1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
|
/*
* Copyright (c) 2006 Oracle. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* OpenIB.org BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/in.h>
#include "rds.h"
#include "loop.h"
static DEFINE_SPINLOCK(loop_conns_lock);
static LIST_HEAD(loop_conns);
/*
* This 'loopback' transport is a special case for flows that originate
* and terminate on the same machine.
*
* Connection build-up notices if the destination address is thought of
* as a local address by a transport. At that time it decides to use the
* loopback transport instead of the bound transport of the sending socket.
*
* The loopback transport's sending path just hands the sent rds_message
* straight to the receiving path via an embedded rds_incoming.
*/
/*
* Usually a message transits both the sender and receiver's conns as it
* flows to the receiver. In the loopback case, though, the receive path
* is handed the sending conn so the sense of the addresses is reversed.
*/
static int rds_loop_xmit(struct rds_connection *conn, struct rds_message *rm,
unsigned int hdr_off, unsigned int sg,
unsigned int off)
{
struct scatterlist *sgp = &rm->data.op_sg[sg];
int ret = sizeof(struct rds_header) +
be32_to_cpu(rm->m_inc.i_hdr.h_len);
/* Do not send cong updates to loopback */
if (rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) {
rds_cong_map_updated(conn->c_fcong, ~(u64) 0);
ret = min_t(int, ret, sgp->length - conn->c_xmit_data_off);
goto out;
}
BUG_ON(hdr_off || sg || off);
rds_inc_init(&rm->m_inc, conn, conn->c_laddr);
/* For the embedded inc. Matching put is in loop_inc_free() */
rds_message_addref(rm);
rds_recv_incoming(conn, conn->c_laddr, conn->c_faddr, &rm->m_inc,
GFP_KERNEL);
rds_send_drop_acked(conn, be64_to_cpu(rm->m_inc.i_hdr.h_sequence),
NULL);
rds_inc_put(&rm->m_inc);
out:
return ret;
}
/*
* See rds_loop_xmit(). Since our inc is embedded in the rm, we
* make sure the rm lives at least until the inc is done.
*/
static void rds_loop_inc_free(struct rds_incoming *inc)
{
struct rds_message *rm = container_of(inc, struct rds_message, m_inc);
rds_message_put(rm);
}
/* we need to at least give the thread something to succeed */
static int rds_loop_recv(struct rds_connection *conn)
{
return 0;
}
struct rds_loop_connection {
struct list_head loop_node;
struct rds_connection *conn;
};
/*
* Even the loopback transport needs to keep track of its connections,
* so it can call rds_conn_destroy() on them on exit. N.B. there are
* 1+ loopback addresses (127.*.*.*) so it's not a bug to have
* multiple loopback conns allocated, although rather useless.
*/
static int rds_loop_conn_alloc(struct rds_connection *conn, gfp_t gfp)
{
struct rds_loop_connection *lc;
unsigned long flags;
lc = kzalloc(sizeof(struct rds_loop_connection), gfp);
if (!lc)
return -ENOMEM;
INIT_LIST_HEAD(&lc->loop_node);
lc->conn = conn;
conn->c_transport_data = lc;
spin_lock_irqsave(&loop_conns_lock, flags);
list_add_tail(&lc->loop_node, &loop_conns);
spin_unlock_irqrestore(&loop_conns_lock, flags);
return 0;
}
static void rds_loop_conn_free(void *arg)
{
struct rds_loop_connection *lc = arg;
unsigned long flags;
rdsdebug("lc %p\n", lc);
spin_lock_irqsave(&loop_conns_lock, flags);
list_del(&lc->loop_node);
spin_unlock_irqrestore(&loop_conns_lock, flags);
kfree(lc);
}
static int rds_loop_conn_connect(struct rds_connection *conn)
{
rds_connect_complete(conn);
return 0;
}
static void rds_loop_conn_shutdown(struct rds_connection *conn)
{
}
void rds_loop_exit(void)
{
struct rds_loop_connection *lc, *_lc;
LIST_HEAD(tmp_list);
/* avoid calling conn_destroy with irqs off */
spin_lock_irq(&loop_conns_lock);
list_splice(&loop_conns, &tmp_list);
INIT_LIST_HEAD(&loop_conns);
spin_unlock_irq(&loop_conns_lock);
list_for_each_entry_safe(lc, _lc, &tmp_list, loop_node) {
WARN_ON(lc->conn->c_passive);
rds_conn_destroy(lc->conn);
}
}
/*
* This is missing .xmit_* because loop doesn't go through generic
* rds_send_xmit() and doesn't call rds_recv_incoming(). .listen_stop and
* .laddr_check are missing because transport.c doesn't iterate over
* rds_loop_transport.
*/
struct rds_transport rds_loop_transport = {
.xmit = rds_loop_xmit,
.recv = rds_loop_recv,
.conn_alloc = rds_loop_conn_alloc,
.conn_free = rds_loop_conn_free,
.conn_connect = rds_loop_conn_connect,
.conn_shutdown = rds_loop_conn_shutdown,
.inc_copy_to_user = rds_message_inc_copy_to_user,
.inc_free = rds_loop_inc_free,
.t_name = "loopback",
};
|
