1/*
2 * Copyright (c) 2006 Oracle.  All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses.  You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
9 *
10 *     Redistribution and use in source and binary forms, with or
11 *     without modification, are permitted provided that the following
12 *     conditions are met:
13 *
14 *      - Redistributions of source code must retain the above
15 *        copyright notice, this list of conditions and the following
16 *        disclaimer.
17 *
18 *      - Redistributions in binary form must reproduce the above
19 *        copyright notice, this list of conditions and the following
20 *        disclaimer in the documentation and/or other materials
21 *        provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 *
32 */
33#include <linux/kernel.h>
34#include <linux/module.h>
35#include <linux/in.h>
36
37#include "rds.h"
38#include "loop.h"
39
40static struct rds_transport *transports[RDS_TRANS_COUNT];
41static DECLARE_RWSEM(rds_trans_sem);
42
43int rds_trans_register(struct rds_transport *trans)
44{
45	BUG_ON(strlen(trans->t_name) + 1 > TRANSNAMSIZ);
46
47	down_write(&rds_trans_sem);
48
49	if (transports[trans->t_type])
50		printk(KERN_ERR "RDS Transport type %d already registered\n",
51			trans->t_type);
52	else {
53		transports[trans->t_type] = trans;
54		printk(KERN_INFO "Registered RDS/%s transport\n", trans->t_name);
55	}
56
57	up_write(&rds_trans_sem);
58
59	return 0;
60}
61EXPORT_SYMBOL_GPL(rds_trans_register);
62
63void rds_trans_unregister(struct rds_transport *trans)
64{
65	down_write(&rds_trans_sem);
66
67	transports[trans->t_type] = NULL;
68	printk(KERN_INFO "Unregistered RDS/%s transport\n", trans->t_name);
69
70	up_write(&rds_trans_sem);
71}
72EXPORT_SYMBOL_GPL(rds_trans_unregister);
73
74void rds_trans_put(struct rds_transport *trans)
75{
76	if (trans)
77		module_put(trans->t_owner);
78}
79
80struct rds_transport *rds_trans_get_preferred(struct net *net, __be32 addr)
81{
82	struct rds_transport *ret = NULL;
83	struct rds_transport *trans;
84	unsigned int i;
85
86	if (IN_LOOPBACK(ntohl(addr)))
87		return &rds_loop_transport;
88
89	down_read(&rds_trans_sem);
90	for (i = 0; i < RDS_TRANS_COUNT; i++) {
91		trans = transports[i];
92
93		if (trans && (trans->laddr_check(net, addr) == 0) &&
94		    (!trans->t_owner || try_module_get(trans->t_owner))) {
95			ret = trans;
96			break;
97		}
98	}
99	up_read(&rds_trans_sem);
100
101	return ret;
102}
103
104struct rds_transport *rds_trans_get(int t_type)
105{
106	struct rds_transport *ret = NULL;
107	struct rds_transport *trans;
108	unsigned int i;
109
110	down_read(&rds_trans_sem);
111	for (i = 0; i < RDS_TRANS_COUNT; i++) {
112		trans = transports[i];
113
114		if (trans && trans->t_type == t_type &&
115		    (!trans->t_owner || try_module_get(trans->t_owner))) {
116			ret = trans;
117			break;
118		}
119	}
120	up_read(&rds_trans_sem);
121
122	return ret;
123}
124
125/*
126 * This returns the number of stats entries in the snapshot and only
127 * copies them using the iter if there is enough space for them.  The
128 * caller passes in the global stats so that we can size and copy while
129 * holding the lock.
130 */
131unsigned int rds_trans_stats_info_copy(struct rds_info_iterator *iter,
132				       unsigned int avail)
133
134{
135	struct rds_transport *trans;
136	unsigned int total = 0;
137	unsigned int part;
138	int i;
139
140	rds_info_iter_unmap(iter);
141	down_read(&rds_trans_sem);
142
143	for (i = 0; i < RDS_TRANS_COUNT; i++)
144	{
145		trans = transports[i];
146		if (!trans || !trans->stats_info_copy)
147			continue;
148
149		part = trans->stats_info_copy(iter, avail);
150		avail -= min(avail, part);
151		total += part;
152	}
153
154	up_read(&rds_trans_sem);
155
156	return total;
157}
158
159