dea7bbb603
When booting from v9fs, down_interruptible in p9_idpool_get() triggered a BUG as it was being called with IRQs disabled. A spinlock seems like the right thing to be using since the idr functions go out of their way not to sleep. This patch eliminates the BUG by converting the semaphore to a spinlock. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Acked-by: Eric Van Hensbergen <ericvh@gmail.com>
121 lines
2.8 KiB
C
121 lines
2.8 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 <net/9p/9p.h>
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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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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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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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* XXX - 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 int flags;
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retry:
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if (idr_pre_get(&p->pool, GFP_KERNEL) == 0)
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return 0;
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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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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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* @p - pool to allocate from
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*
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* XXX - 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 int flags;
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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
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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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