of: Use scope based of_node_put() cleanups

Use the relatively new scope based of_node_put() cleanup to simplify
function exit handling. Doing so reduces the chances of forgetting an
of_node_put() and simplifies error paths by avoiding the need for goto
statements.
Reviewed-by: Saravana Kannan <saravanak@google.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240409-dt-cleanup-free-v2-3-5b419a4af38d@kernel.orgSigned-off-by: Rob Herring <robh@kernel.org>

drivers/of/address.c

@@ -486,34 +486,30 @@ static int of_translate_one(struct device_node *parent, struct of_bus *bus,
  * device that had registered logical PIO mapping, and the return code is
  * relative to that node.
  */
-static u64 __of_translate_address(struct device_node *dev,
+static u64 __of_translate_address(struct device_node *node,
 				  struct device_node *(*get_parent)(const struct device_node *),
 				  const __be32 *in_addr, const char *rprop,
 				  struct device_node **host)
 {
-	struct device_node *parent = NULL;
+	struct device_node *dev __free(device_node) = of_node_get(node);
+	struct device_node *parent __free(device_node) = get_parent(dev);
 	struct of_bus *bus, *pbus;
 	__be32 addr[OF_MAX_ADDR_CELLS];
 	int na, ns, pna, pns;
-	u64 result = OF_BAD_ADDR;
 
 	pr_debug("** translation for device %pOF **\n", dev);
 
-	/* Increase refcount at current level */
-	of_node_get(dev);
-
 	*host = NULL;
-	/* Get parent & match bus type */
-	parent = get_parent(dev);
+
 	if (parent == NULL)
-		goto bail;
+		return OF_BAD_ADDR;
 	bus = of_match_bus(parent);
 
 	/* Count address cells & copy address locally */
 	bus->count_cells(dev, &na, &ns);
 	if (!OF_CHECK_COUNTS(na, ns)) {
 		pr_debug("Bad cell count for %pOF\n", dev);
-		goto bail;
+		return OF_BAD_ADDR;
 	}
 	memcpy(addr, in_addr, na * 4);
 
@@ -533,8 +529,7 @@ static u64 __of_translate_address(struct device_node *dev,
 		/* If root, we have finished */
 		if (parent == NULL) {
 			pr_debug("reached root node\n");
-			result = of_read_number(addr, na);
-			break;
+			return of_read_number(addr, na);
 		}
 
 		/*
@@ -543,11 +538,11 @@ static u64 __of_translate_address(struct device_node *dev,
 		 */
 		iorange = find_io_range_by_fwnode(&dev->fwnode);
 		if (iorange && (iorange->flags != LOGIC_PIO_CPU_MMIO)) {
-			result = of_read_number(addr + 1, na - 1);
+			u64 result = of_read_number(addr + 1, na - 1);
 			pr_debug("indirectIO matched(%pOF) 0x%llx\n",
 				 dev, result);
-			*host = of_node_get(dev);
-			break;
+			*host = no_free_ptr(dev);
+			return result;
 		}
 
 		/* Get new parent bus and counts */
@@ -555,7 +550,7 @@ static u64 __of_translate_address(struct device_node *dev,
 		pbus->count_cells(dev, &pna, &pns);
 		if (!OF_CHECK_COUNTS(pna, pns)) {
 			pr_err("Bad cell count for %pOF\n", dev);
-			break;
+			return OF_BAD_ADDR;
 		}
 
 		pr_debug("parent bus is %s (na=%d, ns=%d) on %pOF\n",
@@ -563,7 +558,7 @@ static u64 __of_translate_address(struct device_node *dev,
 
 		/* Apply bus translation */
 		if (of_translate_one(dev, bus, pbus, addr, na, ns, pna, rprop))
-			break;
+			return OF_BAD_ADDR;
 
 		/* Complete the move up one level */
 		na = pna;
@@ -572,11 +567,8 @@ static u64 __of_translate_address(struct device_node *dev,
 
 		of_dump_addr("one level translation:", addr, na);
 	}
- bail:
-	of_node_put(parent);
-	of_node_put(dev);
 
-	return result;
+	unreachable();
 }
 
 u64 of_translate_address(struct device_node *dev, const __be32 *in_addr)
@@ -654,19 +646,16 @@ EXPORT_SYMBOL(of_translate_dma_address);
 const __be32 *of_translate_dma_region(struct device_node *dev, const __be32 *prop,
 				      phys_addr_t *start, size_t *length)
 {
-	struct device_node *parent;
+	struct device_node *parent __free(device_node) = __of_get_dma_parent(dev);
 	u64 address, size;
 	int na, ns;
 
