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Andy Grover13796bf2009-02-24 15:30:24 +00001/*
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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090034#include <linux/slab.h>
Andy Grover13796bf2009-02-24 15:30:24 +000035#include <linux/in.h>
36
37#include "rds.h"
38#include "loop.h"
39
40static DEFINE_SPINLOCK(loop_conns_lock);
41static 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 */
60static 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
80static 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 */
100static int rds_loop_recv(struct rds_connection *conn)
101{
102 return 0;
103}
104
105struct 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 */
116static 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
136static 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
144static int rds_loop_conn_connect(struct rds_connection *conn)
145{
146 rds_connect_complete(conn);
147 return 0;
148}
149
150static void rds_loop_conn_shutdown(struct rds_connection *conn)
151{
152}
153
154void 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 */
177struct 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};