From c0d64cb031c21f163a0ec15cf10844bcf0ceedcf Mon Sep 17 00:00:00 2001 From: Len Brown Date: Sat, 22 May 2010 16:34:10 -0400 Subject: cpuidle: add cpuidle_unregister_driver() error check Assure that cpuidle_unregister_driver() will not clobber the registered driver if unregistered by somebody else. Signed-off-by: Len Brown --- drivers/cpuidle/driver.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'drivers/cpuidle') diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c index 2257004fe33d..826b5c0aa12b 100644 --- a/drivers/cpuidle/driver.c +++ b/drivers/cpuidle/driver.c @@ -45,8 +45,11 @@ EXPORT_SYMBOL_GPL(cpuidle_register_driver); */ void cpuidle_unregister_driver(struct cpuidle_driver *drv) { - if (!drv) + if (drv != cpuidle_curr_driver) { + WARN(1, "invalid cpuidle_unregister_driver(%s)\n", + drv->name); return; + } spin_lock(&cpuidle_driver_lock); cpuidle_curr_driver = NULL; -- cgit v1.2.2 From 752138df0dc2daaae09379c754caeb08c97905dc Mon Sep 17 00:00:00 2001 From: Len Brown Date: Sat, 22 May 2010 16:57:26 -0400 Subject: cpuidle: make cpuidle_curr_driver static cpuidle_register_driver() sets cpuidle_curr_driver cpuidle_unregister_driver() clears cpuidle_curr_driver We should't expose cpuidle_curr_driver to potential modification except via these interfaces. So make it static and create cpuidle_get_driver() to observe it. Signed-off-by: Len Brown --- drivers/cpuidle/cpuidle.c | 12 +++++++----- drivers/cpuidle/cpuidle.h | 1 - drivers/cpuidle/driver.c | 11 ++++++++++- drivers/cpuidle/sysfs.c | 5 +++-- 4 files changed, 20 insertions(+), 9 deletions(-) (limited to 'drivers/cpuidle') diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 12fdd3987a36..199488576a05 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -156,7 +156,7 @@ int cpuidle_enable_device(struct cpuidle_device *dev) if (dev->enabled) return 0; - if (!cpuidle_curr_driver || !cpuidle_curr_governor) + if (!cpuidle_get_driver() || !cpuidle_curr_governor) return -EIO; if (!dev->state_count) return -EINVAL; @@ -207,7 +207,7 @@ void cpuidle_disable_device(struct cpuidle_device *dev) { if (!dev->enabled) return; - if (!cpuidle_curr_driver || !cpuidle_curr_governor) + if (!cpuidle_get_driver() || !cpuidle_curr_governor) return; dev->enabled = 0; @@ -271,10 +271,11 @@ static int __cpuidle_register_device(struct cpuidle_device *dev) { int ret; struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu); + struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver(); if (!sys_dev) return -EINVAL; - if (!try_module_get(cpuidle_curr_driver->owner)) + if (!try_module_get(cpuidle_driver->owner)) return -EINVAL; init_completion(&dev->kobj_unregister); @@ -284,7 +285,7 @@ static int __cpuidle_register_device(struct cpuidle_device *dev) per_cpu(cpuidle_devices, dev->cpu) = dev; list_add(&dev->device_list, &cpuidle_detected_devices); if ((ret = cpuidle_add_sysfs(sys_dev))) { - module_put(cpuidle_curr_driver->owner); + module_put(cpuidle_driver->owner); return ret; } @@ -325,6 +326,7 @@ EXPORT_SYMBOL_GPL(cpuidle_register_device); void cpuidle_unregister_device(struct cpuidle_device *dev) { struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu); + struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver(); if (dev->registered == 0) return; @@ -340,7 +342,7 @@ void cpuidle_unregister_device(struct cpuidle_device *dev) cpuidle_resume_and_unlock(); - module_put(cpuidle_curr_driver->owner); + module_put(cpuidle_driver->owner); } EXPORT_SYMBOL_GPL(cpuidle_unregister_device); diff --git a/drivers/cpuidle/cpuidle.h b/drivers/cpuidle/cpuidle.h index 9476ba33ee2c..33e50d556f17 100644 --- a/drivers/cpuidle/cpuidle.h +++ b/drivers/cpuidle/cpuidle.h @@ -9,7 +9,6 @@ /* For internal use only */ extern struct cpuidle_governor *cpuidle_curr_governor; -extern struct cpuidle_driver *cpuidle_curr_driver; extern struct list_head cpuidle_governors; extern struct list_head cpuidle_detected_devices; extern struct mutex cpuidle_lock; diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c index 826b5c0aa12b..fd1601e3d125 100644 --- a/drivers/cpuidle/driver.c +++ b/drivers/cpuidle/driver.c @@ -14,7 +14,7 @@ #include "cpuidle.h" -struct cpuidle_driver *cpuidle_curr_driver; +static struct cpuidle_driver *cpuidle_curr_driver; DEFINE_SPINLOCK(cpuidle_driver_lock); /** @@ -39,6 +39,15 @@ int cpuidle_register_driver(struct cpuidle_driver *drv) EXPORT_SYMBOL_GPL(cpuidle_register_driver); +/** + * cpuidle_get_driver - return the current driver + */ +struct cpuidle_driver *cpuidle_get_driver(void) +{ + return cpuidle_curr_driver; +} +EXPORT_SYMBOL_GPL(cpuidle_get_driver); + /** * cpuidle_unregister_driver - unregisters a driver * @drv: the driver diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c index 0ba9c8b8ee74..0310ffaec9df 100644 --- a/drivers/cpuidle/sysfs.c +++ b/drivers/cpuidle/sysfs.c @@ -47,10 +47,11 @@ static ssize_t show_current_driver(struct sysdev_class *class, char *buf) { ssize_t ret; + struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver(); spin_lock(&cpuidle_driver_lock); - if (cpuidle_curr_driver) - ret = sprintf(buf, "%s\n", cpuidle_curr_driver->name); + if (cpuidle_driver) + ret = sprintf(buf, "%s\n", cpuidle_driver->name); else ret = sprintf(buf, "none\n"); spin_unlock(&cpuidle_driver_lock); -- cgit v1.2.2