transport.c revision 616b757ae18fb8ec2dfe7ff9d3f589f82cb0eb9d 
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 LIST_HEAD(rds_transports);
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	list_add_tail(&trans->t_item, &rds_transports);
50	printk(KERN_INFO "Registered RDS/%s transport\n", trans->t_name);
51
52	up_write(&rds_trans_sem);
53
54	return 0;
55}
56EXPORT_SYMBOL_GPL(rds_trans_register);
57
58void rds_trans_unregister(struct rds_transport *trans)
59{
60	down_write(&rds_trans_sem);
61
62	list_del_init(&trans->t_item);
63	printk(KERN_INFO "Unregistered RDS/%s transport\n", trans->t_name);
64
65	up_write(&rds_trans_sem);
66}
67EXPORT_SYMBOL_GPL(rds_trans_unregister);
68
69struct rds_transport *rds_trans_get_preferred(__be32 addr)
70{
71	struct rds_transport *trans;
72	struct rds_transport *ret = NULL;
73
74	if (IN_LOOPBACK(ntohl(addr)))
75		return &rds_loop_transport;
76
77	down_read(&rds_trans_sem);
78	list_for_each_entry(trans, &rds_transports, t_item) {
79		if (trans->laddr_check(addr) == 0) {
80			ret = trans;
81			break;
82		}
83	}
84	up_read(&rds_trans_sem);
85
86	return ret;
87}
88
89/*
90 * This returns the number of stats entries in the snapshot and only
91 * copies them using the iter if there is enough space for them.  The
92 * caller passes in the global stats so that we can size and copy while
93 * holding the lock.
94 */
95unsigned int rds_trans_stats_info_copy(struct rds_info_iterator *iter,
96				       unsigned int avail)
97
98{
99	struct rds_transport *trans;
100	unsigned int total = 0;
101	unsigned int part;
102
103	rds_info_iter_unmap(iter);
104	down_read(&rds_trans_sem);
105
106	list_for_each_entry(trans, &rds_transports, t_item) {
107		if (trans->stats_info_copy == NULL)
108			continue;
109
110		part = trans->stats_info_copy(iter, avail);
111		avail -= min(avail, part);
112		total += part;
113	}
114
115	up_read(&rds_trans_sem);
116
117	return total;
118}
119
120