LXR linux/net/rds/transport.c

   1/*
   2 * Copyright (c) 2006, 2017 Oracle and/or its affiliates. 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#include <linux/ipv6.h>
  37
  38#include "rds.h"
  39#include "loop.h"
  40
  41static char * const rds_trans_modules[] = {
  42        [RDS_TRANS_IB] = "rds_rdma",
  43        [RDS_TRANS_GAP] = NULL,
  44        [RDS_TRANS_TCP] = "rds_tcp",
  45};
  46
  47static struct rds_transport *transports[RDS_TRANS_COUNT];
  48static DECLARE_RWSEM(rds_trans_sem);
  49
  50void rds_trans_register(struct rds_transport *trans)
  51{
  52        BUG_ON(strlen(trans->t_name) + 1 > TRANSNAMSIZ);
  53
  54        down_write(&rds_trans_sem);
  55
  56        if (transports[trans->t_type])
  57                printk(KERN_ERR "RDS Transport type %d already registered\n",
  58                        trans->t_type);
  59        else {
  60                transports[trans->t_type] = trans;
  61                printk(KERN_INFO "Registered RDS/%s transport\n", trans->t_name);
  62        }
  63
  64        up_write(&rds_trans_sem);
  65}
  66EXPORT_SYMBOL_GPL(rds_trans_register);
  67
  68void rds_trans_unregister(struct rds_transport *trans)
  69{
  70        down_write(&rds_trans_sem);
  71
  72        transports[trans->t_type] = NULL;
  73        printk(KERN_INFO "Unregistered RDS/%s transport\n", trans->t_name);
  74
  75        up_write(&rds_trans_sem);
  76}
  77EXPORT_SYMBOL_GPL(rds_trans_unregister);
  78
  79void rds_trans_put(struct rds_transport *trans)
  80{
  81        if (trans)
  82                module_put(trans->t_owner);
  83}
  84
  85struct rds_transport *rds_trans_get_preferred(struct net *net,
  86                                              const struct in6_addr *addr,
  87                                              __u32 scope_id)
  88{
  89        struct rds_transport *ret = NULL;
  90        struct rds_transport *trans;
  91        unsigned int i;
  92
  93        if (ipv6_addr_v4mapped(addr)) {
  94                if (*(u_int8_t *)&addr->s6_addr32[3] == IN_LOOPBACKNET)
  95                        return &rds_loop_transport;
  96        } else if (ipv6_addr_loopback(addr)) {
  97                return &rds_loop_transport;
  98        }
  99
 100        down_read(&rds_trans_sem);
 101        for (i = 0; i < RDS_TRANS_COUNT; i++) {
 102                trans = transports[i];
 103
 104                if (trans && (trans->laddr_check(net, addr, scope_id) == 0) &&
 105                    (!trans->t_owner || try_module_get(trans->t_owner))) {
 106                        ret = trans;
 107                        break;
 108                }
 109        }
 110        up_read(&rds_trans_sem);
 111
 112        return ret;
 113}
 114
 115struct rds_transport *rds_trans_get(int t_type)
 116{
 117        struct rds_transport *ret = NULL;
 118        struct rds_transport *trans;
 119
 120        down_read(&rds_trans_sem);
 121        trans = transports[t_type];
 122        if (!trans) {
 123                up_read(&rds_trans_sem);
 124                if (rds_trans_modules[t_type])
 125                        request_module(rds_trans_modules[t_type]);
 126                down_read(&rds_trans_sem);
 127                trans = transports[t_type];
 128        }
 129        if (trans && trans->t_type == t_type &&
 130            (!trans->t_owner || try_module_get(trans->t_owner)))
 131                ret = trans;
 132
 133        up_read(&rds_trans_sem);
 134
 135        return ret;
 136}
 137
 138/*
 139 * This returns the number of stats entries in the snapshot and only
 140 * copies them using the iter if there is enough space for them.  The
 141 * caller passes in the global stats so that we can size and copy while
 142 * holding the lock.
 143 */
 144unsigned int rds_trans_stats_info_copy(struct rds_info_iterator *iter,
 145                                       unsigned int avail)
 146
 147{
 148        struct rds_transport *trans;
 149        unsigned int total = 0;
 150        unsigned int part;
 151        int i;
 152
 153        rds_info_iter_unmap(iter);
 154        down_read(&rds_trans_sem);
 155
 156        for (i = 0; i < RDS_TRANS_COUNT; i++) {
 157                trans = transports[i];
 158                if (!trans || !trans->stats_info_copy)
 159                        continue;
 160
 161                part = trans->stats_info_copy(iter, avail);
 162                avail -= min(avail, part);
 163                total += part;
 164        }
 165
 166        up_read(&rds_trans_sem);
 167
 168        return total;
 169}
 170