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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#include <net/tcp.h>
36
37#include "rds.h"
38#include "tcp.h"
39
40static void rds_tcp_cork(struct socket *sock, int val)
41{
42 mm_segment_t oldfs;
43
44 oldfs = get_fs();
45 set_fs(KERNEL_DS);
46 sock->ops->setsockopt(sock, SOL_TCP, TCP_CORK, (char __user *)&val,
47 sizeof(val));
48 set_fs(oldfs);
49}
50
51void rds_tcp_xmit_prepare(struct rds_connection *conn)
52{
53 struct rds_tcp_connection *tc = conn->c_transport_data;
54
55 rds_tcp_cork(tc->t_sock, 1);
56}
57
58void rds_tcp_xmit_complete(struct rds_connection *conn)
59{
60 struct rds_tcp_connection *tc = conn->c_transport_data;
61
62 rds_tcp_cork(tc->t_sock, 0);
63}
64
65/* the core send_sem serializes this with other xmit and shutdown */
66static int rds_tcp_sendmsg(struct socket *sock, void *data, unsigned int len)
67{
68 struct kvec vec = {
69 .iov_base = data,
70 .iov_len = len,
71 };
72 struct msghdr msg = {
73 .msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL,
74 };
75
76 return kernel_sendmsg(sock, &msg, &vec, 1, vec.iov_len);
77}
78
79/* the core send_sem serializes this with other xmit and shutdown */
80int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm,
81 unsigned int hdr_off, unsigned int sg, unsigned int off)
82{
83 struct rds_tcp_connection *tc = conn->c_transport_data;
84 int done = 0;
85 int ret = 0;
86 int more;
87
88 if (hdr_off == 0) {
89 /*
90 * m_ack_seq is set to the sequence number of the last byte of
91 * header and data. see rds_tcp_is_acked().
92 */
93 tc->t_last_sent_nxt = rds_tcp_snd_nxt(tc);
94 rm->m_ack_seq = tc->t_last_sent_nxt +
95 sizeof(struct rds_header) +
96 be32_to_cpu(rm->m_inc.i_hdr.h_len) - 1;
97 smp_mb__before_atomic();
98 set_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags);
99 tc->t_last_expected_una = rm->m_ack_seq + 1;
100
101 rdsdebug("rm %p tcp nxt %u ack_seq %llu\n",
102 rm, rds_tcp_snd_nxt(tc),
103 (unsigned long long)rm->m_ack_seq);
104 }
105
106 if (hdr_off < sizeof(struct rds_header)) {
107 /* see rds_tcp_write_space() */
108 set_bit(SOCK_NOSPACE, &tc->t_sock->sk->sk_socket->flags);
109
110 ret = rds_tcp_sendmsg(tc->t_sock,
111 (void *)&rm->m_inc.i_hdr + hdr_off,
112 sizeof(rm->m_inc.i_hdr) - hdr_off);
113 if (ret < 0)
114 goto out;
115 done += ret;
116 if (hdr_off + done != sizeof(struct rds_header))
117 goto out;
118 }
119
120 more = rm->data.op_nents > 1 ? (MSG_MORE | MSG_SENDPAGE_NOTLAST) : 0;
121 while (sg < rm->data.op_nents) {
122 int flags = MSG_DONTWAIT | MSG_NOSIGNAL | more;
123
124 ret = tc->t_sock->ops->sendpage(tc->t_sock,
125 sg_page(&rm->data.op_sg[sg]),
126 rm->data.op_sg[sg].offset + off,
127 rm->data.op_sg[sg].length - off,
128 flags);
129 rdsdebug("tcp sendpage %p:%u:%u ret %d\n", (void *)sg_page(&rm->data.op_sg[sg]),
130 rm->data.op_sg[sg].offset + off, rm->data.op_sg[sg].length - off,
131 ret);
132 if (ret <= 0)
133 break;
134
135 off += ret;
136 done += ret;
137 if (off == rm->data.op_sg[sg].length) {
138 off = 0;
139 sg++;
140 }
141 if (sg == rm->data.op_nents - 1)
142 more = 0;
143 }
144
145out:
146 if (ret <= 0) {
147 /* write_space will hit after EAGAIN, all else fatal */
148 if (ret == -EAGAIN) {
149 rds_tcp_stats_inc(s_tcp_sndbuf_full);
150 ret = 0;
151 } else {
152 printk(KERN_WARNING "RDS/tcp: send to %pI4 "
153 "returned %d, disconnecting and reconnecting\n",
154 &conn->c_faddr, ret);
155 rds_conn_drop(conn);
156 }
157 }
158 if (done == 0)
159 done = ret;
160 return done;
161}
162
163/*
164 * rm->m_ack_seq is set to the tcp sequence number that corresponds to the
165 * last byte of the message, including the header. This means that the
166 * entire message has been received if rm->m_ack_seq is "before" the next
167 * unacked byte of the TCP sequence space. We have to do very careful
168 * wrapping 32bit comparisons here.