-	parent = __of_get_dma_parent(dev);
 	if (!parent)
 		return NULL;
 
 	na = of_bus_n_addr_cells(parent);
 	ns = of_bus_n_size_cells(parent);
 
-	of_node_put(parent);
-
 	address = of_translate_dma_address(dev, prop);
 	if (address == OF_BAD_ADDR)
 		return NULL;
@@ -688,21 +677,19 @@ const __be32 *__of_get_address(struct device_node *dev, int index, int bar_no,
 {
 	const __be32 *prop;
 	unsigned int psize;
-	struct device_node *parent;
+	struct device_node *parent __free(device_node) = of_get_parent(dev);
 	struct of_bus *bus;
 	int onesize, i, na, ns;
 
-	/* Get parent & match bus type */
-	parent = of_get_parent(dev);
 	if (parent == NULL)
 		return NULL;
+
+	/* match the parent's bus type */
 	bus = of_match_bus(parent);
-	if (strcmp(bus->name, "pci") && (bar_no >= 0)) {
-		of_node_put(parent);
+	if (strcmp(bus->name, "pci") && (bar_no >= 0))
 		return NULL;
-	}
+
 	bus->count_cells(dev, &na, &ns);
-	of_node_put(parent);
 	if (!OF_CHECK_ADDR_COUNT(na))
 		return NULL;
 
@@ -888,14 +875,13 @@ static u64 of_translate_ioport(struct device_node *dev, const __be32 *in_addr,
  */
 int of_dma_get_range(struct device_node *np, const struct bus_dma_region **map)
 {
-	struct device_node *node = of_node_get(np);
+	struct device_node *node __free(device_node) = of_node_get(np);
 	const __be32 *ranges = NULL;
 	bool found_dma_ranges = false;
 	struct of_range_parser parser;
 	struct of_range range;
 	struct bus_dma_region *r;
 	int len, num_ranges = 0;
-	int ret = 0;
 
 	while (node) {
 		ranges = of_get_property(node, "dma-ranges", &len);
@@ -905,10 +891,9 @@ int of_dma_get_range(struct device_node *np, const struct bus_dma_region **map)
 			break;
 
 		/* Once we find 'dma-ranges', then a missing one is an error */
-		if (found_dma_ranges && !ranges) {
-			ret = -ENODEV;
-			goto out;
-		}
+		if (found_dma_ranges && !ranges)
+			return -ENODEV;
+
 		found_dma_ranges = true;
 
 		node = of_get_next_dma_parent(node);
@@ -916,10 +901,8 @@ int of_dma_get_range(struct device_node *np, const struct bus_dma_region **map)
 
 	if (!node || !ranges) {
 		pr_debug("no dma-ranges found for node(%pOF)\n", np);
-		ret = -ENODEV;
-		goto out;
+		return -ENODEV;
 	}
-
 	of_dma_range_parser_init(&parser, node);
 	for_each_of_range(&parser, &range) {
 		if (range.cpu_addr == OF_BAD_ADDR) {
@@ -930,16 +913,12 @@ int of_dma_get_range(struct device_node *np, const struct bus_dma_region **map)
 		num_ranges++;
 	}
 
-	if (!num_ranges) {
-		ret = -EINVAL;
-		goto out;
-	}
+	if (!num_ranges)
+		return -EINVAL;
 
 	r = kcalloc(num_ranges + 1, sizeof(*r), GFP_KERNEL);
-	if (!r) {
-		ret = -ENOMEM;
-		goto out;
-	}
+	if (!r)
+		return -ENOMEM;
 
 	/*
 	 * Record all info in the generic DMA ranges array for struct device,
@@ -957,9 +936,7 @@ int of_dma_get_range(struct device_node *np, const struct bus_dma_region **map)
 		r->size = range.size;
 		r++;
 	}
-out:
-	of_node_put(node);
-	return ret;
+	return 0;
 }
 #endif /* CONFIG_HAS_DMA */
 
