Commit f1725160 authored by Danilo Krummrich's avatar Danilo Krummrich Committed by Greg Kroah-Hartman
Browse files

devres: add devm_remove_action_nowarn() 



devm_remove_action() warns if the action to remove does not exist
(anymore).

The Rust devres abstraction, however, has a use-case to call
devm_remove_action() at a point where it can't be guaranteed that the
corresponding action hasn't been released yet.

In particular, an instance of `Devres<T>` may be dropped after the
action has been released. So far, `Devres<T>` worked around this by
keeping the inner type alive.

Hence, add devm_remove_action_nowarn(), which returns an error code if
the action has been removed already.

A subsequent patch uses devm_remove_action_nowarn() to remove the action
when `Devres<T>` is dropped.

Signed-off-by: default avatarDanilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250107122609.8135-1-dakr@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 827ed8b1

drivers/base/devres.c

+18 −5
Original line number Diff line number Diff line
@@ -750,25 +750,38 @@ int __devm_add_action(struct device *dev, void (*action)(void *), void *data, co 
EXPORT_SYMBOL_GPL(__devm_add_action);



/**

 * devm_remove_action() - removes previously added custom action

 * devm_remove_action_nowarn() - 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.

 *

 * In contrast to devm_remove_action(), this function does not WARN() if no

 * entry could have been found.

 *

 * This should only be used if the action is contained in an object with

 * independent lifetime management, e.g. the Devres rust abstraction.

 *

 * Causing the warning from regular driver code most likely indicates an abuse

 * of the devres API.

 *

 * Returns: 0 on success, -ENOENT if no entry could have been found.

 */

void devm_remove_action(struct device *dev, void (*action)(void *), void *data)

int devm_remove_action_nowarn(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));

	return devres_destroy(dev, devm_action_release, devm_action_match,

			      &devres);

}

EXPORT_SYMBOL_GPL(devm_remove_action);

EXPORT_SYMBOL_GPL(devm_remove_action_nowarn);



/**

 * devm_release_action() - release previously added custom action

include/linux/device.h

+17 −1
Original line number Diff line number Diff line
@@ -399,7 +399,23 @@ void __iomem *devm_of_iomap(struct device *dev, 
#endif



/* allows to add/remove a custom action to devres stack */

void devm_remove_action(struct device *dev, void (*action)(void *), void *data);

int devm_remove_action_nowarn(struct device *dev, void (*action)(void *), void *data);



/**

 * 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.

 */

static inline

void devm_remove_action(struct device *dev, void (*action)(void *), void *data)

{

	WARN_ON(devm_remove_action_nowarn(dev, action, data));

}



void devm_release_action(struct device *dev, void (*action)(void *), void *data);



int __devm_add_action(struct device *dev, void (*action)(void *), void *data, const char *name);