From 5b87c058bf67905fcadf7b0a0786a6989e604cab Mon Sep 17 00:00:00 2001 From: Ivan Orlov Date: Tue, 20 Jun 2023 16:44:33 +0200 Subject: [PATCH] x86/MSR: make msr_class a static const structure Now that the driver core allows for struct class to be in read-only memory, move the msr_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: "H. Peter Anvin" Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: x86@kernel.org Suggested-by: Greg Kroah-Hartman Signed-off-by: Ivan Orlov Link: https://lore.kernel.org/r/20230620144431.583290-5-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/msr.c | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-) diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c index 7bb17d37db01..e17c16c54a37 100644 --- a/arch/x86/kernel/msr.c +++ b/arch/x86/kernel/msr.c @@ -39,7 +39,6 @@ #include #include -static struct class *msr_class; static enum cpuhp_state cpuhp_msr_state; enum allow_write_msrs { @@ -235,26 +234,31 @@ static const struct file_operations msr_fops = { .compat_ioctl = msr_ioctl, }; +static char *msr_devnode(const struct device *dev, umode_t *mode) +{ + return kasprintf(GFP_KERNEL, "cpu/%u/msr", MINOR(dev->devt)); +} + +static const struct class msr_class = { + .name = "msr", + .devnode = msr_devnode, +}; + static int msr_device_create(unsigned int cpu) { struct device *dev; - dev = device_create(msr_class, NULL, MKDEV(MSR_MAJOR, cpu), NULL, + dev = device_create(&msr_class, NULL, MKDEV(MSR_MAJOR, cpu), NULL, "msr%d", cpu); return PTR_ERR_OR_ZERO(dev); } static int msr_device_destroy(unsigned int cpu) { - device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu)); + device_destroy(&msr_class, MKDEV(MSR_MAJOR, cpu)); return 0; } -static char *msr_devnode(const struct device *dev, umode_t *mode) -{ - return kasprintf(GFP_KERNEL, "cpu/%u/msr", MINOR(dev->devt)); -} - static int __init msr_init(void) { int err; @@ -263,12 +267,9 @@ static int __init msr_init(void) pr_err("unable to get major %d for msr\n", MSR_MAJOR); return -EBUSY; } - msr_class = class_create("msr"); - if (IS_ERR(msr_class)) { - err = PTR_ERR(msr_class); + err = class_register(&msr_class); + if (err) goto out_chrdev; - } - msr_class->devnode = msr_devnode; err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/msr:online", msr_device_create, msr_device_destroy); @@ -278,7 +279,7 @@ static int __init msr_init(void) return 0; out_class: - class_destroy(msr_class); + class_unregister(&msr_class); out_chrdev: __unregister_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr"); return err; @@ -288,7 +289,7 @@ module_init(msr_init); static void __exit msr_exit(void) { cpuhp_remove_state(cpuhp_msr_state); - class_destroy(msr_class); + class_unregister(&msr_class); __unregister_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr"); } module_exit(msr_exit)