PM / QoS: Remove device PM QoS sysfs attributes at the right place
Device PM QoS sysfs attributes, if present during device removal,
are removed from within device_pm_remove(), which is too late,
since dpm_sysfs_remove() has already removed the whole attribute
group they belonged to. However, moving the removal of those
attributes to dpm_sysfs_remove() alone is not sufficient, because
in theory they still can be re-added right after being removed by it
(the device's driver is still bound to it at that point).
For this reason, move the entire desctruction of device PM QoS
constraints to dpm_sysfs_remove() and make it prevent any new
constraints from being added after it has run. Also, move the
initialization of the power.qos field in struct device to
device_pm_init_common() and drop the no longer needed
dev_pm_qos_constraints_init().
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index 2159d62..5f74587e 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -41,6 +41,7 @@
#include <linux/mutex.h>
#include <linux/export.h>
#include <linux/pm_runtime.h>
+#include <linux/err.h>
#include "power.h"
@@ -61,7 +62,7 @@
struct pm_qos_flags *pqf;
s32 val;
- if (!qos)
+ if (IS_ERR_OR_NULL(qos))
return PM_QOS_FLAGS_UNDEFINED;
pqf = &qos->flags;
@@ -101,7 +102,8 @@
*/
s32 __dev_pm_qos_read_value(struct device *dev)
{
- return dev->power.qos ? pm_qos_read_value(&dev->power.qos->latency) : 0;
+ return IS_ERR_OR_NULL(dev->power.qos) ?
+ 0 : pm_qos_read_value(&dev->power.qos->latency);
}
/**
@@ -198,20 +200,8 @@
return 0;
}
-/**
- * dev_pm_qos_constraints_init - Initalize device's PM QoS constraints pointer.
- * @dev: target device
- *
- * Called from the device PM subsystem during device insertion under
- * device_pm_lock().
- */
-void dev_pm_qos_constraints_init(struct device *dev)
-{
- mutex_lock(&dev_pm_qos_mtx);
- dev->power.qos = NULL;
- dev->power.power_state = PMSG_ON;
- mutex_unlock(&dev_pm_qos_mtx);
-}
+static void __dev_pm_qos_hide_latency_limit(struct device *dev);
+static void __dev_pm_qos_hide_flags(struct device *dev);
/**
* dev_pm_qos_constraints_destroy
@@ -226,16 +216,15 @@
struct pm_qos_constraints *c;
struct pm_qos_flags *f;
+ mutex_lock(&dev_pm_qos_mtx);
+
/*
* If the device's PM QoS resume latency limit or PM QoS flags have been
* exposed to user space, they have to be hidden at this point.
*/
- dev_pm_qos_hide_latency_limit(dev);
- dev_pm_qos_hide_flags(dev);
+ __dev_pm_qos_hide_latency_limit(dev);
+ __dev_pm_qos_hide_flags(dev);
- mutex_lock(&dev_pm_qos_mtx);
-
- dev->power.power_state = PMSG_INVALID;
qos = dev->power.qos;
if (!qos)
goto out;
@@ -257,7 +246,7 @@
}
spin_lock_irq(&dev->power.lock);
- dev->power.qos = NULL;
+ dev->power.qos = ERR_PTR(-ENODEV);
spin_unlock_irq(&dev->power.lock);
kfree(c->notifiers);
@@ -301,32 +290,19 @@
"%s() called for already added request\n", __func__))
return -EINVAL;
- req->dev = dev;
-
mutex_lock(&dev_pm_qos_mtx);
- if (!dev->power.qos) {
- if (dev->power.power_state.event == PM_EVENT_INVALID) {
- /* The device has been removed from the system. */
- req->dev = NULL;
- ret = -ENODEV;
- goto out;
- } else {
- /*
- * Allocate the constraints data on the first call to
- * add_request, i.e. only if the data is not already
- * allocated and if the device has not been removed.
- */
- ret = dev_pm_qos_constraints_allocate(dev);
- }
- }
+ if (IS_ERR(dev->power.qos))
+ ret = -ENODEV;
+ else if (!dev->power.qos)
+ ret = dev_pm_qos_constraints_allocate(dev);
if (!ret) {
+ req->dev = dev;
req->type = type;
ret = apply_constraint(req, PM_QOS_ADD_REQ, value);
}
- out:
mutex_unlock(&dev_pm_qos_mtx);
return ret;
@@ -351,7 +327,7 @@
"%s() called for unknown object\n", __func__))
return -EINVAL;
- if (!req->dev->power.qos)
+ if (IS_ERR_OR_NULL(req->dev->power.qos))
return -ENODEV;
switch(req->type) {
@@ -402,7 +378,7 @@
static int __dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
{
- int ret = 0;
+ int ret;
if (!req) /*guard against callers passing in null */
return -EINVAL;
@@ -411,13 +387,11 @@
"%s() called for unknown object\n", __func__))
return -EINVAL;
- if (req->dev->power.qos) {
- ret = apply_constraint(req, PM_QOS_REMOVE_REQ,
- PM_QOS_DEFAULT_VALUE);
- memset(req, 0, sizeof(*req));
- } else {
- ret = -ENODEV;
- }
+ if (IS_ERR_OR_NULL(req->dev->power.qos))
+ return -ENODEV;
+
+ ret = apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
+ memset(req, 0, sizeof(*req));
return ret;
}
@@ -466,9 +440,10 @@
mutex_lock(&dev_pm_qos_mtx);
- if (!dev->power.qos)
- ret = dev->power.power_state.event != PM_EVENT_INVALID ?
