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Date: Mon, 22 Apr 2024 15:09:31 +0200
From: Vincenzo Mezzela <vincenzo.mezzela@...il.com>
To: sudeep.holla@....com
Cc: gregkh@...uxfoundation.org,
javier.carrasco.cruz@...il.com,
julia.lawall@...ia.fr,
linux-kernel@...r.kernel.org,
rafael@...nel.org,
skhan@...uxfoundation.org,
vincenzo.mezzela@...il.com
Subject: [PATCH v2] drivers: 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.
Suggested-by: Julia Lawall <julia.lawall@...ia.fr>
Signed-off-by: Vincenzo Mezzela <vincenzo.mezzela@...il.com>
---
changes in v2:
- check loop exit condition within the loop
- add cleanup.h header
drivers/base/arch_topology.c | 150 +++++++++++++++++------------------
1 file changed, 73 insertions(+), 77 deletions(-)
diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index 024b78a0cfc1..c9c4af55953e 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -20,6 +20,7 @@
#include <linux/rcupdate.h>
#include <linux/sched.h>
#include <linux/units.h>
+#include <linux/cleanup.h>
#define CREATE_TRACE_POINTS
#include <trace/events/thermal_pressure.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;
- cpu_node = of_parse_phandle(node, "cpu", 0);
+ struct device_node *cpu_node __free(device_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;
}
@@ -538,28 +538,27 @@ 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 {
+ for(;;) {
snprintf(name, sizeof(name), "thread%d", i);
- t = of_get_child_by_name(core, name);
- if (t) {
- leaf = false;
- cpu = get_cpu_for_node(t);
- if (cpu >= 0) {
- cpu_topology[cpu].package_id = package_id;
- cpu_topology[cpu].cluster_id = cluster_id;
- cpu_topology[cpu].core_id = core_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);
+ struct device_node *t __free(device_node) =
+ of_get_child_by_name(core, name);
+ if (!t)
+ break;
+
+ leaf = false;
+ cpu = get_cpu_for_node(t);
+ if (cpu >= 0) {
+ cpu_topology[cpu].package_id = package_id;
+ cpu_topology[cpu].cluster_id = cluster_id;
+ cpu_topology[cpu].core_id = core_id;
+ cpu_topology[cpu].thread_id = i;
+ } else if (cpu != -ENODEV) {
+ pr_err("%pOF: Can't get CPU for thread\n", t);
+ return -EINVAL;
}
i++;
- } while (t);
+ }
cpu = get_cpu_for_node(core);
if (cpu >= 0) {
@@ -586,7 +585,6 @@ 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;
@@ -596,51 +594,51 @@ static int __init parse_cluster(struct device_node *cluster, int package_id,
* scheduler with a flat list of them.
*/
i = 0;
- do {
+ for(;;) {
snprintf(name, sizeof(name), "cluster%d", i);
- c = of_get_child_by_name(cluster, name);
- if (c) {
- leaf = false;
- 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;
- }
+ struct device_node *c __free(device_node) =
+ of_get_child_by_name(cluster, name);
+ if (!c)
+ break;
+
+ leaf = false;
+ ret = parse_cluster(c, package_id, i, depth + 1);
+ if (depth > 0)
+ pr_warn("Topology for clusters of clusters not yet supported\n");
+ if (ret != 0)
+ return ret;
i++;
- } while (c);
+ }
/* Now check for cores */
i = 0;
- do {
+ for(;;) {
snprintf(name, sizeof(name), "core%d", i);
- c = of_get_child_by_name(cluster, name);
- if (c) {
- has_cores = true;
-
- if (depth == 0) {
- pr_err("%pOF: cpu-map children should be clusters\n",
- c);
- of_node_put(c);
- return -EINVAL;
- }
+ struct device_node *c __free(device_node) =
+ of_get_child_by_name(cluster, name);
+ if (!c)
+ break;
- if (leaf) {
- ret = parse_core(c, package_id, cluster_id,
- core_id++);
- } else {
- pr_err("%pOF: Non-leaf cluster with core %s\n",
- cluster, name);
- ret = -EINVAL;
- }
+ has_cores = true;
- of_node_put(c);
- if (ret != 0)
- return ret;
+ if (depth == 0) {
+ pr_err("%pOF: cpu-map children should be clusters\n", c);
+ return -EINVAL;
+ }
+
+ if (leaf) {
+ ret = parse_core(c, package_id, cluster_id, core_id++);
+ } else {
+ pr_err("%pOF: Non-leaf cluster with core %s\n",
+ cluster, name);
+ ret = -EINVAL;
}
+
+ if (ret != 0)
+ return ret;
+
i++;
- } while (c);
+ }
if (leaf && !has_cores)
pr_warn("%pOF: empty cluster\n", cluster);
@@ -651,22 +649,23 @@ 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 {
+ for(;;) {
snprintf(name, sizeof(name), "socket%d", package_id);
- c = of_get_child_by_name(socket, name);
- if (c) {
- has_socket = true;
- ret = parse_cluster(c, package_id, -1, 0);
- of_node_put(c);
- if (ret != 0)
- return ret;
- }
+ 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);
+ if (ret != 0)
+ return ret;
+
package_id++;
- } while (c);
+ }
if (!has_socket)
ret = parse_cluster(socket, 0, -1, 0);
@@ -676,11 +675,11 @@ 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;
- cn = of_find_node_by_path("/cpus");
+ struct device_node *cn __free(device_node) =
+ of_find_node_by_path("/cpus");
if (!cn) {
pr_err("No CPU information found in DT\n");
return 0;
@@ -690,13 +689,14 @@ 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();
@@ -710,10 +710,6 @@ static int __init parse_dt_topology(void)
break;
}
-out_map:
- of_node_put(map);
-out:
- of_node_put(cn);
return ret;
}
#endif
--
2.34.1
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