/*
 * gpio-aggregator-avm-wrapper.h
 *
 *  Created on: Mar 2, 2021
 *      Author: cmimidis
 */

#ifndef DRIVERS_GPIO_GPIO_AGGREGATOR_AVM_WRAPPER_H_
#define DRIVERS_GPIO_GPIO_AGGREGATOR_AVM_WRAPPER_H_

/*
 * slab.h is needed by the gpio-aggregator and not explicitly included by it.
 * This ist done here.
 */
#include <linux/slab.h>

/*
 * idr_remove
 * idr_remove is expected to return a void pointer to a struct gpio_aggregator.
 * This behavior is introduced with commit d3e709e63e97e5
 * A cherry pick is not easily possible since the idr subsystem is also used by
 * many other modules. So a change here can introduce problems outside the gpio
 * subsystem.
 * That's why the following wrapper is implemented.
 * Note: The next stable kernel after 4.9 (4.14) contain the updated ida_remove
 * function. If the kernel is updated, this wrapper and its references can be
 * removed safely.
**/
static void *idr_remove_wrapper(struct idr *idp, int id)
{
	void *data = idr_find(idp, id);

	/*
	 * first check data as if idr_find wouldn't succeed idr_remove wouldn't
	 * succeed either with the given id! idr_find only fails with an invalid
	 * id or NULL given.
	 **/
	if (!data)
		return NULL;
	idr_remove(idp, id);
	return data;
}

#endif /* DRIVERS_GPIO_GPIO_AGGREGATOR_AVM_WRAPPER_H_ */