thermal: netlink: Add genetlink bind/unbind notifications
authorStanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Fri, 23 Feb 2024 15:59:40 +0000 (16:59 +0100)
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>
Wed, 27 Mar 2024 13:50:26 +0000 (14:50 +0100)
Introduce a new feature to the thermal netlink framework, enabling the
registration of sub drivers to receive events via a notifier mechanism.
Specifically, implement genetlink family bind and unbind callbacks to send
BIND and UNBIND events.

The primary purpose of this enhancement is to facilitate the tracking of
user-space consumers by the Intel HFI driver. By leveraging these
notifications, the driver can determine when consumers are present
or absent.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
drivers/thermal/thermal_netlink.c
drivers/thermal/thermal_netlink.h

index 76a231a29654512fd7eba589b827182daa0d63a9..d407130563e5bc37f9038be3173fef1c36e91927 100644 (file)
@@ -7,17 +7,13 @@
  * Generic netlink for thermal management framework
  */
 #include <linux/module.h>
+#include <linux/notifier.h>
 #include <linux/kernel.h>
 #include <net/genetlink.h>
 #include <uapi/linux/thermal.h>
 
 #include "thermal_core.h"
 
-enum thermal_genl_multicast_groups {
-       THERMAL_GENL_SAMPLING_GROUP = 0,
-       THERMAL_GENL_EVENT_GROUP = 1,
-};
-
 static const struct genl_multicast_group thermal_genl_mcgrps[] = {
        [THERMAL_GENL_SAMPLING_GROUP] = { .name = THERMAL_GENL_SAMPLING_GROUP_NAME, },
        [THERMAL_GENL_EVENT_GROUP]  = { .name = THERMAL_GENL_EVENT_GROUP_NAME,  },
@@ -75,6 +71,7 @@ struct param {
 typedef int (*cb_t)(struct param *);
 
 static struct genl_family thermal_gnl_family;
+static BLOCKING_NOTIFIER_HEAD(thermal_genl_chain);
 
 static int thermal_group_has_listeners(enum thermal_genl_multicast_groups group)
 {
@@ -645,6 +642,27 @@ out_free_msg:
        return ret;
 }
 
+static int thermal_genl_bind(int mcgrp)
+{
+       struct thermal_genl_notify n = { .mcgrp = mcgrp };
+
+       if (WARN_ON_ONCE(mcgrp > THERMAL_GENL_MAX_GROUP))
+               return -EINVAL;
+
+       blocking_notifier_call_chain(&thermal_genl_chain, THERMAL_NOTIFY_BIND, &n);
+       return 0;
+}
+
+static void thermal_genl_unbind(int mcgrp)
+{
+       struct thermal_genl_notify n = { .mcgrp = mcgrp };
+
+       if (WARN_ON_ONCE(mcgrp > THERMAL_GENL_MAX_GROUP))
+               return;
+
+       blocking_notifier_call_chain(&thermal_genl_chain, THERMAL_NOTIFY_UNBIND, &n);
+}
+
 static const struct genl_small_ops thermal_genl_ops[] = {
        {
                .cmd = THERMAL_GENL_CMD_TZ_GET_ID,
@@ -679,6 +697,8 @@ static struct genl_family thermal_gnl_family __ro_after_init = {
        .version        = THERMAL_GENL_VERSION,
        .maxattr        = THERMAL_GENL_ATTR_MAX,
        .policy         = thermal_genl_policy,
+       .bind           = thermal_genl_bind,
+       .unbind         = thermal_genl_unbind,
        .small_ops      = thermal_genl_ops,
        .n_small_ops    = ARRAY_SIZE(thermal_genl_ops),
        .resv_start_op  = THERMAL_GENL_CMD_CDEV_GET + 1,
@@ -686,6 +706,16 @@ static struct genl_family thermal_gnl_family __ro_after_init = {
        .n_mcgrps       = ARRAY_SIZE(thermal_genl_mcgrps),
 };
 
+int thermal_genl_register_notifier(struct notifier_block *nb)
+{
+       return blocking_notifier_chain_register(&thermal_genl_chain, nb);
+}
+
+int thermal_genl_unregister_notifier(struct notifier_block *nb)
+{
+       return blocking_notifier_chain_unregister(&thermal_genl_chain, nb);
+}
+
 int __init thermal_netlink_init(void)
 {
        return genl_register_family(&thermal_gnl_family);
index 93a927e144d55fc51ec68c14d55bf495def0a6fb..e01221e8816b424517adc00ad627a1b26ce76ae6 100644 (file)
@@ -10,6 +10,19 @@ struct thermal_genl_cpu_caps {
        int efficiency;
 };
 
+enum thermal_genl_multicast_groups {
+       THERMAL_GENL_SAMPLING_GROUP = 0,
+       THERMAL_GENL_EVENT_GROUP = 1,
+       THERMAL_GENL_MAX_GROUP = THERMAL_GENL_EVENT_GROUP,
+};
+
+#define THERMAL_NOTIFY_BIND    0
+#define THERMAL_NOTIFY_UNBIND  1
+
+struct thermal_genl_notify {
+       int mcgrp;
+};
+
 struct thermal_zone_device;
 struct thermal_trip;
 struct thermal_cooling_device;
@@ -18,6 +31,9 @@ struct thermal_cooling_device;
 #ifdef CONFIG_THERMAL_NETLINK
 int __init thermal_netlink_init(void);
 void __init thermal_netlink_exit(void);
+int thermal_genl_register_notifier(struct notifier_block *nb);
+int thermal_genl_unregister_notifier(struct notifier_block *nb);
+
 int thermal_notify_tz_create(const struct thermal_zone_device *tz);
 int thermal_notify_tz_delete(const struct thermal_zone_device *tz);
 int thermal_notify_tz_enable(const struct thermal_zone_device *tz);
@@ -48,6 +64,16 @@ static inline int thermal_notify_tz_create(const struct thermal_zone_device *tz)
        return 0;
 }
 
+static inline int thermal_genl_register_notifier(struct notifier_block *nb)
+{
+       return 0;
+}
+
+static inline int thermal_genl_unregister_notifier(struct notifier_block *nb)
+{
+       return 0;
+}
+
 static inline int thermal_notify_tz_delete(const struct thermal_zone_device *tz)
 {
        return 0;