perf/x86/intel/rapl: Add proper error handling

Like uncore the rapl driver lacks error handling. It leaks memory and leaves
the hotplug notifier registered.

Add the proper error checks, cleanup the memory and register the hotplug
notifier only on success.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Harish Chegondi <harish.chegondi@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20160222221012.231222076@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/events/intel/rapl.c

@@ -686,6 +686,14 @@ static int rapl_check_hw_unit(void)
 	return 0;
 }
 
+static void __init cleanup_rapl_pmus(void)
+{
+	int cpu;
+
+	for_each_online_cpu(cpu)
+		kfree(per_cpu(rapl_pmu, cpu));
+}
+
 static const struct x86_cpu_id rapl_cpu_match[] = {
 	[0] = { .vendor = X86_VENDOR_INTEL, .family = 6 },
 	[1] = {},
@@ -702,7 +710,7 @@ static int __init rapl_pmu_init(void)
 	 * check for Intel processor family 6
 	 */
 	if (!x86_match_cpu(rapl_cpu_match))
-		return 0;
+		return -ENODEV;
 
 	/* check supported CPU */
 	switch (boot_cpu_data.x86_model) {
@@ -734,8 +742,9 @@ static int __init rapl_pmu_init(void)
 		break;
 	default:
 		/* unsupported */
-		return 0;
+		return -ENODEV;
 	}
+
 	ret = rapl_check_hw_unit();
 	if (ret)
 		return ret;
@@ -743,6 +752,7 @@ static int __init rapl_pmu_init(void)
 	/* run cpu model quirks */
 	for (quirk = rapl_quirks; quirk; quirk = quirk->next)
 		quirk->func();
+
 	cpu_notifier_register_begin();
 
 	for_each_online_cpu(cpu) {
@@ -752,15 +762,14 @@ static int __init rapl_pmu_init(void)
 		rapl_cpu_init(cpu);
 	}
 
-	__perf_cpu_notifier(rapl_cpu_notifier);
-
 	ret = perf_pmu_register(&rapl_pmu_class, "power", -1);
 	if (WARN_ON(ret)) {
 		pr_info("RAPL PMU detected, registration failed (%d), RAPL PMU disabled\n", ret);
-		cpu_notifier_register_done();
-		return -1;
+		goto out;
 	}
 
+	__perf_cpu_notifier(rapl_cpu_notifier);
+
 	pmu = __this_cpu_read(rapl_pmu);
 
 	pr_info("RAPL PMU detected,"
@@ -775,9 +784,13 @@ static int __init rapl_pmu_init(void)
 				rapl_domain_names[i], rapl_hw_unit[i]);
 		}
 	}
-out:
-	cpu_notifier_register_done();
 
+	cpu_notifier_register_done();
 	return 0;
+
+out:
+	cleanup_rapl_pmus();
+	cpu_notifier_register_done();
+	return ret;
 }
 device_initcall(rapl_pmu_init);