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 } 157 158