drivers: arch_topology: use __free attribute instead of of_node_put()

Introduce the __free attribute for scope-based resource management.
Resources allocated with __free are automatically released at the end of
the scope. This enhancement aims to mitigate memory management issues
associated with forgetting to release resources by utilizing __free
instead of of_node_put().

The declaration of the device_node used within the do-while loops is
moved directly within the loop so that the resource is automatically
freed at the end of each iteration.

Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Suggested-by: Julia Lawall <julia.lawall@inria.fr>
Signed-off-by: Vincenzo Mezzela <vincenzo.mezzela@gmail.com>
Link: https://lore.kernel.org/r/20240607163350.392971-3-vincenzo.mezzela@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index 583f11bd4d2e75f9d77a0ed4fb9249691534632a..75fcb75d551557efac69717b43046bf271a4dec4 100644 (file)
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -8,6 +8,7 @@
 
 #include <linux/acpi.h>
 #include <linux/cacheinfo.h>
+#include <linux/cleanup.h>
 #include <linux/cpu.h>
 #include <linux/cpufreq.h>
 #include <linux/device.h>
@@ -513,10 +514,10 @@ core_initcall(free_raw_capacity);
  */
 static int __init get_cpu_for_node(struct device_node *node)
 {
-       struct device_node *cpu_node;
        int cpu;
+       struct device_node *cpu_node __free(device_node) =
+               of_parse_phandle(node, "cpu", 0);
 
-       cpu_node = of_parse_phandle(node, "cpu", 0);
        if (!cpu_node)
                return -1;
 
@@ -527,7 +528,6 @@ static int __init get_cpu_for_node(struct device_node *node)
                pr_info("CPU node for %pOF exist but the possible cpu range is :%*pbl\n",
                        cpu_node, cpumask_pr_args(cpu_possible_mask));
 
-       of_node_put(cpu_node);
        return cpu;
 }
 
@@ -538,11 +538,12 @@ static int __init parse_core(struct device_node *core, int package_id,
        bool leaf = true;
        int i = 0;
        int cpu;
-       struct device_node *t;
 
        do {
                snprintf(name, sizeof(name), "thread%d", i);
-               t = of_get_child_by_name(core, name);
+               struct device_node *t __free(device_node) =
+                       of_get_child_by_name(core, name);
+
                if (!t)
                        break;
 
@@ -555,10 +556,8 @@ static int __init parse_core(struct device_node *core, int package_id,
                        cpu_topology[cpu].thread_id = i;
                } else if (cpu != -ENODEV) {
                        pr_err("%pOF: Can't get CPU for thread\n", t);
-                       of_node_put(t);
                        return -EINVAL;
                }
-               of_node_put(t);
                i++;
        } while (1);
 
@@ -587,7 +586,6 @@ static int __init parse_cluster(struct device_node *cluster, int package_id,
        char name[20];
        bool leaf = true;
        bool has_cores = false;
-       struct device_node *c;
        int core_id = 0;
        int i, ret;
 
@@ -599,7 +597,9 @@ static int __init parse_cluster(struct device_node *cluster, int package_id,
        i = 0;
        do {
                snprintf(name, sizeof(name), "cluster%d", i);
-               c = of_get_child_by_name(cluster, name);
+               struct device_node *c __free(device_node) =
+                       of_get_child_by_name(cluster, name);
+
                if (!c)
                        break;
 
@@ -607,7 +607,6 @@ static int __init parse_cluster(struct device_node *cluster, int package_id,
                ret = parse_cluster(c, package_id, i, depth + 1);
                if (depth > 0)
                        pr_warn("Topology for clusters of clusters not yet supported\n");
-               of_node_put(c);
                if (ret != 0)
                        return ret;
                i++;
@@ -617,7 +616,9 @@ static int __init parse_cluster(struct device_node *cluster, int package_id,
        i = 0;
        do {
                snprintf(name, sizeof(name), "core%d", i);
-               c = of_get_child_by_name(cluster, name);
+               struct device_node *c __free(device_node) =
+                       of_get_child_by_name(cluster, name);
+
                if (!c)
                        break;
 
@@ -625,21 +626,19 @@ static int __init parse_cluster(struct device_node *cluster, int package_id,
 
                if (depth == 0) {
                        pr_err("%pOF: cpu-map children should be clusters\n", c);
-                       of_node_put(c);
                        return -EINVAL;
                }
 
                if (leaf) {
                        ret = parse_core(c, package_id, cluster_id, core_id++);
+                       if (ret != 0)
+                               return ret;
                } else {
                        pr_err("%pOF: Non-leaf cluster with core %s\n",
                               cluster, name);
-                       ret = -EINVAL;
+                       return -EINVAL;
                }
 
-               of_node_put(c);
-               if (ret != 0)
-                       return ret;
                i++;
        } while (1);
 
@@ -652,19 +651,19 @@ static int __init parse_cluster(struct device_node *cluster, int package_id,
 static int __init parse_socket(struct device_node *socket)
 {
        char name[20];
-       struct device_node *c;
        bool has_socket = false;
        int package_id = 0, ret;
 
        do {
                snprintf(name, sizeof(name), "socket%d", package_id);
-               c = of_get_child_by_name(socket, name);
+               struct device_node *c __free(device_node) =
+                       of_get_child_by_name(socket, name);
+
                if (!c)
                        break;
 
                has_socket = true;
                ret = parse_cluster(c, package_id, -1, 0);
-               of_node_put(c);
                if (ret != 0)
                        return ret;
 
@@ -679,11 +678,11 @@ static int __init parse_socket(struct device_node *socket)
 
 static int __init parse_dt_topology(void)
 {
-       struct device_node *cn, *map;
        int ret = 0;
        int cpu;
+       struct device_node *cn __free(device_node) =
+               of_find_node_by_path("/cpus");
 
-       cn = of_find_node_by_path("/cpus");
        if (!cn) {
                pr_err("No CPU information found in DT\n");
                return 0;
@@ -693,13 +692,15 @@ static int __init parse_dt_topology(void)
         * When topology is provided cpu-map is essentially a root
         * cluster with restricted subnodes.
         */
-       map = of_get_child_by_name(cn, "cpu-map");
+       struct device_node *map __free(device_node) =
+               of_get_child_by_name(cn, "cpu-map");
+
        if (!map)
-               goto out;
+               return ret;
 
        ret = parse_socket(map);
        if (ret != 0)
-               goto out_map;
+               return ret;
 
        topology_normalize_cpu_scale();
 
@@ -709,14 +710,9 @@ static int __init parse_dt_topology(void)
         */
        for_each_possible_cpu(cpu)
                if (cpu_topology[cpu].package_id < 0) {
-                       ret = -EINVAL;
-                       break;
+                       return -EINVAL;
                }
 
-out_map:
-       of_node_put(map);
-out:
-       of_node_put(cn);
        return ret;
 }
 #endif