xref: /linux/net/rds/transport.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
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 void 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 EXPORT_SYMBOL_GPL(rds_trans_register);
60 
61 void rds_trans_unregister(struct rds_transport *trans)
62 {
63 	down_write(&rds_trans_sem);
64 
65 	transports[trans->t_type] = NULL;
66 	printk(KERN_INFO "Unregistered RDS/%s transport\n", trans->t_name);
67 
68 	up_write(&rds_trans_sem);
69 }
70 EXPORT_SYMBOL_GPL(rds_trans_unregister);
71 
72 void rds_trans_put(struct rds_transport *trans)
73 {
74 	if (trans)
75 		module_put(trans->t_owner);
76 }
77 
78 struct rds_transport *rds_trans_get_preferred(struct net *net, __be32 addr)
79 {
80 	struct rds_transport *ret = NULL;
81 	struct rds_transport *trans;
82 	unsigned int i;
83 
84 	if (IN_LOOPBACK(ntohl(addr)))
85 		return &rds_loop_transport;
86 
87 	down_read(&rds_trans_sem);
88 	for (i = 0; i < RDS_TRANS_COUNT; i++) {
89 		trans = transports[i];
90 
91 		if (trans && (trans->laddr_check(net, addr) == 0) &&
92 		    (!trans->t_owner || try_module_get(trans->t_owner))) {
93 			ret = trans;
94 			break;
95 		}
96 	}
97 	up_read(&rds_trans_sem);
98 
99 	return ret;
100 }
101 
102 struct rds_transport *rds_trans_get(int t_type)
103 {
104 	struct rds_transport *ret = NULL;
105 	struct rds_transport *trans;
106 	unsigned int i;
107 
108 	down_read(&rds_trans_sem);
109 	for (i = 0; i < RDS_TRANS_COUNT; i++) {
110 		trans = transports[i];
111 
112 		if (trans && trans->t_type == t_type &&
113 		    (!trans->t_owner || try_module_get(trans->t_owner))) {
114 			ret = trans;
115 			break;
116 		}
117 	}
118 	up_read(&rds_trans_sem);
119 
120 	return ret;
121 }
122 
123 /*
124  * This returns the number of stats entries in the snapshot and only
125  * copies them using the iter if there is enough space for them.  The
126  * caller passes in the global stats so that we can size and copy while
127  * holding the lock.
128  */
129 unsigned int rds_trans_stats_info_copy(struct rds_info_iterator *iter,
130 				       unsigned int avail)
131 
132 {
133 	struct rds_transport *trans;
134 	unsigned int total = 0;
135 	unsigned int part;
136 	int i;
137 
138 	rds_info_iter_unmap(iter);
139 	down_read(&rds_trans_sem);
140 
141 	for (i = 0; i < RDS_TRANS_COUNT; i++) {
142 		trans = transports[i];
143 		if (!trans || !trans->stats_info_copy)
144 			continue;
145 
146 		part = trans->stats_info_copy(iter, avail);
147 		avail -= min(avail, part);
148 		total += part;
149 	}
150 
151 	up_read(&rds_trans_sem);
152 
153 	return total;
154 }
155 
156