147 lines
3.3 KiB
C
147 lines
3.3 KiB
C
/*
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* net/9p/util.c
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*
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* This file contains some helper functions
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*
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* Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
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* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
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* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to:
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* Free Software Foundation
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* 51 Franklin Street, Fifth Floor
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* Boston, MA 02111-1301 USA
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*
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*/
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/sched.h>
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#include <linux/parser.h>
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#include <linux/idr.h>
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#include <linux/slab.h>
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#include <net/9p/9p.h>
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/**
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* struct p9_idpool - per-connection accounting for tag idpool
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* @lock: protects the pool
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* @pool: idr to allocate tag id from
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*
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*/
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struct p9_idpool {
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spinlock_t lock;
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struct idr pool;
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};
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/**
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* p9_idpool_create - create a new per-connection id pool
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*
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*/
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struct p9_idpool *p9_idpool_create(void)
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{
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struct p9_idpool *p;
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p = kmalloc(sizeof(struct p9_idpool), GFP_KERNEL);
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if (!p)
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return ERR_PTR(-ENOMEM);
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spin_lock_init(&p->lock);
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idr_init(&p->pool);
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return p;
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}
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EXPORT_SYMBOL(p9_idpool_create);
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/**
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* p9_idpool_destroy - create a new per-connection id pool
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* @p: idpool to destroy
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*/
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void p9_idpool_destroy(struct p9_idpool *p)
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{
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idr_destroy(&p->pool);
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kfree(p);
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}
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EXPORT_SYMBOL(p9_idpool_destroy);
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/**
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* p9_idpool_get - allocate numeric id from pool
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* @p: pool to allocate from
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*
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* Bugs: This seems to be an awful generic function, should it be in idr.c with
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* the lock included in struct idr?
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*/
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int p9_idpool_get(struct p9_idpool *p)
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{
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int i = 0;
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int error;
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unsigned long flags;
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retry:
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if (idr_pre_get(&p->pool, GFP_NOFS) == 0)
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return -1;
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spin_lock_irqsave(&p->lock, flags);
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/* no need to store exactly p, we just need something non-null */
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error = idr_get_new(&p->pool, p, &i);
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spin_unlock_irqrestore(&p->lock, flags);
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if (error == -EAGAIN)
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goto retry;
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else if (error)
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return -1;
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p9_debug(P9_DEBUG_MUX, " id %d pool %p\n", i, p);
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return i;
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}
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EXPORT_SYMBOL(p9_idpool_get);
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/**
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* p9_idpool_put - release numeric id from pool
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* @id: numeric id which is being released
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* @p: pool to release id into
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*
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* Bugs: This seems to be an awful generic function, should it be in idr.c with
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* the lock included in struct idr?
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*/
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void p9_idpool_put(int id, struct p9_idpool *p)
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{
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unsigned long flags;
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p9_debug(P9_DEBUG_MUX, " id %d pool %p\n", id, p);
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spin_lock_irqsave(&p->lock, flags);
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idr_remove(&p->pool, id);
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spin_unlock_irqrestore(&p->lock, flags);
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}
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EXPORT_SYMBOL(p9_idpool_put);
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/**
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* p9_idpool_check - check if the specified id is available
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* @id: id to check
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* @p: pool to check
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*/
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int p9_idpool_check(int id, struct p9_idpool *p)
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{
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return idr_find(&p->pool, id) != NULL;
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}
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EXPORT_SYMBOL(p9_idpool_check);
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