firmware: arm_sdei: Common block for failing path in sdei_event_create()

There are multiple calls of kfree(event) in the failing path of
sdei_event_create() to free the SDEI event. It means we need to
call it again when adding more code in the failing path. It's
prone to miss doing that and introduce memory leakage.

This introduces common block for failing path in sdei_event_create()
to resolve the issue. This shouldn't cause functional changes.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20200922130423.10173-3-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>

drivers/firmware/arm_sdei.c

@@ -190,33 +190,31 @@ static struct sdei_event *sdei_event_create(u32 event_num,
 	lockdep_assert_held(&sdei_events_lock);
 
 	event = kzalloc(sizeof(*event), GFP_KERNEL);
-	if (!event)
-		return ERR_PTR(-ENOMEM);
+	if (!event) {
+		err = -ENOMEM;
+		goto fail;
+	}
 
 	INIT_LIST_HEAD(&event->list);
 	event->event_num = event_num;
 
 	err = sdei_api_event_get_info(event_num, SDEI_EVENT_INFO_EV_PRIORITY,
 				      &result);
-	if (err) {
-		kfree(event);
-		return ERR_PTR(err);
-	}
+	if (err)
+		goto fail;
 	event->priority = result;
 
 	err = sdei_api_event_get_info(event_num, SDEI_EVENT_INFO_EV_TYPE,
 				      &result);
-	if (err) {
-		kfree(event);
-		return ERR_PTR(err);
-	}
+	if (err)
+		goto fail;
 	event->type = result;
 
 	if (event->type == SDEI_EVENT_TYPE_SHARED) {
 		reg = kzalloc(sizeof(*reg), GFP_KERNEL);
 		if (!reg) {
-			kfree(event);
-			return ERR_PTR(-ENOMEM);
+			err = -ENOMEM;
+			goto fail;
 		}
 
 		reg->event_num = event_num;
@@ -231,8 +229,8 @@ static struct sdei_event *sdei_event_create(u32 event_num,
 
 		regs = alloc_percpu(struct sdei_registered_event);
 		if (!regs) {
-			kfree(event);
-			return ERR_PTR(-ENOMEM);
+			err = -ENOMEM;
+			goto fail;
 		}
 
 		for_each_possible_cpu(cpu) {
@@ -252,6 +250,10 @@ static struct sdei_event *sdei_event_create(u32 event_num,
 	spin_unlock(&sdei_list_lock);
 
 	return event;
+
+fail:
+	kfree(event);
+	return ERR_PTR(err);
 }
 
 static void sdei_event_destroy_llocked(struct sdei_event *event)