
+{
+	char *trace_file;
+	int trace_fd;
+	char buf[4096];
+	struct pollfd pollfd = {
+		.events = POLLIN,
+	};
+
+	if (!(perf_cap__capable(CAP_PERFMON) ||
+	      perf_cap__capable(CAP_SYS_ADMIN))) {
+		pr_err("ftrace only works for %s!\n",
+#ifdef HAVE_LIBCAP_SUPPORT
+		"users with the CAP_PERFMON or CAP_SYS_ADMIN capability"
+#else
+		"root"
+#endif
+		);
+		return -1;
 	}
 
+	signal(SIGINT, sig_handler);
+	signal(SIGUSR1, sig_handler);
+	signal(SIGCHLD, sig_handler);
+	signal(SIGPIPE, sig_handler);
+
+	if (ftrace->list_avail_functions)
+		return read_tracing_file_to_stdout("available_filter_functions");
+
+	if (reset_tracing_files(ftrace) < 0) {
+		pr_err("failed to reset ftrace\n");
+		goto out;
+	}
+
+	/* reset ftrace buffer */
+	if (write_tracing_file("trace", "0") < 0)
+		goto out;
+
+	if (argc && perf_evlist__prepare_workload(ftrace->evlist,
+				&ftrace->target, argv, false,
+				ftrace__workload_exec_failed_signal) < 0) {
+		goto out;
+	}
+
+	if (set_tracing_options(ftrace) < 0)
+		goto out_reset;
+
 	if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {
 		pr_err("failed to set current_tracer to %s\n", ftrace->tracer);
 		goto out_reset;