@@ -1016,24 +993,18 @@ phys_addr_t __init of_dma_get_max_cpu_address(struct device_node *np)
  */
 bool of_dma_is_coherent(struct device_node *np)
 {
-	struct device_node *node;
-	bool is_coherent = dma_default_coherent;
-
-	node = of_node_get(np);
+	struct device_node *node __free(device_node) = of_node_get(np);
 
 	while (node) {
-		if (of_property_read_bool(node, "dma-coherent")) {
-			is_coherent = true;
-			break;
-		}
-		if (of_property_read_bool(node, "dma-noncoherent")) {
-			is_coherent = false;
-			break;
-		}
+		if (of_property_read_bool(node, "dma-coherent"))
+			return true;
+
+		if (of_property_read_bool(node, "dma-noncoherent"))
+			return false;
+
 		node = of_get_next_dma_parent(node);
 	}
-	of_node_put(node);
-	return is_coherent;
+	return dma_default_coherent;
 }
 EXPORT_SYMBOL_GPL(of_dma_is_coherent);
 
@@ -1049,20 +1020,14 @@ EXPORT_SYMBOL_GPL(of_dma_is_coherent);
  */
 static bool of_mmio_is_nonposted(struct device_node *np)
 {
-	struct device_node *parent;
-	bool nonposted;
-
 	if (!IS_ENABLED(CONFIG_ARCH_APPLE))
 		return false;
 
-	parent = of_get_parent(np);
+	struct device_node *parent __free(device_node) = of_get_parent(np);
 	if (!parent)
 		return false;
 
-	nonposted = of_property_read_bool(parent, "nonposted-mmio");
-
-	of_node_put(parent);
-	return nonposted;
+	return of_property_read_bool(parent, "nonposted-mmio");
 }
 
 static int __of_address_to_resource(struct device_node *dev, int index, int bar_no,

drivers/of/property.c

@@ -40,15 +40,12 @@
  */
 bool of_graph_is_present(const struct device_node *node)
 {
-	struct device_node *ports, *port;
+	struct device_node *ports __free(device_node) = of_get_child_by_name(node, "ports");
 
-	ports = of_get_child_by_name(node, "ports");
 	if (ports)
 		node = ports;
 
-	port = of_get_child_by_name(node, "port");
-	of_node_put(ports);
-	of_node_put(port);
+	struct device_node *port __free(device_node) = of_get_child_by_name(node, "port");
 
 	return !!port;
 }
@@ -610,25 +607,22 @@ EXPORT_SYMBOL(of_graph_parse_endpoint);
  */
 struct device_node *of_graph_get_port_by_id(struct device_node *parent, u32 id)
 {
-	struct device_node *node, *port;
+	struct device_node *node __free(device_node) = of_get_child_by_name(parent, "ports");
 
-	node = of_get_child_by_name(parent, "ports");
 	if (node)
 		parent = node;
 
-	for_each_child_of_node(parent, port) {
+	for_each_child_of_node_scoped(parent, port) {
 		u32 port_id = 0;
 
 		if (!of_node_name_eq(port, "port"))
 			continue;
 		of_property_read_u32(port, "reg", &port_id);
 		if (id == port_id)
-			break;
+			return_ptr(port);
 	}
 
-	of_node_put(node);
-
-	return port;
+	return NULL;
 }
 EXPORT_SYMBOL(of_graph_get_port_by_id);
 
@@ -655,15 +649,13 @@ struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 	 * parent port node.
 	 */
 	if (!prev) {
-		struct device_node *node;
+		struct device_node *node __free(device_node) =
+			of_get_child_by_name(parent, "ports");
 
-		node = of_get_child_by_name(parent, "ports");
 		if (node)
 			parent = node;
 
 		port = of_get_child_by_name(parent, "port");
-		of_node_put(node);
-
 		if (!port) {
 			pr_debug("graph: no port node found in %pOF\n", parent);
 			return NULL;
@@ -1052,15 +1044,13 @@ static int of_fwnode_graph_parse_endpoint(const struct fwnode_handle *fwnode,
 					  struct fwnode_endpoint *endpoint)
 {
 	const struct device_node *node = to_of_node(fwnode);
-	struct device_node *port_node = of_get_parent(node);
+	struct device_node *port_node __free(device_node) = of_get_parent(node);
 
 	endpoint->local_fwnode = fwnode;
 
 	of_property_read_u32(port_node, "reg", &endpoint->port);
 	of_property_read_u32(node, "reg", &endpoint->id);
 
-	of_node_put(port_node);
-
 	return 0;
 }