// SPDX-License-Identifier: GPL-2.0-only
/*
 * 2002-10-18  written by Jim Houston jim.houston@ccur.com
 *	Copyright (C) 2002 by Concurrent Computer Corporation
 *	Distributed under the GNU GPL license version 2.
 *
 * Modified by George Anzinger to reuse immediately and to use
 * find bit instructions.  Also removed _irq on spinlocks.
 *
 * Modified by Nadia Derbey to make it RCU safe.
 *
 * Small id to pointer translation service.
 *
 * It uses a radix tree like structure as a sparse array indexed
 * by the id to obtain the pointer.  The bitmap makes allocating
 * a new id quick.
 *
 * You call it to allocate an id (an int) an associate with that id a
 * pointer or what ever, we treat it as a (void *).  You can pass this
 * id to a user for him to pass back at a later time.  You then pass
 * that id to this code and it returns your pointer.
 */

#include "linux_export.h"

#include <linux_err.h>

#include <idr.h>


void *idr_find_slowpath(struct idr *idp, int id)
{
#ifdef MAC80211_TODO
	int n;
	struct idr_layer *p;

	if (id < 0)
		return NULL;

	p = rcu_dereference_raw(idp->top);
	if (!p)
		return NULL;
	n = (p->layer+1) * IDR_BITS;

	if (id > idr_max(p->layer + 1))
		return NULL;
	BUG_ON(n == 0);

	while (n > 0 && p) {
		n -= IDR_BITS;
		BUG_ON(n != p->layer*IDR_BITS);
		p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]);
	}
	return((void *)p);
#else
	(void)idp;
	(void)id;
	return NULL;
#endif /* MAC80211_TODO */
}
EXPORT_SYMBOL(idr_find_slowpath);