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. Signed-off-by: Dmitry Torokhov <[email protected]> --- drivers/base/devres.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/device.h | 4 +++ 2 files changed, 78 insertions(+) diff --git a/drivers/base/devres.c b/drivers/base/devres.c index 6683906..507379e 100644 --- a/drivers/base/devres.c +++ b/drivers/base/devres.c @@ -671,6 +671,80 @@ 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 */ static void devm_kzalloc_release(struct device *dev, void *res) diff --git a/include/linux/device.h b/include/linux/device.h index 2fbf088..ba7c802 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -578,6 +578,10 @@ 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 -- 1.7.11.7 -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
