We introduce new atomic_notifiers and only call the (legacy) blocking
notifiers if there are any registered. A might_sleep() tries to
fence off all misuse.
This should make it possible to call update_request from interrupt-context
as long as only atomic notifiers are registered.
Signed-off-by: Florian Mickler <florian@xxxxxxxxxxx>
---
include/linux/pm_qos_params.h | 3 +
kernel/pm_qos_params.c | 114 ++++++++++++++++++++++++++++++++--------
2 files changed, 94 insertions(+), 23 deletions(-)
diff --git a/include/linux/pm_qos_params.h b/include/linux/pm_qos_params.h
index 8ba440e..60ed542 100644
--- a/include/linux/pm_qos_params.h
+++ b/include/linux/pm_qos_params.h
@@ -22,6 +22,9 @@ void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req);
int pm_qos_request(int pm_qos_class);
+
int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier);
int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier);
+int pm_qos_add_notifier_nonblocking(int pm_qos_class, struct notifier_block *notifier);
+int pm_qos_remove_notifier_nonblocking(int pm_qos_class, struct notifier_block *notifier);
diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c
index f42d3f7..0a67997 100644
--- a/kernel/pm_qos_params.c
+++ b/kernel/pm_qos_params.c
@@ -63,7 +63,8 @@ static s32 min_compare(s32 v1, s32 v2);
struct pm_qos_object {
struct pm_qos_request_list requests;
- struct blocking_notifier_head *notifiers;
+ struct atomic_notifier_head *notifiers;
+ struct blocking_notifier_head *blocking_notifiers;
struct miscdevice pm_qos_power_miscdev;
char *name;
s32 default_value;
@@ -72,20 +73,24 @@ struct pm_qos_object {
};
static struct pm_qos_object null_pm_qos;
-static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
+static ATOMIC_NOTIFIER_HEAD(cpu_dma_lat_notifier);
+static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_blocking_notifier);
static struct pm_qos_object cpu_dma_pm_qos = {
.requests = {LIST_HEAD_INIT(cpu_dma_pm_qos.requests.list)},
.notifiers = &cpu_dma_lat_notifier,
+ .blocking_notifiers = &cpu_dma_lat_blocking_notifier,
.name = "cpu_dma_latency",
.default_value = 2000 * USEC_PER_SEC,
.target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
.comparitor = min_compare
};
-static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
+static ATOMIC_NOTIFIER_HEAD(network_lat_notifier);
+static BLOCKING_NOTIFIER_HEAD(network_lat_blocking_notifier);
static struct pm_qos_object network_lat_pm_qos = {
.requests = {LIST_HEAD_INIT(network_lat_pm_qos.requests.list)},
.notifiers = &network_lat_notifier,
+ .blocking_notifiers = &network_lat_blocking_notifier,
.name = "network_latency",
.default_value = 2000 * USEC_PER_SEC,
.target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
@@ -93,17 +98,18 @@ static struct pm_qos_object network_lat_pm_qos = {
};
-static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
+static ATOMIC_NOTIFIER_HEAD(network_throughput_notifier);
+static BLOCKING_NOTIFIER_HEAD(network_throughput_blocking_notifier);
static struct pm_qos_object network_throughput_pm_qos = {
.requests = {LIST_HEAD_INIT(network_throughput_pm_qos.requests.list)},
.notifiers = &network_throughput_notifier,
+ .blocking_notifiers = &network_throughput_blocking_notifier,
.name = "network_throughput",
.default_value = 0,
.target_value = ATOMIC_INIT(0),
.comparitor = max_compare
};
-
static struct pm_qos_object *pm_qos_array[] = {
&null_pm_qos,
&cpu_dma_pm_qos,
@@ -135,35 +141,45 @@ static s32 min_compare(s32 v1, s32 v2)
return min(v1, v2);
}
+/* these notifiers may not be cool to call from interrupt context... */
+static void blocking_update_notify(struct pm_qos_object *obj)
+{
+ s32 extreme_value;
+
+ might_sleep();
+
+ extreme_value = atomic_read(&obj->target_value);
+ blocking_notifier_call_chain(obj->blocking_notifiers,
+ (unsigned long) extreme_value, NULL);
+}
static void update_target(int pm_qos_class)
{
s32 extreme_value;
+ struct pm_qos_object *obj = pm_qos_array[pm_qos_class];
struct pm_qos_request_list *node;
unsigned long flags;
int call_notifier = 0;
spin_lock_irqsave(&pm_qos_lock, flags);
- extreme_value = pm_qos_array[pm_qos_class]->default_value;
- list_for_each_entry(node,
- &pm_qos_array[pm_qos_class]->requests.list, list) {
- extreme_value = pm_qos_array[pm_qos_class]->comparitor(
- extreme_value, node->value);
+ extreme_value = obj->default_value;
+ list_for_each_entry(node, &obj->requests.list, list) {
+ extreme_value = obj->comparitor(extreme_value, node->value);
}
- if (atomic_read(&pm_qos_array[pm_qos_class]->target_value) !=
