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![Thomas Weißschuh](/assets/img/avatar_default.png)
Now that all transports are split into modules it may happen that no transports are registered when v9fs_get_default_trans() is called. When that is the case try to load more transports from modules. Link: https://lkml.kernel.org/r/20211103193823.111007-5-linux@weissschuh.net Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> [Dominique: constify v9fs_get_trans_by_name argument as per patch1v2] Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
212 lines
4.3 KiB
C
212 lines
4.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/kmod.h>
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#include <linux/errno.h>
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#include <linux/sched.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/client.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; /* 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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void _p9_debug(enum p9_debug_flags level, const char *func,
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const char *fmt, ...)
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{
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struct va_format vaf;
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va_list args;
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if ((p9_debug_level & level) != level)
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return;
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va_start(args, fmt);
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vaf.fmt = fmt;
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vaf.va = &args;
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if (level == P9_DEBUG_9P)
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pr_notice("(%8.8d) %pV", task_pid_nr(current), &vaf);
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else
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pr_notice("-- %s (%d): %pV", func, task_pid_nr(current), &vaf);
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va_end(args);
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}
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EXPORT_SYMBOL(_p9_debug);
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#endif
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/* Dynamic Transport Registration Routines */
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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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static struct p9_trans_module *_p9_get_trans_by_name(const char *s)
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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 (strcmp(t->name, s) == 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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/**
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* v9fs_get_trans_by_name - get transport with the matching name
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* @s: 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 char *s)
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{
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struct p9_trans_module *found = NULL;
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found = _p9_get_trans_by_name(s);
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#ifdef CONFIG_MODULES
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if (!found) {
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request_module("9p-%s", s);
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found = _p9_get_trans_by_name(s);
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}
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#endif
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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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static const char * const v9fs_default_transports[] = {
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"virtio", "tcp", "fd", "unix", "xen", "rdma",
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};
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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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int i;
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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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for (i = 0; !found && i < ARRAY_SIZE(v9fs_default_transports); i++)
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found = v9fs_get_trans_by_name(v9fs_default_transports[i]);
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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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* init_p9 - 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;
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ret = p9_client_init();
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if (ret)
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return ret;
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p9_error_init();
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pr_info("Installing 9P2000 support\n");
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return ret;
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}
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/**
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* exit_p9 - 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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pr_info("Unloading 9P2000 support\n");
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p9_client_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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MODULE_DESCRIPTION("Plan 9 Resource Sharing Support (9P2000)");
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