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/slab.h> 35 #include <linux/in.h> 36 37 #include "rds.h" 38 #include "loop.h" 39 40 static DEFINE_SPINLOCK(loop_conns_lock); 41 static LIST_HEAD(loop_conns); 42 43 /* 44 * This 'loopback' transport is a special case for flows that originate 45 * and terminate on the same machine. 46 * 47 * Connection build-up notices if the destination address is thought of 48 * as a local address by a transport. At that time it decides to use the 49 * loopback transport instead of the bound transport of the sending socket. 50 * 51 * The loopback transport's sending path just hands the sent rds_message 52 * straight to the receiving path via an embedded rds_incoming. 53 */ 54 55 /* 56 * Usually a message transits both the sender and receiver's conns as it 57 * flows to the receiver. In the loopback case, though, the receive path 58 * is handed the sending conn so the sense of the addresses is reversed. 59 */ 60 static int rds_loop_xmit(struct rds_connection *conn, struct rds_message *rm, 61 unsigned int hdr_off, unsigned int sg, 62 unsigned int off) 63 { 64 BUG_ON(hdr_off || sg || off); 65 66 rds_inc_init(&rm->m_inc, conn, conn->c_laddr); 67 rds_message_addref(rm); /* for the inc */ 68 69 rds_recv_incoming(conn, conn->c_laddr, conn->c_faddr, &rm->m_inc, 70 GFP_KERNEL, KM_USER0); 71 72 rds_send_drop_acked(conn, be64_to_cpu(rm->m_inc.i_hdr.h_sequence), 73 NULL); 74 75 rds_inc_put(&rm->m_inc); 76 77 return sizeof(struct rds_header) + be32_to_cpu(rm->m_inc.i_hdr.h_len); 78 } 79 80 static int rds_loop_xmit_cong_map(struct rds_connection *conn, 81 struct rds_cong_map *map, 82 unsigned long offset) 83 { 84 unsigned long i; 85 86 BUG_ON(offset); 87 BUG_ON(map != conn->c_lcong); 88 89 for (i = 0; i < RDS_CONG_MAP_PAGES; i++) { 90 memcpy((void *)conn->c_fcong->m_page_addrs[i], 91 (void *)map->m_page_addrs[i], PAGE_SIZE); 92 } 93 94 rds_cong_map_updated(conn->c_fcong, ~(u64) 0); 95 96 return sizeof(struct rds_header) + RDS_CONG_MAP_BYTES; 97 } 98 99 /* we need to at least give the thread something to succeed */ 100 static int rds_loop_recv(struct rds_connection *conn) 101 { 102 return 0; 103 } 104 105 struct rds_loop_connection { 106 struct list_head loop_node; 107 struct rds_connection *conn; 108 }; 109 110 /* 111 * Even the loopback transport needs to keep track of its connections, 112 * so it can call rds_conn_destroy() on them on exit. N.B. there are 113 * 1+ loopback addresses (127.*.*.*) so it's not a bug to have 114 * multiple loopback conns allocated, although rather useless. 115 */ 116 static int rds_loop_conn_alloc(struct rds_connection *conn, gfp_t gfp) 117 { 118 struct rds_loop_connection *lc; 119 unsigned long flags; 120 121 lc = kzalloc(sizeof(struct rds_loop_connection), GFP_KERNEL); 122 if (lc == NULL) 123 return -ENOMEM; 124 125 INIT_LIST_HEAD(&lc->loop_node); 126 lc->conn = conn; 127 conn->c_transport_data = lc; 128 129 spin_lock_irqsave(&loop_conns_lock, flags); 130 list_add_tail(&lc->loop_node, &loop_conns); 131 spin_unlock_irqrestore(&loop_conns_lock, flags); 132 133 return 0; 134 } 135 136 static void rds_loop_conn_free(void *arg) 137 { 138 struct rds_loop_connection *lc = arg; 139 rdsdebug("lc %p\n", lc); 140 list_del(&lc->loop_node); 141 kfree(lc); 142 } 143 144 static int rds_loop_conn_connect(struct rds_connection *conn) 145 { 146 rds_connect_complete(conn); 147 return 0; 148 } 149 150 static void rds_loop_conn_shutdown(struct rds_connection *conn) 151 { 152 } 153 154 void rds_loop_exit(void) 155 { 156 struct rds_loop_connection *lc, *_lc; 157 LIST_HEAD(tmp_list); 158 159 /* avoid calling conn_destroy with irqs off */ 160 spin_lock_irq(&loop_conns_lock); 161 list_splice(&loop_conns, &tmp_list); 162 INIT_LIST_HEAD(&loop_conns); 163 spin_unlock_irq(&loop_conns_lock); 164 165 list_for_each_entry_safe(lc, _lc, &tmp_list, loop_node) { 166 WARN_ON(lc->conn->c_passive); 167 rds_conn_destroy(lc->conn); 168 } 169 } 170 171 /* 172 * This is missing .xmit_* because loop doesn't go through generic 173 * rds_send_xmit() and doesn't call rds_recv_incoming(). .listen_stop and 174 * .laddr_check are missing because transport.c doesn't iterate over 175 * rds_loop_transport. 176 */ 177 struct rds_transport rds_loop_transport = { 178 .xmit = rds_loop_xmit, 179 .xmit_cong_map = rds_loop_xmit_cong_map, 180 .recv = rds_loop_recv, 181 .conn_alloc = rds_loop_conn_alloc, 182 .conn_free = rds_loop_conn_free, 183 .conn_connect = rds_loop_conn_connect, 184 .conn_shutdown = rds_loop_conn_shutdown, 185 .inc_copy_to_user = rds_message_inc_copy_to_user, 186 .inc_purge = rds_message_inc_purge, 187 .inc_free = rds_message_inc_free, 188 .t_name = "loopback", 189 }; 190