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From: "Ricardo B. Marliere" <ricardo@marliere.net>
Date: Tue, 05 Mar 2024 10:37:50 -0300
Subject: [PATCH 1/2] mips: mt: make mt_class constant
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Message-Id: <20240305-class_cleanup-mips-v1-1-e93726711468@marliere.net>
References: <20240305-class_cleanup-mips-v1-0-e93726711468@marliere.net>
In-Reply-To: <20240305-class_cleanup-mips-v1-0-e93726711468@marliere.net>
To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, 
 Greg Kroah-Hartman <gregkh@linuxfoundation.org>, 
 "Ricardo B. Marliere" <ricardo@marliere.net>

Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the mt_class structure to be declared at build time placing
it into read-only memory, instead of having to be dynamically allocated at
boot time.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
---
KTODO: use device_register instead of device_create?
---
 arch/mips/include/asm/mips_mt.h |  2 +-
 arch/mips/kernel/mips-mt.c      | 14 ++++----------
 arch/mips/kernel/rtlx-mt.c      |  8 ++++----
 3 files changed, 9 insertions(+), 15 deletions(-)

diff --git a/arch/mips/include/asm/mips_mt.h b/arch/mips/include/asm/mips_mt.h
index b444523ecd50..28917f1582b3 100644
--- a/arch/mips/include/asm/mips_mt.h
+++ b/arch/mips/include/asm/mips_mt.h
@@ -26,6 +26,6 @@ static inline void mips_mt_set_cpuoptions(void) { }
 #endif
 
 struct class;
-extern struct class *mt_class;
+extern const struct class mt_class;
 
 #endif /* __ASM_MIPS_MT_H */
diff --git a/arch/mips/kernel/mips-mt.c b/arch/mips/kernel/mips-mt.c
index c07d64438b5b..c938ba208fc0 100644
--- a/arch/mips/kernel/mips-mt.c
+++ b/arch/mips/kernel/mips-mt.c
@@ -229,19 +229,13 @@ void mips_mt_set_cpuoptions(void)
 	}
 }
 
-struct class *mt_class;
+const struct class mt_class = {
+	.name = "mt",
+};
 
 static int __init mips_mt_init(void)
 {
-	struct class *mtc;
-
-	mtc = class_create("mt");
-	if (IS_ERR(mtc))
-		return PTR_ERR(mtc);
-
-	mt_class = mtc;
-
-	return 0;
+	return class_register(&mt_class);
 }
 
 subsys_initcall(mips_mt_init);
diff --git a/arch/mips/kernel/rtlx-mt.c b/arch/mips/kernel/rtlx-mt.c
index 38c6925a1bea..ff7535de42ca 100644
--- a/arch/mips/kernel/rtlx-mt.c
+++ b/arch/mips/kernel/rtlx-mt.c
@@ -95,11 +95,11 @@ int __init rtlx_module_init(void)
 		atomic_set(&channel_wqs[i].in_open, 0);
 		mutex_init(&channel_wqs[i].mutex);
 
-		dev = device_create(mt_class, NULL, MKDEV(major, i), NULL,
+		dev = device_create(&mt_class, NULL, MKDEV(major, i), NULL,
 				    "%s%d", RTLX_MODULE_NAME, i);
 		if (IS_ERR(dev)) {
 			while (i--)
-				device_destroy(mt_class, MKDEV(major, i));
+				device_destroy(&mt_class, MKDEV(major, i));
 
 			err = PTR_ERR(dev);
 			goto out_chrdev;
@@ -127,7 +127,7 @@ int __init rtlx_module_init(void)
 
 out_class:
 	for (i = 0; i < RTLX_CHANNELS; i++)
-		device_destroy(mt_class, MKDEV(major, i));
+		device_destroy(&mt_class, MKDEV(major, i));
 out_chrdev:
 	unregister_chrdev(major, RTLX_MODULE_NAME);
 
@@ -139,7 +139,7 @@ void __exit rtlx_module_exit(void)
 	int i;
 
 	for (i = 0; i < RTLX_CHANNELS; i++)
-		device_destroy(mt_class, MKDEV(major, i));
+		device_destroy(&mt_class, MKDEV(major, i));
 
 	unregister_chrdev(major, RTLX_MODULE_NAME);
 

-- 
2.43.0