net/rds/transport.c

0001 /*
0002  * Copyright (c) 2006, 2017 Oracle and/or its affiliates. All rights reserved.
0003  *
0004  * This software is available to you under a choice of one of two
0005  * licenses.  You may choose to be licensed under the terms of the GNU
0006  * General Public License (GPL) Version 2, available from the file
0007  * COPYING in the main directory of this source tree, or the
0008  * OpenIB.org BSD license below:
0009  *
0010  *     Redistribution and use in source and binary forms, with or
0011  *     without modification, are permitted provided that the following
0012  *     conditions are met:
0013  *
0014  *      - Redistributions of source code must retain the above
0015  *        copyright notice, this list of conditions and the following
0016  *        disclaimer.
0017  *
0018  *      - Redistributions in binary form must reproduce the above
0019  *        copyright notice, this list of conditions and the following
0020  *        disclaimer in the documentation and/or other materials
0021  *        provided with the distribution.
0022  *
0023  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
0024  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
0025  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
0026  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
0027  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
0028  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
0029  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
0030  * SOFTWARE.
0031  *
0032  */
0033 #include <linux/kernel.h>
0034 #include <linux/module.h>
0035 #include <linux/in.h>
0036 #include <linux/ipv6.h>
0037
0038 #include "rds.h"
0039 #include "loop.h"
0040
0041 static char * const rds_trans_modules[] = {
0042     [RDS_TRANS_IB] = "rds_rdma",
0043     [RDS_TRANS_GAP] = NULL,
0044     [RDS_TRANS_TCP] = "rds_tcp",
0045 };
0046
0047 static struct rds_transport *transports[RDS_TRANS_COUNT];
0048 static DECLARE_RWSEM(rds_trans_sem);
0049
0050 void rds_trans_register(struct rds_transport *trans)
0051 {
0052     BUG_ON(strlen(trans->t_name) + 1 > TRANSNAMSIZ);
0053
0054     down_write(&rds_trans_sem);
0055
0056     if (transports[trans->t_type])
0057         printk(KERN_ERR "RDS Transport type %d already registered\n",
0058             trans->t_type);
0059     else {
0060         transports[trans->t_type] = trans;
0061         printk(KERN_INFO "Registered RDS/%s transport\n", trans->t_name);
0062     }
0063
0064     up_write(&rds_trans_sem);
0065 }
0066 EXPORT_SYMBOL_GPL(rds_trans_register);
0067
0068 void rds_trans_unregister(struct rds_transport *trans)
0069 {
0070     down_write(&rds_trans_sem);
0071
0072     transports[trans->t_type] = NULL;
0073     printk(KERN_INFO "Unregistered RDS/%s transport\n", trans->t_name);
0074
0075     up_write(&rds_trans_sem);
0076 }
0077 EXPORT_SYMBOL_GPL(rds_trans_unregister);
0078
0079 void rds_trans_put(struct rds_transport *trans)
0080 {
0081     if (trans)
0082         module_put(trans->t_owner);
0083 }
0084
0085 struct rds_transport *rds_trans_get_preferred(struct net *net,
0086                           const struct in6_addr *addr,
0087                           __u32 scope_id)
0088 {
0089     struct rds_transport *ret = NULL;
0090     struct rds_transport *trans;
0091     unsigned int i;
0092
0093     if (ipv6_addr_v4mapped(addr)) {
0094         if (*(u_int8_t *)&addr->s6_addr32[3] == IN_LOOPBACKNET)
0095             return &rds_loop_transport;
0096     } else if (ipv6_addr_loopback(addr)) {
0097         return &rds_loop_transport;
0098     }
0099
0100     down_read(&rds_trans_sem);
0101     for (i = 0; i < RDS_TRANS_COUNT; i++) {
0102         trans = transports[i];
0103
0104         if (trans && (trans->laddr_check(net, addr, scope_id) == 0) &&
0105             (!trans->t_owner || try_module_get(trans->t_owner))) {
0106             ret = trans;
0107             break;
0108         }
0109     }
0110     up_read(&rds_trans_sem);
0111
0112     return ret;
0113 }
0114
0115 struct rds_transport *rds_trans_get(int t_type)
0116 {
0117     struct rds_transport *ret = NULL;
0118     struct rds_transport *trans;
0119
0120     down_read(&rds_trans_sem);
0121     trans = transports[t_type];
0122     if (!trans) {
0123         up_read(&rds_trans_sem);
0124         if (rds_trans_modules[t_type])
0125             request_module(rds_trans_modules[t_type]);
0126         down_read(&rds_trans_sem);
0127         trans = transports[t_type];
0128     }
0129     if (trans && trans->t_type == t_type &&
0130         (!trans->t_owner || try_module_get(trans->t_owner)))
0131         ret = trans;
0132
0133     up_read(&rds_trans_sem);
0134
0135     return ret;
0136 }
0137
0138 /*
0139  * This returns the number of stats entries in the snapshot and only
0140  * copies them using the iter if there is enough space for them.  The
0141  * caller passes in the global stats so that we can size and copy while
0142  * holding the lock.
0143  */
0144 unsigned int rds_trans_stats_info_copy(struct rds_info_iterator *iter,
0145                        unsigned int avail)
0146
0147 {
0148     struct rds_transport *trans;
0149     unsigned int total = 0;
0150     unsigned int part;
0151     int i;
0152
0153     rds_info_iter_unmap(iter);
0154     down_read(&rds_trans_sem);
0155
0156     for (i = 0; i < RDS_TRANS_COUNT; i++) {
0157         trans = transports[i];
0158         if (!trans || !trans->stats_info_copy)
0159             continue;
0160
0161         part = trans->stats_info_copy(iter, avail);
0162         avail -= min(avail, part);
0163         total += part;
0164     }
0165
0166     up_read(&rds_trans_sem);
0167
0168     return total;
0169 }