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-rw-r--r--net/rds/loop.c188
-rw-r--r--net/rds/loop.h9
2 files changed, 197 insertions, 0 deletions
diff --git a/net/rds/loop.c b/net/rds/loop.c
new file mode 100644
index 000000000000..4a61997f554d
--- /dev/null
+++ b/net/rds/loop.c
@@ -0,0 +1,188 @@
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
39static DEFINE_SPINLOCK(loop_conns_lock);
40static 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 */
59static 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
79static 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 */
99static int rds_loop_recv(struct rds_connection *conn)
100{
101 return 0;
102}
103
104struct 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 */
115static 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
135static 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
143static int rds_loop_conn_connect(struct rds_connection *conn)
144{
145 rds_connect_complete(conn);
146 return 0;
147}
148
149static void rds_loop_conn_shutdown(struct rds_connection *conn)
150{
151}
152
153void 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 */
176struct 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};
diff --git a/net/rds/loop.h b/net/rds/loop.h
new file mode 100644
index 000000000000..f32b0939a04d
--- /dev/null
+++ b/net/rds/loop.h
@@ -0,0 +1,9 @@
1#ifndef _RDS_LOOP_H
2#define _RDS_LOOP_H
3
4/* loop.c */
5extern struct rds_transport rds_loop_transport;
6
7void rds_loop_exit(void);
8
9#endif
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