From d6b0c58048d2c8c6f4955c37f670125b2792cd14 Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Sat, 23 Feb 2013 13:11:14 -0800 Subject: devres: allow adding custom actions to the stack 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 Acked-by: Greg Kroah-Hartman Signed-off-by: Dmitry Torokhov --- drivers/base/devres.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) (limited to 'drivers/base/devres.c') diff --git a/drivers/base/devres.c b/drivers/base/devres.c index 8731979d668a..724957a13d48 100644 --- a/drivers/base/devres.c +++ b/drivers/base/devres.c @@ -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 */ -- cgit v1.2.1