From 574b851e99923c884fee4e0d7cf7e7c3dc023ffa Mon Sep 17 00:00:00 2001 From: Toshi Kani Date: Thu, 29 Aug 2013 18:22:07 -0600 Subject: hotplug / x86: Add hotplug lock to missing places lock_device_hotplug[_sysfs]() serializes CPU & Memory online/offline and hotplug operations. However, this lock is not held in the debug interfaces below that initiate CPU online/offline operations. - _debug_hotplug_cpu(), cpu0 hotplug test interface enabled by CONFIG_DEBUG_HOTPLUG_CPU0. - cpu_probe_store() and cpu_release_store(), cpu hotplug test interface enabled by CONFIG_ARCH_CPU_PROBE_RELEASE. This patch changes the above interfaces to hold lock_device_hotplug(). Signed-off-by: Toshi Kani Acked-by: Greg Kroah-Hartman Acked-by: Yasuaki Ishimatsu Signed-off-by: Rafael J. Wysocki --- drivers/base/cpu.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) (limited to 'drivers/base') diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 848ebbd25717..51f5d7fe2f0b 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -93,7 +93,17 @@ static ssize_t cpu_probe_store(struct device *dev, const char *buf, size_t count) { - return arch_cpu_probe(buf, count); + ssize_t cnt; + int ret; + + ret = lock_device_hotplug_sysfs(); + if (ret) + return ret; + + cnt = arch_cpu_probe(buf, count); + + unlock_device_hotplug(); + return cnt; } static ssize_t cpu_release_store(struct device *dev, @@ -101,7 +111,17 @@ static ssize_t cpu_release_store(struct device *dev, const char *buf, size_t count) { - return arch_cpu_release(buf, count); + ssize_t cnt; + int ret; + + ret = lock_device_hotplug_sysfs(); + if (ret) + return ret; + + cnt = arch_cpu_release(buf, count); + + unlock_device_hotplug(); + return cnt; } static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store); -- cgit From 6dedcca610c6d6189b4a54d32118d1654adb73d2 Mon Sep 17 00:00:00 2001 From: Toshi Kani Date: Wed, 25 Sep 2013 15:08:27 -0600 Subject: hotplug, powerpc, x86: Remove cpu_hotplug_driver_lock() cpu_hotplug_driver_lock() serializes CPU online/offline operations when ARCH_CPU_PROBE_RELEASE is set. This lock interface is no longer necessary with the following reason: - lock_device_hotplug() now protects CPU online/offline operations, including the probe & release interfaces enabled by ARCH_CPU_PROBE_RELEASE. The use of cpu_hotplug_driver_lock() is redundant. - cpu_hotplug_driver_lock() is only valid when ARCH_CPU_PROBE_RELEASE is defined, which is misleading and is only enabled on powerpc. This patch removes the cpu_hotplug_driver_lock() interface. As a result, ARCH_CPU_PROBE_RELEASE only enables / disables the cpu probe & release interface as intended. There is no functional change in this patch. Signed-off-by: Toshi Kani Reviewed-by: Nathan Fontenot Signed-off-by: Rafael J. Wysocki --- drivers/base/cpu.c | 15 +++------------ 1 file changed, 3 insertions(+), 12 deletions(-) (limited to 'drivers/base') diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 51f5d7fe2f0b..f48370dfc908 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -44,13 +44,11 @@ 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 = -ENODEV; - - cpu_hotplug_driver_lock(); + int ret; from_nid = cpu_to_node(cpuid); if (from_nid == NUMA_NO_NODE) - goto out; + return -ENODEV; ret = cpu_up(cpuid); /* @@ -61,19 +59,12 @@ static int __ref cpu_subsys_online(struct device *dev) if (from_nid != to_nid) change_cpu_under_node(cpu, from_nid, to_nid); - out: - cpu_hotplug_driver_unlock(); return ret; } static int cpu_subsys_offline(struct device *dev) { - int ret; - - cpu_hotplug_driver_lock(); - ret = cpu_down(dev->id); - cpu_hotplug_driver_unlock(); - return ret; + return cpu_down(dev->id); } void unregister_cpu(struct cpu *cpu) -- cgit