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13796bf9 AG |
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> | |
5a0e3ad6 | 34 | #include <linux/slab.h> |
13796bf9 AG |
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 | { | |
13796bf9 AG |
84 | BUG_ON(offset); |
85 | BUG_ON(map != conn->c_lcong); | |
86 | ||
13796bf9 AG |
87 | rds_cong_map_updated(conn->c_fcong, ~(u64) 0); |
88 | ||
89 | return sizeof(struct rds_header) + RDS_CONG_MAP_BYTES; | |
90 | } | |
91 | ||
92 | /* we need to at least give the thread something to succeed */ | |
93 | static int rds_loop_recv(struct rds_connection *conn) | |
94 | { | |
95 | return 0; | |
96 | } | |
97 | ||
98 | struct rds_loop_connection { | |
99 | struct list_head loop_node; | |
100 | struct rds_connection *conn; | |
101 | }; | |
102 | ||
103 | /* | |
104 | * Even the loopback transport needs to keep track of its connections, | |
105 | * so it can call rds_conn_destroy() on them on exit. N.B. there are | |
106 | * 1+ loopback addresses (127.*.*.*) so it's not a bug to have | |
107 | * multiple loopback conns allocated, although rather useless. | |
108 | */ | |
109 | static int rds_loop_conn_alloc(struct rds_connection *conn, gfp_t gfp) | |
110 | { | |
111 | struct rds_loop_connection *lc; | |
112 | unsigned long flags; | |
113 | ||
114 | lc = kzalloc(sizeof(struct rds_loop_connection), GFP_KERNEL); | |
8690bfa1 | 115 | if (!lc) |
13796bf9 AG |
116 | return -ENOMEM; |
117 | ||
118 | INIT_LIST_HEAD(&lc->loop_node); | |
119 | lc->conn = conn; | |
120 | conn->c_transport_data = lc; | |
121 | ||
122 | spin_lock_irqsave(&loop_conns_lock, flags); | |
123 | list_add_tail(&lc->loop_node, &loop_conns); | |
124 | spin_unlock_irqrestore(&loop_conns_lock, flags); | |
125 | ||
126 | return 0; | |
127 | } | |
128 | ||
129 | static void rds_loop_conn_free(void *arg) | |
130 | { | |
131 | struct rds_loop_connection *lc = arg; | |
132 | rdsdebug("lc %p\n", lc); | |
133 | list_del(&lc->loop_node); | |
134 | kfree(lc); | |
135 | } | |
136 | ||
137 | static int rds_loop_conn_connect(struct rds_connection *conn) | |
138 | { | |
139 | rds_connect_complete(conn); | |
140 | return 0; | |
141 | } | |
142 | ||
143 | static void rds_loop_conn_shutdown(struct rds_connection *conn) | |
144 | { | |
145 | } | |
146 | ||
147 | void rds_loop_exit(void) | |
148 | { | |
149 | struct rds_loop_connection *lc, *_lc; | |
150 | LIST_HEAD(tmp_list); | |
151 | ||
152 | /* avoid calling conn_destroy with irqs off */ | |
153 | spin_lock_irq(&loop_conns_lock); | |
154 | list_splice(&loop_conns, &tmp_list); | |
155 | INIT_LIST_HEAD(&loop_conns); | |
156 | spin_unlock_irq(&loop_conns_lock); | |
157 | ||
158 | list_for_each_entry_safe(lc, _lc, &tmp_list, loop_node) { | |
159 | WARN_ON(lc->conn->c_passive); | |
160 | rds_conn_destroy(lc->conn); | |
161 | } | |
162 | } | |
163 | ||
164 | /* | |
165 | * This is missing .xmit_* because loop doesn't go through generic | |
166 | * rds_send_xmit() and doesn't call rds_recv_incoming(). .listen_stop and | |
167 | * .laddr_check are missing because transport.c doesn't iterate over | |
168 | * rds_loop_transport. | |
169 | */ | |
170 | struct rds_transport rds_loop_transport = { | |
171 | .xmit = rds_loop_xmit, | |
172 | .xmit_cong_map = rds_loop_xmit_cong_map, | |
173 | .recv = rds_loop_recv, | |
174 | .conn_alloc = rds_loop_conn_alloc, | |
175 | .conn_free = rds_loop_conn_free, | |
176 | .conn_connect = rds_loop_conn_connect, | |
177 | .conn_shutdown = rds_loop_conn_shutdown, | |
178 | .inc_copy_to_user = rds_message_inc_copy_to_user, | |
13796bf9 AG |
179 | .inc_free = rds_message_inc_free, |
180 | .t_name = "loopback", | |
181 | }; |