From ad74557a49d1dea428fb0ad60e75a5aa37610e1d Mon Sep 17 00:00:00 2001 From: Ashok Raj Date: Sun, 30 Oct 2005 14:59:49 -0800 Subject: [PATCH] [PATCH] introduce get_cpu_sysdev() to retrieve a sysfs entry for a cpu. Some modules creating sysfs entries under /sys/devices/system/cpu/cpuX/ need to know the parent sysfs entry to make devices under them. This will just return the sysfs entry for a given cpu. sysfs entries showing under each cpu sysfs can be easily created if such entries can be created by registering a sysfs driver for cpuclass. The issue is when the entry is created the CPU may not be online, hence we would need to defer the creation until the online notification comes. Current users: cache entries for Intel CPU's and cpufreq subsystem. Signed-off-by: Ashok Raj Signed-off-by: Venkatesh Pallipadi Cc: Dave Jones Cc: Zwane Mwaikambo Cc: Greg KH Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/base/cpu.c | 16 ++++++++++++++-- include/linux/cpu.h | 1 + 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 081c927b1ed8..a95844790f7b 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -16,6 +16,8 @@ struct sysdev_class cpu_sysdev_class = { }; EXPORT_SYMBOL(cpu_sysdev_class); +static struct sys_device *cpu_sys_devices[NR_CPUS]; + #ifdef CONFIG_HOTPLUG_CPU int __attribute__((weak)) smp_prepare_cpu (int cpu) { @@ -64,6 +66,7 @@ static void __devinit register_cpu_control(struct cpu *cpu) } void unregister_cpu(struct cpu *cpu, struct node *root) { + int logical_cpu = cpu->sysdev.id; if (root) sysfs_remove_link(&root->sysdev.kobj, @@ -71,7 +74,7 @@ void unregister_cpu(struct cpu *cpu, struct node *root) sysdev_remove_file(&cpu->sysdev, &attr_online); sysdev_unregister(&cpu->sysdev); - + cpu_sys_devices[logical_cpu] = NULL; return; } #else /* ... !CONFIG_HOTPLUG_CPU */ @@ -103,10 +106,19 @@ int __devinit register_cpu(struct cpu *cpu, int num, struct node *root) kobject_name(&cpu->sysdev.kobj)); if (!error && !cpu->no_control) register_cpu_control(cpu); + if (!error) + cpu_sys_devices[num] = &cpu->sysdev; return error; } - +struct sys_device *get_cpu_sysdev(int cpu) +{ + if (cpu < NR_CPUS) + return cpu_sys_devices[cpu]; + else + return NULL; +} +EXPORT_SYMBOL_GPL(get_cpu_sysdev); int __init cpu_dev_init(void) { diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 86980c68234a..1f7b2c097503 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -32,6 +32,7 @@ struct cpu { }; extern int register_cpu(struct cpu *, int, struct node *); +extern struct sys_device *get_cpu_sysdev(int cpu); #ifdef CONFIG_HOTPLUG_CPU extern void unregister_cpu(struct cpu *, struct node *); #endif -- 2.20.1