perf tools: Use sysctl__read_int instead of ad-hoc copies

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-pt2u7a3b50oddggecx7rwq2n@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/record.c

@@ -137,16 +137,7 @@ void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts)
 
 static int get_max_rate(unsigned int *rate)
 {
-	char path[PATH_MAX];
+	return sysctl__read_int("kernel/perf_event_max_sample_rate", (int *)rate);
-	const char *procfs = procfs__mountpoint();
-
-	if (!procfs)
-		return -1;
-
-	snprintf(path, PATH_MAX,
-		 "%s/sys/kernel/perf_event_max_sample_rate", procfs);
-
-	return filename__read_int(path, (int *) rate);
 }
 
 static int record_opts__config_freq(struct record_opts *opts)

tools/perf/util/util.c

@@ -506,16 +506,9 @@ const char *get_filename_for_perf_kvm(void)
 
 int perf_event_paranoid(void)
 {
-	char path[PATH_MAX];
-	const char *procfs = procfs__mountpoint();
 	int value;
 
-	if (!procfs)
+	if (sysctl__read_int("kernel/perf_event_paranoid", &value))
-		return INT_MAX;
-
-	scnprintf(path, PATH_MAX, "%s/sys/kernel/perf_event_paranoid", procfs);
-
-	if (filename__read_int(path, &value))
 		return INT_MAX;
 
 	return value;