Root/net/rds/transport.c

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
74struct rds_transport *rds_trans_get_preferred(__be32 addr)
75{
76    struct rds_transport *ret = NULL;
77    int i;
78
79    if (IN_LOOPBACK(ntohl(addr)))
80        return &rds_loop_transport;
81
82    down_read(&rds_trans_sem);
83    for (i = 0; i < RDS_TRANS_COUNT; i++)
84    {
85        if (transports[i] && (transports[i]->laddr_check(addr) == 0)) {
86            ret = transports[i];
87            break;
88        }
89    }
90    up_read(&rds_trans_sem);
91
92    return ret;
93}
94
95/*
96 * This returns the number of stats entries in the snapshot and only
97 * copies them using the iter if there is enough space for them. The
98 * caller passes in the global stats so that we can size and copy while
99 * holding the lock.
100 */
101unsigned int rds_trans_stats_info_copy(struct rds_info_iterator *iter,
102                       unsigned int avail)
103
104{
105    struct rds_transport *trans;
106    unsigned int total = 0;
107    unsigned int part;
108    int i;
109
110    rds_info_iter_unmap(iter);
111    down_read(&rds_trans_sem);
112
113    for (i = 0; i < RDS_TRANS_COUNT; i++)
114    {
115        trans = transports[i];
116        if (!trans || !trans->stats_info_copy)
117            continue;
118
119        part = trans->stats_info_copy(iter, avail);
120        avail -= min(avail, part);
121        total += part;
122    }
123
124    up_read(&rds_trans_sem);
125
126    return total;
127}
128
129

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