- dev_pm_qos_constraints_allocate(dev) : -ENODEV;
+ if (IS_ERR(dev->power.qos))
+ ret = -ENODEV;
+ else if (!dev->power.qos)
+ ret = dev_pm_qos_constraints_allocate(dev);
if (!ret)
ret = blocking_notifier_chain_register(
@@ -497,7 +472,7 @@
mutex_lock(&dev_pm_qos_mtx);
/* Silently return if the constraints object is not present. */
- if (dev->power.qos)
+ if (!IS_ERR_OR_NULL(dev->power.qos))
retval = blocking_notifier_chain_unregister(
dev->power.qos->latency.notifiers,
notifier);
@@ -608,7 +583,7 @@
mutex_lock(&dev_pm_qos_mtx);
- if (!dev->power.qos)
+ if (IS_ERR_OR_NULL(dev->power.qos))
ret = -ENODEV;
else if (dev->power.qos->latency_req)
ret = -EEXIST;
@@ -630,6 +605,14 @@
}
EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_limit);
+static void __dev_pm_qos_hide_latency_limit(struct device *dev)
+{
+ if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->latency_req) {
+ pm_qos_sysfs_remove_latency(dev);
+ __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY);
+ }
+}
+
/**
* dev_pm_qos_hide_latency_limit - Hide PM QoS latency limit from user space.
* @dev: Device whose PM QoS latency limit is to be hidden from user space.
@@ -637,12 +620,7 @@
void dev_pm_qos_hide_latency_limit(struct device *dev)
{
mutex_lock(&dev_pm_qos_mtx);
-
- if (dev->power.qos && dev->power.qos->latency_req) {
- pm_qos_sysfs_remove_latency(dev);
- __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY);
- }
-
+ __dev_pm_qos_hide_latency_limit(dev);
mutex_unlock(&dev_pm_qos_mtx);
}
EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_limit);
@@ -673,7 +651,7 @@
pm_runtime_get_sync(dev);
mutex_lock(&dev_pm_qos_mtx);
- if (!dev->power.qos)
+ if (IS_ERR_OR_NULL(dev->power.qos))
ret = -ENODEV;
else if (dev->power.qos->flags_req)
ret = -EEXIST;
@@ -696,6 +674,14 @@
}
EXPORT_SYMBOL_GPL(dev_pm_qos_expose_flags);
+static void __dev_pm_qos_hide_flags(struct device *dev)
+{
+ if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->flags_req) {
+ pm_qos_sysfs_remove_flags(dev);
+ __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_FLAGS);
+ }
+}
+
/**
* dev_pm_qos_hide_flags - Hide PM QoS flags of a device from user space.
* @dev: Device whose PM QoS flags are to be hidden from user space.
@@ -704,12 +690,7 @@
{
pm_runtime_get_sync(dev);
mutex_lock(&dev_pm_qos_mtx);
-
- if (dev->power.qos && dev->power.qos->flags_req) {
- pm_qos_sysfs_remove_flags(dev);
- __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_FLAGS);
- }
-
+ __dev_pm_qos_hide_flags(dev);
mutex_unlock(&dev_pm_qos_mtx);
pm_runtime_put(dev);
}
@@ -729,7 +710,7 @@
pm_runtime_get_sync(dev);
mutex_lock(&dev_pm_qos_mtx);
- if (!dev->power.qos || !dev->power.qos->flags_req) {
+ if (IS_ERR_OR_NULL(dev->power.qos) || !dev->power.qos->flags_req) {
ret = -EINVAL;
goto out;
}
@@ -747,4 +728,7 @@
pm_runtime_put(dev);
return ret;
}
+#else /* !CONFIG_PM_RUNTIME */
+static void __dev_pm_qos_hide_latency_limit(struct device *dev) {}
+static void __dev_pm_qos_hide_flags(struct device *dev) {}
#endif /* CONFIG_PM_RUNTIME */