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/in.h> 35 36 #include "rds.h" 37 #include "loop.h" 38 39 static DEFINE_SPINLOCK(loop_conns_lock); 40 static LIST_HEAD(loop_conns); 41 42 /* 43 * This 'loopback' transport is a special case for flows that originate 44 * and terminate on the same machine. 45 * 46 * Connection build-up notices if the destination address is thought of 47 * as a local address by a transport. At that time it decides to use the 48 * loopback transport instead of the bound transport of the sending socket. 49 * 50 * The loopback transport's sending path just hands the sent rds_message 51 * straight to the receiving path via an embedded rds_incoming. 52 */ 53 54 /* 55 * Usually a message transits both the sender and receiver's conns as it 56 * flows to the receiver. In the loopback case, though, the receive path 57 * is handed the sending conn so the sense of the addresses is reversed. 58 */ 59 static int rds_loop_xmit(struct rds_connection *conn, struct rds_message *rm, 60 unsigned int hdr_off, unsigned int sg, 61 unsigned int off) 62 { 63 BUG_ON(hdr_off || sg || off); 64 65 rds_inc_init(&rm->m_inc, conn, conn->c_laddr); 66 rds_message_addref(rm); /* for the inc */ 67 68 rds_recv_incoming(conn, conn->c_laddr, conn->c_faddr, &rm->m_inc, 69 GFP_KERNEL, KM_USER0); 70 71 rds_send_drop_acked(conn, be64_to_cpu(rm->m_inc.i_hdr.h_sequence), 72 NULL); 73 74 rds_inc_put(&rm->m_inc); 75 76 return sizeof(struct rds_header) + be32_to_cpu(rm->m_inc.i_hdr.h_len); 77 } 78 79 static int rds_loop_xmit_cong_map(struct rds_connection *conn, 80 struct rds_cong_map *map, 81 unsigned long offset) 82 { 83 unsigned long i; 84 85 BUG_ON(offset); 86 BUG_ON(map != conn->c_lcong); 87 88 for (i = 0; i < RDS_CONG_MAP_PAGES; i++) { 89 memcpy((void *)conn->c_fcong->m_page_addrs[i], 90 (void *)map->m_page_addrs[i], PAGE_SIZE); 91 } 92 93 rds_cong_map_updated(conn->c_fcong, ~(u64) 0); 94 95 return sizeof(struct rds_header) + RDS_CONG_MAP_BYTES; 96 } 97 98 /* we need to at least give the thread something to succeed */ 99 static int rds_loop_recv(struct rds_connection *conn) 100 { 101 return 0; 102 } 103 104 struct rds_loop_connection { 105 struct list_head loop_node; 106 struct rds_connection *conn; 107 }; 108 109 /* 110 * Even the loopback transport needs to keep track of its connections, 111 * so it can call rds_conn_destroy() on them on exit. N.B. there are 112 * 1+ loopback addresses (127.*.*.*) so it's not a bug to have 113 * multiple loopback conns allocated, although rather useless. 114 */ 115 static int rds_loop_conn_alloc(struct rds_connection *conn, gfp_t gfp) 116 { 117 struct rds_loop_connection *lc; 118 unsigned long flags; 119 120 lc = kzalloc(sizeof(struct rds_loop_connection), GFP_KERNEL); 121 if (lc == NULL) 122 return -ENOMEM; 123 124 INIT_LIST_HEAD(&lc->loop_node); 125 lc->conn = conn; 126 conn->c_transport_data = lc; 127 128 spin_lock_irqsave(&loop_conns_lock, flags); 129 list_add_tail(&lc->loop_node, &loop_conns); 130 spin_unlock_irqrestore(&loop_conns_lock, flags); 131 132 return 0; 133 } 134 135 static void rds_loop_conn_free(void *arg) 136 { 137 struct rds_loop_connection *lc = arg; 138 rdsdebug("lc %p\n", lc); 139 list_del(&lc->loop_node); 140 kfree(lc); 141 } 142 143 static int rds_loop_conn_connect(struct rds_connection *conn) 144 { 145 rds_connect_complete(conn); 146 return 0; 147 } 148 149 static void rds_loop_conn_shutdown(struct rds_connection *conn) 150 { 151 } 152 153 void rds_loop_exit(void) 154 { 155 struct rds_loop_connection *lc, *_lc; 156 LIST_HEAD(tmp_list); 157 158 /* avoid calling conn_destroy with irqs off */ 159 spin_lock_irq(&loop_conns_lock); 160 list_splice(&loop_conns, &tmp_list); 161 INIT_LIST_HEAD(&loop_conns); 162 spin_unlock_irq(&loop_conns_lock); 163 164 list_for_each_entry_safe(lc, _lc, &tmp_list, loop_node) { 165 WARN_ON(lc->conn->c_passive); 166 rds_conn_destroy(lc->conn); 167 } 168 } 169 170 /* 171 * This is missing .xmit_* because loop doesn't go through generic 172 * rds_send_xmit() and doesn't call rds_recv_incoming(). .listen_stop and 173 * .laddr_check are missing because transport.c doesn't iterate over 174 * rds_loop_transport. 175 */ 176 struct rds_transport rds_loop_transport = { 177 .xmit = rds_loop_xmit, 178 .xmit_cong_map = rds_loop_xmit_cong_map, 179 .recv = rds_loop_recv, 180 .conn_alloc = rds_loop_conn_alloc, 181 .conn_free = rds_loop_conn_free, 182 .conn_connect = rds_loop_conn_connect, 183 .conn_shutdown = rds_loop_conn_shutdown, 184 .inc_copy_to_user = rds_message_inc_copy_to_user, 185 .inc_purge = rds_message_inc_purge, 186 .inc_free = rds_message_inc_free, 187 .t_name = "loopback", 188 }; 189