mips: mt: make mt_class constant

Since commit 43a7206 ("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>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

Author: rbmarliere

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 */

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);

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);