x86/events/amd/iommu: Fix sysfs perf attribute groups

Introduce static amd_iommu_attr_groups to simplify the
sysfs attributes initialization code.

Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Jörg Rödel <joro@8bytes.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: iommu@lists.linux-foundation.org
Link: http://lkml.kernel.org/r/1487926102-13073-9-git-send-email-Suravee.Suthikulpanit@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/events/amd/iommu.c

@@ -43,14 +43,8 @@ struct perf_amd_iommu {
 	u8 max_counters;
 	u64 cntr_assign_mask;
 	raw_spinlock_t lock;
-	const struct attribute_group *attr_groups[4];
 };
 
-#define format_group	attr_groups[0]
-#define cpumask_group	attr_groups[1]
-#define events_group	attr_groups[2]
-#define null_group	attr_groups[3]
-
 /*---------------------------------------------
  * sysfs format attributes
  *---------------------------------------------*/
@@ -81,6 +75,10 @@ static struct attribute_group amd_iommu_format_group = {
 /*---------------------------------------------
  * sysfs events attributes
  *---------------------------------------------*/
+static struct attribute_group amd_iommu_events_group = {
+	.name = "events",
+};
+
 struct amd_iommu_event_desc {
 	struct kobj_attribute attr;
 	const char *event;
@@ -384,76 +382,60 @@ static void perf_iommu_del(struct perf_event *event, int flags)
 	perf_event_update_userpage(event);
 }
 
-static __init int _init_events_attrs(struct perf_amd_iommu *perf_iommu)
+static __init int _init_events_attrs(void)
 {
-	struct attribute **attrs;
-	struct attribute_group *attr_group;
 	int i = 0, j;
+	struct attribute **attrs;
 
 	while (amd_iommu_v2_event_descs[i].attr.attr.name)
 		i++;
 
-	attr_group = kzalloc(sizeof(struct attribute *)
-		* (i + 1) + sizeof(*attr_group), GFP_KERNEL);
-	if (!attr_group)
+	attrs = kzalloc(sizeof(struct attribute **) * (i + 1), GFP_KERNEL);
+	if (!attrs)
 		return -ENOMEM;
 
-	attrs = (struct attribute **)(attr_group + 1);
 	for (j = 0; j < i; j++)
 		attrs[j] = &amd_iommu_v2_event_descs[j].attr.attr;
 
-	attr_group->name = "events";
-	attr_group->attrs = attrs;
-	perf_iommu->events_group = attr_group;
-
+	amd_iommu_events_group.attrs = attrs;
 	return 0;
 }
 
 static __init void amd_iommu_pc_exit(void)
 {
-	if (__perf_iommu.events_group != NULL) {
-		kfree(__perf_iommu.events_group);
-		__perf_iommu.events_group = NULL;
-	}
+	kfree(amd_iommu_events_group.attrs);
 }
 
-static __init int _init_perf_amd_iommu(
-	struct perf_amd_iommu *perf_iommu, char *name)
+const struct attribute_group *amd_iommu_attr_groups[] = {
+	&amd_iommu_format_group,
+	&amd_iommu_cpumask_group,
+	&amd_iommu_events_group,
+	NULL,
+};
+
+static __init int
+_init_perf_amd_iommu(struct perf_amd_iommu *perf_iommu, char *name)
 {
 	int ret;
 
 	raw_spin_lock_init(&perf_iommu->lock);
 
-	perf_iommu->format_group = &amd_iommu_format_group;
-
 	/* Init cpumask attributes to only core 0 */
 	cpumask_set_cpu(0, &iommu_cpumask);
-	perf_iommu->cpumask_group = &amd_iommu_cpumask_group;
-
-	ret = _init_events_attrs(perf_iommu);
-	if (ret) {
-		pr_err("Error initializing AMD IOMMU perf events.\n");
-		return ret;
-	}
 
 	perf_iommu->max_banks    = amd_iommu_pc_get_max_banks(0);
 	perf_iommu->max_counters = amd_iommu_pc_get_max_counters(0);
 	if (!perf_iommu->max_banks || !perf_iommu->max_counters)
 		return -EINVAL;
 
-	perf_iommu->null_group = NULL;
-	perf_iommu->pmu.attr_groups = perf_iommu->attr_groups;
-
+	perf_iommu->pmu.attr_groups = amd_iommu_attr_groups;
 	ret = perf_pmu_register(&perf_iommu->pmu, name, -1);
-	if (ret) {
+	if (ret)
 		pr_err("Error initializing AMD IOMMU perf counters.\n");
-		amd_iommu_pc_exit();
-	} else {
+	else
 		pr_info("Detected AMD IOMMU (%d banks, %d counters/bank).\n",
 			amd_iommu_pc_get_max_banks(0),
 			amd_iommu_pc_get_max_counters(0));
-	}
-
 	return ret;
 }
 
@@ -467,24 +449,25 @@ static struct perf_amd_iommu __perf_iommu = {
 		.stop		= perf_iommu_stop,
 		.read		= perf_iommu_read,
 	},
-	.max_banks		= 0x00,
-	.max_counters		= 0x00,
-	.cntr_assign_mask	= 0ULL,
-	.format_group		= NULL,
-	.cpumask_group		= NULL,
-	.events_group		= NULL,
-	.null_group		= NULL,
 };
 
 static __init int amd_iommu_pc_init(void)
 {
+	int ret;
+
 	/* Make sure the IOMMU PC resource is available */
 	if (!amd_iommu_pc_supported())
 		return -ENODEV;
 
-	_init_perf_amd_iommu(&__perf_iommu, "amd_iommu");
+	ret = _init_events_attrs();
+	if (ret)
+		return ret;
 
-	return 0;
+	ret = _init_perf_amd_iommu(&__perf_iommu, "amd_iommu");
+	if (ret)
+		amd_iommu_pc_exit();
+
+	return ret;
 }
 
 device_initcall(amd_iommu_pc_init);