KVM: arm64: vgic-its: Simplify MAPI error handling

If we care to move all the checks that do not involve any memory
allocation, we can simplify the MAPI error handling. Let's do that,
it cannot hurt.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

virt/kvm/arm/vgic/vgic-its.c

@@ -697,36 +697,34 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its,
 	struct its_device *device;
 	struct its_collection *collection, *new_coll = NULL;
 	int lpi_nr;
-	int ret;
 
 	device = find_its_device(its, device_id);
 	if (!device)
 		return E_ITS_MAPTI_UNMAPPED_DEVICE;
 
-	collection = find_collection(its, coll_id);
-	if (!collection) {
-		ret = vgic_its_alloc_collection(its, &collection, coll_id);
-		if (ret)
-			return ret;
-		new_coll = collection;
-	}
-
 	if (its_cmd_get_command(its_cmd) == GITS_CMD_MAPTI)
 		lpi_nr = its_cmd_get_physical_id(its_cmd);
 	else
 		lpi_nr = event_id;
 	if (lpi_nr < GIC_LPI_OFFSET ||
-	    lpi_nr >= max_lpis_propbaser(kvm->arch.vgic.propbaser)) {
-		ret = E_ITS_MAPTI_PHYSICALID_OOR;
-		goto err;
+	    lpi_nr >= max_lpis_propbaser(kvm->arch.vgic.propbaser))
+		return E_ITS_MAPTI_PHYSICALID_OOR;
+
+	collection = find_collection(its, coll_id);
+	if (!collection) {
+		int ret = vgic_its_alloc_collection(its, &collection, coll_id);
+		if (ret)
+			return ret;
+		new_coll = collection;
 	}
 
 	itte = find_itte(its, device_id, event_id);
 	if (!itte) {
 		itte = kzalloc(sizeof(struct its_itte), GFP_KERNEL);
 		if (!itte) {
-			ret = -ENOMEM;
-			goto err;
+			if (new_coll)
+				vgic_its_free_collection(its, coll_id);
+			return -ENOMEM;
 		}
 
 		itte->event_id	= event_id;
@@ -746,10 +744,6 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its,
 	update_lpi_config(kvm, itte->irq, NULL);
 
 	return 0;
-err:
-	if (new_coll)
-		vgic_its_free_collection(its, coll_id);
-	return ret;
 }
 
 /* Requires the its_lock to be held. */