Revert "PM QoS: Use spinlock in the per-device PM QoS constraints code"
This reverts commit fc2fb3a075.
The problem with the above commit is that it makes the device PM QoS
core code hold a spinlock around blocking_notifier_call_chain()
invocations.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This commit is contained in:
Rafael J. Wysocki
Родитель
fc2fb3a075
Коммит
8376869e51
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@ -24,32 +24,26 @@
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* . a system-wide notification callback using the dev_pm_qos_*_global_notifier
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* API. The notification chain data is stored in a static variable.
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*
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* Notes about the per-device constraint data struct allocation:
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* . The per-device constraints data struct ptr is stored into the device
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* Note about the per-device constraint data struct allocation:
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* . The per-device constraints data struct ptr is tored into the device
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* dev_pm_info.
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* . To minimize the data usage by the per-device constraints, the data struct
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* is only allocated at the first call to dev_pm_qos_add_request.
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* is only allocated at the first call to dev_pm_qos_add_request.
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* . The data is later free'd when the device is removed from the system.
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*
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* Notes about locking:
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* . The dev->power.lock lock protects the constraints list
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* (dev->power.constraints) allocation and free, as triggered by the
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* driver core code at device insertion and removal,
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* . A global lock dev_pm_qos_lock protects the constraints list entries
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* from any modification and the notifiers registration and unregistration.
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* . For both locks a spinlock is needed since this code can be called from
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* interrupt context or spinlock protected context.
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* . A global mutex protects the constraints users from the data being
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* allocated and free'd.
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*/
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#include <linux/pm_qos.h>
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#include <linux/spinlock.h>
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#include <linux/slab.h>
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#include <linux/device.h>
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#include <linux/mutex.h>
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#include <linux/export.h>
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#include "power.h"
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static DEFINE_SPINLOCK(dev_pm_qos_lock);
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static DEFINE_MUTEX(dev_pm_qos_mtx);
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static BLOCKING_NOTIFIER_HEAD(dev_pm_notifiers);
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@ -116,19 +110,18 @@ static int apply_constraint(struct dev_pm_qos_request *req,
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* @dev: device to allocate data for
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*
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* Called at the first call to add_request, for constraint data allocation
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* Must be called with the dev_pm_qos_lock lock held
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* Must be called with the dev_pm_qos_mtx mutex held
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*/
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static int dev_pm_qos_constraints_allocate(struct device *dev)
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{
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struct pm_qos_constraints *c;
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struct blocking_notifier_head *n;
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unsigned long flags;
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c = kzalloc(sizeof(*c), GFP_ATOMIC);
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c = kzalloc(sizeof(*c), GFP_KERNEL);
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if (!c)
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return -ENOMEM;
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n = kzalloc(sizeof(*n), GFP_ATOMIC);
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n = kzalloc(sizeof(*n), GFP_KERNEL);
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if (!n) {
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kfree(c);
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return -ENOMEM;
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@ -141,9 +134,9 @@ static int dev_pm_qos_constraints_allocate(struct device *dev)
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c->type = PM_QOS_MIN;
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c->notifiers = n;
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spin_lock_irqsave(&dev->power.lock, flags);
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spin_lock_irq(&dev->power.lock);
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dev->power.constraints = c;
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spin_unlock_irqrestore(&dev->power.lock, flags);
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spin_unlock_irq(&dev->power.lock);
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return 0;
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}
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@ -157,12 +150,10 @@ static int dev_pm_qos_constraints_allocate(struct device *dev)
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*/
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void dev_pm_qos_constraints_init(struct device *dev)
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{
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unsigned long flags;
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spin_lock_irqsave(&dev_pm_qos_lock, flags);
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mutex_lock(&dev_pm_qos_mtx);
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dev->power.constraints = NULL;
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dev->power.power_state = PMSG_ON;
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spin_unlock_irqrestore(&dev_pm_qos_lock, flags);
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mutex_unlock(&dev_pm_qos_mtx);
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}
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/**
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@ -175,7 +166,6 @@ void dev_pm_qos_constraints_destroy(struct device *dev)
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{
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struct dev_pm_qos_request *req, *tmp;
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struct pm_qos_constraints *c;
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unsigned long flags;
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/*
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* If the device's PM QoS resume latency limit has been exposed to user
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@ -183,7 +173,7 @@ void dev_pm_qos_constraints_destroy(struct device *dev)
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*/
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dev_pm_qos_hide_latency_limit(dev);
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spin_lock_irqsave(&dev_pm_qos_lock, flags);
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mutex_lock(&dev_pm_qos_mtx);
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dev->power.power_state = PMSG_INVALID;
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c = dev->power.constraints;
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@ -208,7 +198,7 @@ void dev_pm_qos_constraints_destroy(struct device *dev)
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kfree(c);
