Messages in this thread | | | Date | Thu, 16 Jun 2016 17:43:11 +0100 | From | Will Deacon <> | Subject | Re: [PATCH v5] arm64: cpuinfo: Expose MIDR_EL1 and REVIDR_EL1 to sysfs |
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On Thu, Jun 16, 2016 at 02:28:50PM +0100, Suzuki K Poulose wrote: > +static int __init cpuinfo_regs_init(void) > +{ > + int cpu, finalcpu, ret; > + struct device *dev; > + > + cpu_hotplug_disable(); > + > + for_each_present_cpu(cpu) { > + dev = get_cpu_device(cpu); > + > + if (!dev) { > + ret = -ENODEV; > + break; > + } > + > + ret = sysfs_create_group(&dev->kobj, &cpuregs_attr_group); > + if (ret) > + break; > + } > + > + if (!ret) > + goto out; > + /* > + * We were unable to put down sysfs groups for all the CPUs, revert > + * all the groups we have placed down s.t. none are visible. > + * Otherwise we could give a misleading picture of what's present. > + */ > + finalcpu = cpu; > + for_each_present_cpu(cpu) { > + if (cpu == finalcpu) > + break; > + dev = get_cpu_device(cpu); > + if (dev) > + sysfs_remove_group(&dev->kobj, &cpuregs_attr_group); > + } > + > +out: > + cpu_hotplug_enable(); > + return ret; > +} > + > +device_initcall(cpuinfo_regs_init);
Given that you're built the sysfs entries out of the present mask, don't you need a hotplug notifier to keep things up to date?
Will
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