From 0902a9044fa5b7a0456ea4daacec2c2b3189ba8c Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 3 May 2013 00:25:49 +0200 Subject: Driver core: Use generic offline/online for CPU offline/online Rework the CPU hotplug code in drivers/base/cpu.c to use the generic offline/online support introduced previously instead of its own CPU-specific code. For this purpose, modify cpu_subsys to provide offline and online callbacks for CONFIG_HOTPLUG_CPU set and remove the code handling the CPU-specific 'online' sysfs attribute. This modification is not supposed to change the user-observable behavior of the kernel (i.e. the 'online' attribute will be present in exactly the same place in sysfs and should trigger exactly the same actions as before). Signed-off-by: Rafael J. Wysocki Acked-by: Greg Kroah-Hartman Reviewed-by: Toshi Kani --- drivers/base/cpu.c | 89 ++++++++++++++++++++---------------------------------- 1 file changed, 32 insertions(+), 57 deletions(-) (limited to 'drivers/base/cpu.c') diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 3d48fc887ef4..25c8768172e9 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -16,12 +16,6 @@ #include "base.h" -struct bus_type cpu_subsys = { - .name = "cpu", - .dev_name = "cpu", -}; -EXPORT_SYMBOL_GPL(cpu_subsys); - static DEFINE_PER_CPU(struct device *, cpu_sys_devices); #ifdef CONFIG_HOTPLUG_CPU @@ -34,69 +28,45 @@ static void change_cpu_under_node(struct cpu *cpu, cpu->node_id = to_nid; } -static ssize_t show_online(struct device *dev, - struct device_attribute *attr, - char *buf) +static int __ref cpu_subsys_online(struct device *dev) { struct cpu *cpu = container_of(dev, struct cpu, dev); + int cpuid = dev->id; + int from_nid, to_nid; + int ret; + + cpu_hotplug_driver_lock(); + + from_nid = cpu_to_node(cpuid); + ret = cpu_up(cpuid); + /* + * When hot adding memory to memoryless node and enabling a cpu + * on the node, node number of the cpu may internally change. + */ + to_nid = cpu_to_node(cpuid); + if (from_nid != to_nid) + change_cpu_under_node(cpu, from_nid, to_nid); - return sprintf(buf, "%u\n", !!cpu_online(cpu->dev.id)); + cpu_hotplug_driver_unlock(); + return ret; } -static ssize_t __ref store_online(struct device *dev, - struct device_attribute *attr, - const char *buf, size_t count) +static int cpu_subsys_offline(struct device *dev) { - struct cpu *cpu = container_of(dev, struct cpu, dev); - int cpuid = cpu->dev.id; - int from_nid, to_nid; - ssize_t ret; + int ret; cpu_hotplug_driver_lock(); - switch (buf[0]) { - case '0': - ret = cpu_down(cpuid); - if (!ret) - kobject_uevent(&dev->kobj, KOBJ_OFFLINE); - break; - case '1': - from_nid = cpu_to_node(cpuid); - ret = cpu_up(cpuid); - - /* - * When hot adding memory to memoryless node and enabling a cpu - * on the node, node number of the cpu may internally change. - */ - to_nid = cpu_to_node(cpuid); - if (from_nid != to_nid) - change_cpu_under_node(cpu, from_nid, to_nid); - - if (!ret) - kobject_uevent(&dev->kobj, KOBJ_ONLINE); - break; - default: - ret = -EINVAL; - } + ret = cpu_down(dev->id); cpu_hotplug_driver_unlock(); - - if (ret >= 0) - ret = count; return ret; } -static DEVICE_ATTR(online, 0644, show_online, store_online); -static void __cpuinit register_cpu_control(struct cpu *cpu) -{ - device_create_file(&cpu->dev, &dev_attr_online); -} void unregister_cpu(struct cpu *cpu) { int logical_cpu = cpu->dev.id; unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu)); - device_remove_file(&cpu->dev, &dev_attr_online); - device_unregister(&cpu->dev); per_cpu(cpu_sys_devices, logical_cpu) = NULL; return; @@ -123,12 +93,18 @@ static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store); static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store); #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */ -#else /* ... !CONFIG_HOTPLUG_CPU */ -static inline void register_cpu_control(struct cpu *cpu) -{ -} #endif /* CONFIG_HOTPLUG_CPU */ +struct bus_type cpu_subsys = { + .name = "cpu", + .dev_name = "cpu", +#ifdef CONFIG_HOTPLUG_CPU + .online = cpu_subsys_online, + .offline = cpu_subsys_offline, +#endif +}; +EXPORT_SYMBOL_GPL(cpu_subsys); + #ifdef CONFIG_KEXEC #include @@ -277,12 +253,11 @@ int __cpuinit register_cpu(struct cpu *cpu, int num) cpu->dev.id = num; cpu->dev.bus = &cpu_subsys; cpu->dev.release = cpu_device_release; + cpu->dev.offline_disabled = !cpu->hotpluggable; #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE cpu->dev.bus->uevent = arch_cpu_uevent; #endif error = device_register(&cpu->dev); - if (!error && cpu->hotpluggable) - register_cpu_control(cpu); if (!error) per_cpu(cpu_sys_devices, num) = &cpu->dev; if (!error) -- cgit v1.2.3 From ac212b6980d8d5eda705864fc5a8ecddc6d6eacc Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 3 May 2013 00:26:22 +0200 Subject: ACPI / processor: Use common hotplug infrastructure Split the ACPI processor driver into two parts, one that is non-modular, resides in the ACPI core and handles the enumeration and hotplug of processors and one that implements the rest of the existing processor driver functionality. The non-modular part uses an ACPI scan handler object to enumerate processors on the basis of information provided by the ACPI namespace and to hook up with the common ACPI hotplug infrastructure. It also populates the ACPI handle of each processor device having a corresponding object in the ACPI namespace, which allows the driver proper to bind to those devices, and makes the driver bind to them if it is readily available (i.e. loaded) when the scan handler's .attach() routine is running. There are a few reasons to make this change. First, switching the ACPI processor driver to using the common ACPI hotplug infrastructure reduces code duplication and size considerably, even though a new file is created along with a header comment etc. Second, since the common hotplug code attempts to offline devices before starting the (non-reversible) removal procedure, it will abort (and possibly roll back) hot-remove operations involving processors if cpu_down() returns an error code for one of them instead of continuing them blindly (if /sys/firmware/acpi/hotplug/force_remove is unset). That is a more desirable behavior than what the current code does. Finally, the separation of the scan/hotplug part from the driver proper makes it possible to simplify the driver's .remove() routine, because it doesn't need to worry about the possible cleanup related to processor removal any more (the scan/hotplug part is responsible for that now) and can handle device removal and driver removal symmetricaly (i.e. as appropriate). Some user-visible changes in sysfs are made (for example, the 'sysdev' link from the ACPI device node to the processor device's directory is gone and a 'physical_node' link is present instead and a corresponding 'firmware_node' is present in the processor device's directory, the processor driver is now visible under /sys/bus/cpu/drivers/ and bound to the processor device), but that shouldn't affect the functionality that users care about (frequency scaling, C-states and thermal management). Tested on my venerable Toshiba Portege R500. Signed-off-by: Rafael J. Wysocki Acked-by: Greg Kroah-Hartman Reviewed-by: Toshi Kani --- drivers/base/cpu.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'drivers/base/cpu.c') diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 25c8768172e9..7431ba6fc2d4 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -13,11 +13,21 @@ #include #include #include +#include #include "base.h" static DEFINE_PER_CPU(struct device *, cpu_sys_devices); +static int cpu_subsys_match(struct device *dev, struct device_driver *drv) +{ + /* ACPI style match is the only one that may succeed. */ + if (acpi_driver_match_device(dev, drv)) + return 1; + + return 0; +} + #ifdef CONFIG_HOTPLUG_CPU static void change_cpu_under_node(struct cpu *cpu, unsigned int from_nid, unsigned int to_nid) @@ -98,6 +108,7 @@ static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store); struct bus_type cpu_subsys = { .name = "cpu", .dev_name = "cpu", + .match = cpu_subsys_match, #ifdef CONFIG_HOTPLUG_CPU .online = cpu_subsys_online, .offline = cpu_subsys_offline, -- cgit v1.2.3 From 1001b4d4a8ee6b2e7a6078a02ccdf68f91b192bd Mon Sep 17 00:00:00 2001 From: Toshi Kani Date: Thu, 30 May 2013 00:30:05 +0200 Subject: CPU: Fix sysfs cpu/online of offlined CPUs As reported by Dave Hansen, sysfs cpu/online shows 1 for offlined CPUs at boot. Fix this problem by initializing dev.offline with cpu_online() when registering a CPU. References: https://lkml.org/lkml/2013/5/29/403 Reported-and-tested-by: Dave Hansen Signed-off-by: Toshi Kani Signed-off-by: Rafael J. Wysocki --- drivers/base/cpu.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/base/cpu.c') diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 7431ba6fc2d4..1d110dc6f0c1 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -265,6 +265,7 @@ int __cpuinit register_cpu(struct cpu *cpu, int num) cpu->dev.bus = &cpu_subsys; cpu->dev.release = cpu_device_release; cpu->dev.offline_disabled = !cpu->hotpluggable; + cpu->dev.offline = !cpu_online(num); #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE cpu->dev.bus->uevent = arch_cpu_uevent; #endif -- cgit v1.2.3