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out:
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spin_unlock_irqrestore(&dev_pm_qos_lock, flags);
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mutex_unlock(&dev_pm_qos_mtx);
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}
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/**
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@ -233,7 +223,6 @@ int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
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s32 value)
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{
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int ret = 0;
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unsigned long flags;
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if (!dev || !req) /*guard against callers passing in null */
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return -EINVAL;
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@ -244,7 +233,7 @@ int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
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req->dev = dev;
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spin_lock_irqsave(&dev_pm_qos_lock, flags);
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mutex_lock(&dev_pm_qos_mtx);
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if (!dev->power.constraints) {
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if (dev->power.power_state.event == PM_EVENT_INVALID) {
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@ -266,7 +255,7 @@ int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
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ret = apply_constraint(req, PM_QOS_ADD_REQ, value);
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out:
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spin_unlock_irqrestore(&dev_pm_qos_lock, flags);
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mutex_unlock(&dev_pm_qos_mtx);
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return ret;
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}
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@ -291,7 +280,6 @@ int dev_pm_qos_update_request(struct dev_pm_qos_request *req,
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s32 new_value)
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{
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int ret = 0;
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unsigned long flags;
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if (!req) /*guard against callers passing in null */
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return -EINVAL;
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@ -300,7 +288,7 @@ int dev_pm_qos_update_request(struct dev_pm_qos_request *req,
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"%s() called for unknown object\n", __func__))
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return -EINVAL;
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spin_lock_irqsave(&dev_pm_qos_lock, flags);
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mutex_lock(&dev_pm_qos_mtx);
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if (req->dev->power.constraints) {
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if (new_value != req->node.prio)
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@ -311,7 +299,7 @@ int dev_pm_qos_update_request(struct dev_pm_qos_request *req,
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ret = -ENODEV;
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}
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spin_unlock_irqrestore(&dev_pm_qos_lock, flags);
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mutex_unlock(&dev_pm_qos_mtx);
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return ret;
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}
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EXPORT_SYMBOL_GPL(dev_pm_qos_update_request);
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@ -331,7 +319,6 @@ EXPORT_SYMBOL_GPL(dev_pm_qos_update_request);
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int dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
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{
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int ret = 0;
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unsigned long flags;
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if (!req) /*guard against callers passing in null */
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return -EINVAL;
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@ -340,7 +327,7 @@ int dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
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"%s() called for unknown object\n", __func__))
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return -EINVAL;
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spin_lock_irqsave(&dev_pm_qos_lock, flags);
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mutex_lock(&dev_pm_qos_mtx);
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if (req->dev->power.constraints) {
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ret = apply_constraint(req, PM_QOS_REMOVE_REQ,
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@ -351,7 +338,7 @@ int dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
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ret = -ENODEV;
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}
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spin_unlock_irqrestore(&dev_pm_qos_lock, flags);
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mutex_unlock(&dev_pm_qos_mtx);
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return ret;
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}
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EXPORT_SYMBOL_GPL(dev_pm_qos_remove_request);
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@ -372,9 +359,8 @@ EXPORT_SYMBOL_GPL(dev_pm_qos_remove_request);
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int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier)
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{
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int ret = 0;
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unsigned long flags;
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spin_lock_irqsave(&dev_pm_qos_lock, flags);
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mutex_lock(&dev_pm_qos_mtx);
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if (!dev->power.constraints)
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ret = dev->power.power_state.event != PM_EVENT_INVALID ?
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@ -384,7 +370,7 @@ int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier)
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ret = blocking_notifier_chain_register(
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dev->power.constraints->notifiers, notifier);
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spin_unlock_irqrestore(&dev_pm_qos_lock, flags);
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mutex_unlock(&dev_pm_qos_mtx);
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return ret;
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}
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EXPORT_SYMBOL_GPL(dev_pm_qos_add_notifier);
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@ -403,9 +389,8 @@ int dev_pm_qos_remove_notifier(struct device *dev,
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struct notifier_block *notifier)
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{
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int retval = 0;
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unsigned long flags;
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spin_lock_irqsave(&dev_pm_qos_lock, flags);
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mutex_lock(&dev_pm_qos_mtx);
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/* Silently return if the constraints object is not present. */
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if (dev->power.constraints)
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@ -413,7 +398,7 @@ int dev_pm_qos_remove_notifier(struct device *dev,
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dev->power.constraints->notifiers,
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notifier);
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spin_unlock_irqrestore(&dev_pm_qos_lock, flags);
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mutex_unlock(&dev_pm_qos_mtx);
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return retval;
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}
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EXPORT_SYMBOL_GPL(dev_pm_qos_remove_notifier);
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