diff options
| -rw-r--r-- | drivers/base/power/qos.c | 67 |
1 files changed, 41 insertions, 26 deletions
diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c index 74a67e0019a2..968a77145e81 100644 --- a/drivers/base/power/qos.c +++ b/drivers/base/power/qos.c @@ -24,26 +24,32 @@ * . a system-wide notification callback using the dev_pm_qos_*_global_notifier * API. The notification chain data is stored in a static variable. * - * Note about the per-device constraint data struct allocation: - * . The per-device constraints data struct ptr is tored into the device + * Notes about the per-device constraint data struct allocation: + * . The per-device constraints data struct ptr is stored into the device * dev_pm_info. * . To minimize the data usage by the per-device constraints, the data struct - * is only allocated at the first call to dev_pm_qos_add_request. + * is only allocated at the first call to dev_pm_qos_add_request. * . The data is later free'd when the device is removed from the system. - * . A global mutex protects the constraints users from the data being - * allocated and free'd. + * + * Notes about locking: + * . The dev->power.lock lock protects the constraints list + * (dev->power.constraints) allocation and free, as triggered by the + * driver core code at device insertion and removal, + * . A global lock dev_pm_qos_lock protects the constraints list entries + * from any modification and the notifiers registration and unregistration. + * . For both locks a spinlock is needed since this code can be called from + * interrupt context or spinlock protected context. */ #include <linux/pm_qos.h> #include <linux/spinlock.h> #include <linux/slab.h> #include <linux/device.h> -#include <linux/mutex.h> #include <linux/export.h> #include "power.h" -static DEFINE_MUTEX(dev_pm_qos_mtx); +static DEFINE_SPINLOCK(dev_pm_qos_lock); static BLOCKING_NOTIFIER_HEAD(dev_pm_notifiers); @@ -110,18 +116,19 @@ static int apply_constraint(struct dev_pm_qos_request *req, * @dev: device to allocate data for * * Called at the first call to add_request, for constraint data allocation - * Must be called with the dev_pm_qos_mtx mutex held + * Must be called with the dev_pm_qos_lock lock held */ static int dev_pm_qos_constraints_allocate(struct device *dev) { struct pm_qos_constraints *c; struct blocking_notifier_head *n; + unsigned long flags; - c = kzalloc(sizeof(*c), GFP_KERNEL); + c = kzalloc(sizeof(*c), GFP_ATOMIC); if (!c) return -ENOMEM; - n = kzalloc(sizeof(*n), GFP_KERNEL); + n = kzalloc(sizeof(*n), GFP_ATOMIC); if (!n) { kfree(c); return -ENOMEM; @@ -134,9 +141,9 @@ static int dev_pm_qos_constraints_allocate(struct device *dev) c->type = PM_QOS_MIN; c->notifiers = n; - spin_lock_irq(&dev->power.lock); + spin_lock_irqsave(&dev->power.lock, flags); dev->power.constraints = c; - spin_unlock_irq(&dev->power.lock); + spin_unlock_irqrestore(&dev->power.lock, flags); return 0; } @@ -150,10 +157,12 @@ static int dev_pm_qos_constraints_allocate(struct device *dev) */ void dev_pm_qos_constraints_init(struct device *dev) { - mutex_lock(&dev_pm_qos_mtx); + unsigned long flags; + + spin_lock_irqsave(&dev_pm_qos_lock, flags); dev->power.constraints = NULL; dev->power.power_state = PMSG_ON; - mutex_unlock(&dev_pm_qos_mtx); + spin_unlock_irqrestore(&dev_pm_qos_lock, flags); } /** @@ -166,6 +175,7 @@ void dev_pm_qos_constraints_destroy(struct device *dev) { struct dev_pm_qos_request *req, *tmp; struct pm_qos_constraints *c; + unsigned long flags; /* * If the device's PM QoS resume latency limit has been exposed to user @@ -173,7 +183,7 @@ void dev_pm_qos_constraints_destroy(struct device *dev) */ dev_pm_qos_hide_latency_limit(dev); - mutex_lock(&dev_pm_qos_mtx); + spin_lock_irqsave(&dev_pm_qos_lock, flags); dev->power.power_state = PMSG_INVALID; c = dev->power.constraints; @@ -198,7 +208,7 @@ void dev_pm_qos_constraints_destroy(struct device *dev) kfree(c); out: - mutex_unlock(&dev_pm_qos_mtx); + spin_unlock_irqrestore(&dev_pm_qos_lock, flags); } /** @@ -223,6 +233,7 @@ int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req, s32 value) { int ret = 0; + unsigned long flags; if (!dev || !req) /*guard against callers passing in null */ return -EINVAL; @@ -233,7 +244,7 @@ int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req, req->dev = dev; - mutex_lock(&dev_pm_qos_mtx); + spin_lock_irqsave(&dev_pm_qos_lock, flags); if (!dev->power.constraints) { if (dev->power.power_state.event == PM_EVENT_INVALID) { @@ -255,7 +266,7 @@ int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req, ret = apply_constraint(req, PM_QOS_ADD_REQ, value); out: - mutex_unlock(&dev_pm_qos_mtx); + spin_unlock_irqrestore(&dev_pm_qos_lock, flags); return ret; } @@ -280,6 +291,7 @@ int dev_pm_qos_update_request(struct dev_pm_qos_request *req, s32 new_value) { int ret = 0; + unsigned long flags; if (!req) /*guard against callers passing in null */ return -EINVAL; @@ -288,7 +300,7 @@ int dev_pm_qos_update_request(struct dev_pm_qos_request *req, "%s() called for unknown object\n", __func__)) return -EINVAL; - mutex_lock(&dev_pm_qos_mtx); + spin_lock_irqsave(&dev_pm_qos_lock, flags); if (req->dev->power.constraints) { if (new_value != req->node.prio) @@ -299,7 +311,7 @@ int dev_pm_qos_update_request(struct dev_pm_qos_request *req, ret = -ENODEV; } - mutex_unlock(&dev_pm_qos_mtx); + spin_unlock_irqrestore(&dev_pm_qos_lock, flags); return ret; } EXPORT_SYMBOL_GPL(dev_pm_qos_update_request); @@ -319,6 +331,7 @@ EXPORT_SYMBOL_GPL(dev_pm_qos_update_request); int dev_pm_qos_remove_request(struct dev_pm_qos_request *req) { int ret = 0; + unsigned long flags; if (!req) /*guard against callers passing in null */ return -EINVAL; @@ -327,7 +340,7 @@ int dev_pm_qos_remove_request(struct dev_pm_qos_request *req) "%s() called for unknown object\n", __func__)) return -EINVAL; - mutex_lock(&dev_pm_qos_mtx); + spin_lock_irqsave(&dev_pm_qos_lock, flags); if (req->dev->power.constraints) { ret = apply_constraint(req, PM_QOS_REMOVE_REQ, @@ -338,7 +351,7 @@ int dev_pm_qos_remove_request(struct dev_pm_qos_request *req) ret = -ENODEV; } - mutex_unlock(&dev_pm_qos_mtx); + spin_unlock_irqrestore(&dev_pm_qos_lock, flags); return ret; } EXPORT_SYMBOL_GPL(dev_pm_qos_remove_request); @@ -359,8 +372,9 @@ EXPORT_SYMBOL_GPL(dev_pm_qos_remove_request); int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier) { int ret = 0; + unsigned long flags; - mutex_lock(&dev_pm_qos_mtx); + spin_lock_irqsave(&dev_pm_qos_lock, flags); if (!dev->power.constraints) ret = dev->power.power_state.event != PM_EVENT_INVALID ? @@ -370,7 +384,7 @@ int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier) ret = blocking_notifier_chain_register( dev->power.constraints->notifiers, notifier); - mutex_unlock(&dev_pm_qos_mtx); + spin_unlock_irqrestore(&dev_pm_qos_lock, flags); return ret; } EXPORT_SYMBOL_GPL(dev_pm_qos_add_notifier); @@ -389,8 +403,9 @@ int dev_pm_qos_remove_notifier(struct device *dev, struct notifier_block *notifier) { int retval = 0; + unsigned long flags; - mutex_lock(&dev_pm_qos_mtx); + spin_lock_irqsave(&dev_pm_qos_lock, flags); /* Silently return if the constraints object is not present. */ if (dev->power.constraints) @@ -398,7 +413,7 @@ int dev_pm_qos_remove_notifier(struct device *dev, dev->power.constraints->notifiers, notifier); - mutex_unlock(&dev_pm_qos_mtx); + spin_unlock_irqrestore(&dev_pm_qos_lock, flags); return retval; } EXPORT_SYMBOL_GPL(dev_pm_qos_remove_notifier); |