forked from Minki/linux
72029fe85d
9p trans modules aren't refcounted nor were they unregistered properly. Fix it. * Add 9p_trans_module->owner and reference the module on each trans instance creation and put it on destruction. * Protect v9fs_trans_list with a spinlock. This isn't strictly necessary as the list is manipulated only during module loading / unloading but it's a good idea to make the API safe. * Unregister trans modules when the corresponding module is being unloaded. * While at it, kill unnecessary EXPORT_SYMBOL on p9_trans_fd_init(). Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
174 lines
3.8 KiB
C
174 lines
3.8 KiB
C
/*
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* net/9p/9p.c
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*
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* 9P entry point
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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/moduleparam.h>
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#include <net/9p/9p.h>
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#include <linux/fs.h>
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#include <linux/parser.h>
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#include <net/9p/transport.h>
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#include <linux/list.h>
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#include <linux/spinlock.h>
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#ifdef CONFIG_NET_9P_DEBUG
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unsigned int p9_debug_level = 0; /* feature-rific global debug level */
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EXPORT_SYMBOL(p9_debug_level);
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module_param_named(debug, p9_debug_level, uint, 0);
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MODULE_PARM_DESC(debug, "9P debugging level");
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#endif
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/*
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* Dynamic Transport Registration Routines
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*
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*/
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static DEFINE_SPINLOCK(v9fs_trans_lock);
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static LIST_HEAD(v9fs_trans_list);
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/**
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* v9fs_register_trans - register a new transport with 9p
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* @m: structure describing the transport module and entry points
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*
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*/
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void v9fs_register_trans(struct p9_trans_module *m)
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{
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spin_lock(&v9fs_trans_lock);
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list_add_tail(&m->list, &v9fs_trans_list);
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spin_unlock(&v9fs_trans_lock);
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}
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EXPORT_SYMBOL(v9fs_register_trans);
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/**
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* v9fs_unregister_trans - unregister a 9p transport
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* @m: the transport to remove
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*
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*/
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void v9fs_unregister_trans(struct p9_trans_module *m)
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{
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spin_lock(&v9fs_trans_lock);
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list_del_init(&m->list);
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spin_unlock(&v9fs_trans_lock);
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}
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EXPORT_SYMBOL(v9fs_unregister_trans);
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/**
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* v9fs_get_trans_by_name - get transport with the matching name
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* @name: string identifying transport
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*
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*/
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struct p9_trans_module *v9fs_get_trans_by_name(const substring_t *name)
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{
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struct p9_trans_module *t, *found = NULL;
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spin_lock(&v9fs_trans_lock);
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list_for_each_entry(t, &v9fs_trans_list, list)
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if (strncmp(t->name, name->from, name->to-name->from) == 0 &&
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try_module_get(t->owner)) {
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found = t;
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break;
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}
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spin_unlock(&v9fs_trans_lock);
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return found;
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}
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EXPORT_SYMBOL(v9fs_get_trans_by_name);
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/**
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* v9fs_get_default_trans - get the default transport
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*
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*/
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struct p9_trans_module *v9fs_get_default_trans(void)
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{
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struct p9_trans_module *t, *found = NULL;
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spin_lock(&v9fs_trans_lock);
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list_for_each_entry(t, &v9fs_trans_list, list)
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if (t->def && try_module_get(t->owner)) {
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found = t;
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break;
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}
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if (!found)
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list_for_each_entry(t, &v9fs_trans_list, list)
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if (try_module_get(t->owner)) {
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found = t;
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break;
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}
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spin_unlock(&v9fs_trans_lock);
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return found;
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}
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EXPORT_SYMBOL(v9fs_get_default_trans);
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/**
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* v9fs_put_trans - put trans
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* @m: transport to put
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*
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*/
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void v9fs_put_trans(struct p9_trans_module *m)
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{
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if (m)
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module_put(m->owner);
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}
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/**
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* v9fs_init - Initialize module
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*
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*/
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static int __init init_p9(void)
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{
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int ret = 0;
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p9_error_init();
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printk(KERN_INFO "Installing 9P2000 support\n");
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p9_trans_fd_init();
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return ret;
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}
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/**
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* v9fs_init - shutdown module
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*
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*/
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static void __exit exit_p9(void)
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{
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printk(KERN_INFO "Unloading 9P2000 support\n");
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p9_trans_fd_exit();
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}
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module_init(init_p9)
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module_exit(exit_p9)
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MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
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MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
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MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
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MODULE_LICENSE("GPL");
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