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/*
* Copyright 2012 Hauke Mehrtens <hauke@hauke-m.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Backport functionality introduced in Linux 3.1.
*/
#include <linux/idr.h>
#include <linux/cpufreq.h>
static DEFINE_SPINLOCK(compat_simple_ida_lock);
/**
* ida_simple_get - get a new id.
* @ida: the (initialized) ida.
* @start: the minimum id (inclusive, < 0x8000000)
* @end: the maximum id (exclusive, < 0x8000000 or 0)
* @gfp_mask: memory allocation flags
*
* Allocates an id in the range start <= id < end, or returns -ENOSPC.
* On memory allocation failure, returns -ENOMEM.
*
* Use ida_simple_remove() to get rid of an id.
*/
int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end,
gfp_t gfp_mask)
{
int ret, id;
unsigned int max;
unsigned long flags;
BUG_ON((int)start < 0);
BUG_ON((int)end < 0);
if (end == 0)
max = 0x80000000;
else {
BUG_ON(end < start);
max = end - 1;
}
again:
if (!ida_pre_get(ida, gfp_mask))
return -ENOMEM;
spin_lock_irqsave(&compat_simple_ida_lock, flags);
ret = ida_get_new_above(ida, start, &id);
if (!ret) {
if (id > max) {
ida_remove(ida, id);
ret = -ENOSPC;
} else {
ret = id;
}
}
spin_unlock_irqrestore(&compat_simple_ida_lock, flags);
if (unlikely(ret == -EAGAIN))
goto again;
return ret;
}
EXPORT_SYMBOL_GPL(ida_simple_get);
/**
* ida_simple_remove - remove an allocated id.
* @ida: the (initialized) ida.
* @id: the id returned by ida_simple_get.
*/
void ida_simple_remove(struct ida *ida, unsigned int id)
{
unsigned long flags;
BUG_ON((int)id < 0);
spin_lock_irqsave(&compat_simple_ida_lock, flags);
ida_remove(ida, id);
spin_unlock_irqrestore(&compat_simple_ida_lock, flags);
}
EXPORT_SYMBOL_GPL(ida_simple_remove);
/* source lib/idr.c */
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