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/*
* net/9p/util.c
*
* This file contains some helper functions
*
* Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to:
* Free Software Foundation
* 51 Franklin Street, Fifth Floor
* Boston, MA 02111-1301 USA
*
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/parser.h>
#include <linux/idr.h>
#include <linux/slab.h>
#include <net/9p/9p.h>
/**
* struct p9_idpool - per-connection accounting for tag idpool
* @lock: protects the pool
* @pool: idr to allocate tag id from
*
*/
struct p9_idpool {
spinlock_t lock;
struct idr pool;
};
/**
* p9_idpool_create - create a new per-connection id pool
*
*/
struct p9_idpool *p9_idpool_create(void)
{
struct p9_idpool *p;
p = kmalloc(sizeof(struct p9_idpool), GFP_KERNEL);
if (!p)
return ERR_PTR(-ENOMEM);
spin_lock_init(&p->lock);
idr_init(&p->pool);
return p;
}
EXPORT_SYMBOL(p9_idpool_create);
/**
* p9_idpool_destroy - create a new per-connection id pool
* @p: idpool to destroy
*/
void p9_idpool_destroy(struct p9_idpool *p)
{
idr_destroy(&p->pool);
kfree(p);
}
EXPORT_SYMBOL(p9_idpool_destroy);
/**
* p9_idpool_get - allocate numeric id from pool
* @p: pool to allocate from
*
* Bugs: This seems to be an awful generic function, should it be in idr.c with
* the lock included in struct idr?
*/
int p9_idpool_get(struct p9_idpool *p)
{
int i = 0;
int error;
unsigned long flags;
retry:
if (idr_pre_get(&p->pool, GFP_NOFS) == 0)
return -1;
spin_lock_irqsave(&p->lock, flags);
/* no need to store exactly p, we just need something non-null */
error = idr_get_new(&p->pool, p, &i);
spin_unlock_irqrestore(&p->lock, flags);
if (error == -EAGAIN)
goto retry;
else if (error)
return -1;
P9_DPRINTK(P9_DEBUG_MUX, " id %d pool %p\n", i, p);
return i;
}
EXPORT_SYMBOL(p9_idpool_get);
/**
* p9_idpool_put - release numeric id from pool
* @id: numeric id which is being released
* @p: pool to release id into
*
* Bugs: This seems to be an awful generic function, should it be in idr.c with
* the lock included in struct idr?
*/
void p9_idpool_put(int id, struct p9_idpool *p)
{
unsigned long flags;
P9_DPRINTK(P9_DEBUG_MUX, " id %d pool %p\n", id, p);
spin_lock_irqsave(&p->lock, flags);
idr_remove(&p->pool, id);
spin_unlock_irqrestore(&p->lock, flags);
}
EXPORT_SYMBOL(p9_idpool_put);
/**
* p9_idpool_check - check if the specified id is available
* @id: id to check
* @p: pool to check
*/
int p9_idpool_check(int id, struct p9_idpool *p)
{
return idr_find(&p->pool, id) != NULL;
}
EXPORT_SYMBOL(p9_idpool_check);
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