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devres: allow adding custom actions to the stack

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Sometimes drivers need to execute one-off actions in their error handling
or device teardown paths. An example would be toggling a GPIO line to
reset the controlled device into predefined state.

To allow performing such actions when using managed resources let's allow
adding them to stack/group of devres resources.

Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Dmitry Torokhov 2013-02-23 13:11:14 -08:00
parent 7241443f67
commit d6b0c58048
2 changed files with 78 additions and 0 deletions
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74
drivers/base/devres.c
View file

@ -670,6 +670,80 @@ int devres_release_group(struct device *dev, void *id)
}
EXPORT_SYMBOL_GPL(devres_release_group);
/*
* Custom devres actions allow inserting a simple function call
* into the teadown sequence.
*/
struct action_devres {
void *data;
void (*action)(void *);
};
static int devm_action_match(struct device *dev, void *res, void *p)
{
struct action_devres *devres = res;
struct action_devres *target = p;
return devres->action == target->action &&
devres->data == target->data;
}
static void devm_action_release(struct device *dev, void *res)
{
struct action_devres *devres = res;
devres->action(devres->data);
}
/**
* devm_add_action() - add a custom action to list of managed resources
* @dev: Device that owns the action
* @action: Function that should be called
* @data: Pointer to data passed to @action implementation
*
* This adds a custom action to the list of managed resources so that
* it gets executed as part of standard resource unwinding.
*/
int devm_add_action(struct device *dev, void (*action)(void *), void *data)
{
struct action_devres *devres;
devres = devres_alloc(devm_action_release,
sizeof(struct action_devres), GFP_KERNEL);
if (!devres)
return -ENOMEM;
devres->data = data;
devres->action = action;
devres_add(dev, devres);
return 0;
}
EXPORT_SYMBOL_GPL(devm_add_action);
/**
* devm_remove_action() - removes previously added custom action
* @dev: Device that owns the action
* @action: Function implementing the action
* @data: Pointer to data passed to @action implementation
*
* Removes instance of @action previously added by devm_add_action().
* Both action and data should match one of the existing entries.
*/
void devm_remove_action(struct device *dev, void (*action)(void *), void *data)
{
struct action_devres devres = {
.data = data,
.action = action,
};
WARN_ON(devres_destroy(dev, devm_action_release, devm_action_match,
&devres));
}
EXPORT_SYMBOL_GPL(devm_remove_action);
/*
* Managed kzalloc/kfree
*/

4
include/linux/device.h
View file

@ -567,6 +567,10 @@ extern void devm_kfree(struct device *dev, void *p);
void __iomem *devm_request_and_ioremap(struct device *dev,
struct resource *res);
/* allows to add/remove a custom action to devres stack */
int devm_add_action(struct device *dev, void (*action)(void *), void *data);
void devm_remove_action(struct device *dev, void (*action)(void *), void *data);
struct device_dma_parameters {
/*
* a low level driver may set these to teach IOMMU code about