- extreme_value) {
+ if (atomic_read(&obj->target_value) != extreme_value) {
call_notifier = 1;
- atomic_set(&pm_qos_array[pm_qos_class]->target_value,
- extreme_value);
+ atomic_set(&obj->target_value, extreme_value);
pr_debug(KERN_ERR "new target for qos %d is %d\n", pm_qos_class,
- atomic_read(&pm_qos_array[pm_qos_class]->target_value));
+ atomic_read(&obj->target_value));
}
spin_unlock_irqrestore(&pm_qos_lock, flags);
- if (call_notifier)
- blocking_notifier_call_chain(
- pm_qos_array[pm_qos_class]->notifiers,
- (unsigned long) extreme_value, NULL);
+ if (call_notifier) {
+ atomic_notifier_call_chain(obj->notifiers,
+ (unsigned long) extreme_value, NULL);
+ if (obj->blocking_notifiers->head != NULL)
+ blocking_update_notify(obj);
+ }
}
static int register_pm_qos_misc(struct pm_qos_object *qos)
@@ -272,6 +288,7 @@ EXPORT_SYMBOL_GPL(pm_qos_update_request);
/**
* pm_qos_remove_request - modifies an existing qos request
+ *
* @pm_qos_req: handle to request list element
*
* Will remove pm qos request from the list of requests and
@@ -297,11 +314,39 @@ void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req)
EXPORT_SYMBOL_GPL(pm_qos_remove_request);
/**
+ * pm_qos_add_notifier_nonblocking - sets notification entry for changes to target value
+ *
+ * Code executed by the notifier block may not sleep!
+ *
+ * @pm_qos_class: identifies which qos target changes should be notified.
+ * @notifier: notifier block managed by caller.
+ *
+ * Will register the notifier into a notification chain that gets called
+ * upon changes to the pm_qos_class target value.
+ */
+int pm_qos_add_notifier_nonblocking(int pm_qos_class, struct notifier_block *notifier)
+{
+ int retval;
+
+ retval = atomic_notifier_chain_register(
+ pm_qos_array[pm_qos_class]->notifiers, notifier);
+
+ return retval;
+}
+EXPORT_SYMBOL_GPL(pm_qos_add_notifier_nonblocking);
+
+
+/**
* pm_qos_add_notifier - sets notification entry for changes to target value
+ *
+ * Notifiers added with this function are executed in process context.
+ * They may also be scheduled for later execution if pm_qos_update_request is
+ * called from interrupt context.
+ *
* @pm_qos_class: identifies which qos target changes should be notified.
* @notifier: notifier block managed by caller.
*
- * will register the notifier into a notification chain that gets called
+ * Will register the notifier into a notification chain that gets called
* upon changes to the pm_qos_class target value.
*/
int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
@@ -309,18 +354,40 @@ int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
int retval;
retval = blocking_notifier_chain_register(
- pm_qos_array[pm_qos_class]->notifiers, notifier);
+ pm_qos_array[pm_qos_class]->blocking_notifiers, notifier);
return retval;
}
EXPORT_SYMBOL_GPL(pm_qos_add_notifier);
/**
+ * pm_qos_remove_notifier_nonblocking - deletes notification entry from the
+ * nonblocking-notifier-chain.
+ *
+ * @pm_qos_class: identifies which qos target changes are notified.
+ * @notifier: notifier block to be removed.
+ *
+ * Will remove the notifier from the notification chain that gets called
+ * upon changes to the pm_qos_class target value.
+ */
+int pm_qos_remove_notifier_nonblocking(int pm_qos_class, struct notifier_block *notifier)
+{
+ int retval;
+
+ retval = atomic_notifier_chain_unregister(
+ pm_qos_array[pm_qos_class]->notifiers, notifier);
+
+ return retval;
+}
+EXPORT_SYMBOL_GPL(pm_qos_remove_notifier_nonblocking);
+
+/**
* pm_qos_remove_notifier - deletes notification entry from chain.
+ *
* @pm_qos_class: identifies which qos target changes are notified.
* @notifier: notifier block to be removed.
*
- * will remove the notifier from the notification chain that gets called
+ * Will remove the notifier from the notification chain that gets called
* upon changes to the pm_qos_class target value.
*/
int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
@@ -328,7 +395,7 @@ int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
int retval;
retval = blocking_notifier_chain_unregister(
- pm_qos_array[pm_qos_class]->notifiers, notifier);
+ pm_qos_array[pm_qos_class]->blocking_notifiers, notifier);
return retval;
}
@@ -381,6 +448,7 @@ static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
} else
return -EINVAL;
+
pm_qos_req = (struct pm_qos_request_list *)filp->private_data;
pm_qos_update_request(pm_qos_req, value);
--
1.7.1
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