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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
40 static struct rds_transport *transports[RDS_TRANS_COUNT];
41 static DECLARE_RWSEM(rds_trans_sem);
42
43 int 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 }
61 EXPORT_SYMBOL_GPL(rds_trans_register);
62
63 void 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 }
72 EXPORT_SYMBOL_GPL(rds_trans_unregister);
73
74 void rds_trans_put(struct rds_transport *trans)
75 {
76 if (trans)
77 module_put(trans->t_owner);
78 }
79
80 struct 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
104 struct 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 */
131 unsigned 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 trans = transports[i];
145 if (!trans || !trans->stats_info_copy)
146 continue;
147
148 part = trans->stats_info_copy(iter, avail);
149 avail -= min(avail, part);
150 total += part;
151 }
152
153 up_read(&rds_trans_sem);
154
155 return total;
156 }
157