linux-kernel - [PATCH 2/6] platform/x86: firmware_attributes

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250104-firmware-attributes-simplify-v1-2-949f9709e405@weissschuh.net>
Date: Sat, 04 Jan 2025 00:05:10 +0100
From: Thomas Weißschuh <linux@...ssschuh.net>
To: Hans de Goede <hdegoede@...hat.com>, 
 Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>, 
 Mark Pearson <markpearson@...ovo.com>, Jorge Lopez <jorge.lopez2@...com>, 
 Prasanth Ksr <prasanth.ksr@...l.com>
Cc: Joshua Grisham <josh@...huagrisham.com>, 
 platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Dell.Client.Kernel@...l.com, 
 Thomas Weißschuh <linux@...ssschuh.net>
Subject: [PATCH 2/6] platform/x86: firmware_attributes_class: Simplify API

The module core already guarantees that a module can only be unloaded
after all other modules using its symbols have been unloaded.
As it's already the responsibility of the drivers using
firmware_attributes_class to clean up their devices before unloading,
the lifetime of the firmware_attributes_class can be bound to the
lifetime of the module.
This enables the direct usage of firmware_attributes_class from the
drivers, without having to go through the lifecycle functions,
leading to simplifications for both the subsystem and its users.

Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
---
 drivers/platform/x86/firmware_attributes_class.c | 40 +++++++++---------------
 drivers/platform/x86/firmware_attributes_class.h |  1 +
 2 files changed, 15 insertions(+), 26 deletions(-)

diff --git a/drivers/platform/x86/firmware_attributes_class.c b/drivers/platform/x86/firmware_attributes_class.c
index cbc56e5db59283ba99ac0b915ac5fb2432afbdc9..87672c49e86ae3ef5b99aa99be532c1d84805adc 100644
--- a/drivers/platform/x86/firmware_attributes_class.c
+++ b/drivers/platform/x86/firmware_attributes_class.c
@@ -2,47 +2,35 @@
 
 /* Firmware attributes class helper module */
 
-#include <linux/mutex.h>
 #include <linux/module.h>
 #include "firmware_attributes_class.h"
 
-static DEFINE_MUTEX(fw_attr_lock);
-static int fw_attr_inuse;
-
-static const struct class firmware_attributes_class = {
+const struct class firmware_attributes_class = {
 	.name = "firmware-attributes",
 };
+EXPORT_SYMBOL_GPL(firmware_attributes_class);
+
+static __init int fw_attributes_class_init(void)
+{
+	return class_register(&firmware_attributes_class);
+}
+module_init(fw_attributes_class_init);
+
+static __exit void fw_attributes_class_exit(void)
+{
+	class_unregister(&firmware_attributes_class);
+}
+module_exit(fw_attributes_class_exit);
 
 int fw_attributes_class_get(const struct class **fw_attr_class)
 {
-	int err;
-
-	mutex_lock(&fw_attr_lock);
-	if (!fw_attr_inuse) { /*first time class is being used*/
-		err = class_register(&firmware_attributes_class);
-		if (err) {
-			mutex_unlock(&fw_attr_lock);
-			return err;
-		}
-	}
-	fw_attr_inuse++;
 	*fw_attr_class = &firmware_attributes_class;
-	mutex_unlock(&fw_attr_lock);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(fw_attributes_class_get);
 
 int fw_attributes_class_put(void)
 {
-	mutex_lock(&fw_attr_lock);
-	if (!fw_attr_inuse) {
-		mutex_unlock(&fw_attr_lock);
-		return -EINVAL;
-	}
-	fw_attr_inuse--;
-	if (!fw_attr_inuse) /* No more consumers */
-		class_unregister(&firmware_attributes_class);
-	mutex_unlock(&fw_attr_lock);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(fw_attributes_class_put);
diff --git a/drivers/platform/x86/firmware_attributes_class.h b/drivers/platform/x86/firmware_attributes_class.h
index 8e0f47cfdf92eb4dc8722b7d8371916af0d84efa..ef6c3764a83497ad7e75b0102154c92ce476e5ae 100644
--- a/drivers/platform/x86/firmware_attributes_class.h
+++ b/drivers/platform/x86/firmware_attributes_class.h
@@ -7,6 +7,7 @@
 
 #include <linux/device/class.h>
 
+extern const struct class firmware_attributes_class;
 int fw_attributes_class_get(const struct class **fw_attr_class);
 int fw_attributes_class_put(void);
 

-- 
2.47.1