169 */
170static int rds_tcp_is_acked(struct rds_message *rm, uint64_t ack)
171{
172 if (!test_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags))
173 return 0;
174 return (__s32)((u32)rm->m_ack_seq - (u32)ack) < 0;
175}
176
177void rds_tcp_write_space(struct sock *sk)
178{
179 void (*write_space)(struct sock *sk);
180 struct rds_connection *conn;
181 struct rds_tcp_connection *tc;
182
183 read_lock(&sk->sk_callback_lock);
184 conn = sk->sk_user_data;
185 if (!conn) {
186 write_space = sk->sk_write_space;
187 goto out;
188 }
189
190 tc = conn->c_transport_data;
191 rdsdebug("write_space for tc %p\n", tc);
192 write_space = tc->t_orig_write_space;
193 rds_tcp_stats_inc(s_tcp_write_space_calls);
194
195 rdsdebug("tcp una %u\n", rds_tcp_snd_una(tc));
196 tc->t_last_seen_una = rds_tcp_snd_una(tc);
197 rds_send_drop_acked(conn, rds_tcp_snd_una(tc), rds_tcp_is_acked);
198
199 if ((atomic_read(&sk->sk_wmem_alloc) << 1) <= sk->sk_sndbuf)
200 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
201
202out:
203 read_unlock(&sk->sk_callback_lock);
204
205 /*
206 * write_space is only called when data leaves tcp's send queue if
207 * SOCK_NOSPACE is set. We set SOCK_NOSPACE every time we put
208 * data in tcp's send queue because we use write_space to parse the
209 * sequence numbers and notice that rds messages have been fully
210 * received.
211 *
212 * tcp's write_space clears SOCK_NOSPACE if the send queue has more
213 * than a certain amount of space. So we need to set it again *after*
214 * we call tcp's write_space or else we might only get called on the
215 * first of a series of incoming tcp acks.
216 */
217 write_space(sk);
218
219 if (sk->sk_socket)
220 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
221}
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#include <net/tcp.h>
36
37#include "rds_single_path.h"
38#include "rds.h"
39#include "tcp.h"
40
41static void rds_tcp_cork(struct socket *sock, int val)
42{
43 mm_segment_t oldfs;
44
45 oldfs = get_fs();
46 set_fs(KERNEL_DS);
47 sock->ops->setsockopt(sock, SOL_TCP, TCP_CORK, (char __user *)&val,
48 sizeof(val));
49 set_fs(oldfs);
50}
51
52void rds_tcp_xmit_path_prepare(struct rds_conn_path *cp)
53{
54 struct rds_tcp_connection *tc = cp->cp_transport_data;
55
56 rds_tcp_cork(tc->t_sock, 1);
57}
58
59void rds_tcp_xmit_path_complete(struct rds_conn_path *cp)
60{
61 struct rds_tcp_connection *tc = cp->cp_transport_data;
62
63 rds_tcp_cork(tc->t_sock, 0);
64}
65
66/* the core send_sem serializes this with other xmit and shutdown */
67static int rds_tcp_sendmsg(struct socket *sock, void *data, unsigned int len)
68{
69 struct kvec vec = {
70 .iov_base = data,
71 .iov_len = len,
72 };
73 struct msghdr msg = {
74 .msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL,
75 };
76
77 return kernel_sendmsg(sock, &msg, &vec, 1, vec.iov_len);
78}
79
80/* the core send_sem serializes this with other xmit and shutdown */
81int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm,
82 unsigned int hdr_off, unsigned int sg, unsigned int off)
83{
84 struct rds_conn_path *cp = rm->m_inc.i_conn_path;
85 struct rds_tcp_connection *tc = cp->cp_transport_data;
86 int done = 0;
87 int ret = 0;
88 int more;
89
90 if (hdr_off == 0) {
91 /*
92 * m_ack_seq is set to the sequence number of the last byte of
93 * header and data. see rds_tcp_is_acked().
94 */
95 tc->t_last_sent_nxt = rds_tcp_snd_nxt(tc);
96 rm->m_ack_seq = tc->t_last_sent_nxt +
97 sizeof(struct rds_header) +
98 be32_to_cpu(rm->m_inc.i_hdr.h_len) - 1;
99 smp_mb__before_atomic();
100 set_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags);
101 tc->t_last_expected_una = rm->m_ack_seq + 1;
102
103 if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags))
104 rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED;
105
106 rdsdebug("rm %p tcp nxt %u ack_seq %llu\n",
107 rm, rds_tcp_snd_nxt(tc),
108 (unsigned long long)rm->m_ack_seq);
109 }
110
111 if (hdr_off < sizeof(struct rds_header)) {
112 /* see rds_tcp_write_space() */
113 set_bit(SOCK_NOSPACE, &tc->t_sock->sk->sk_socket->flags);
114
115 ret = rds_tcp_sendmsg(tc->t_sock,
116 (void *)&rm->m_inc.i_hdr + hdr_off,
117 sizeof(rm->m_inc.i_hdr) - hdr_off);
118 if (ret < 0)
119 goto out;
120 done += ret;
121 if (hdr_off + done != sizeof(struct rds_header))
122 goto out;
123 }
124
125 more = rm->data.op_nents > 1 ? (MSG_MORE | MSG_SENDPAGE_NOTLAST) : 0;
126 while (sg < rm->data.op_nents) {
127 int flags = MSG_DONTWAIT | MSG_NOSIGNAL | more;
128
129 ret = tc->t_sock->ops->sendpage(tc->t_sock,
130 sg_page(&rm->data.op_sg[sg]),
131 rm->data.op_sg[sg].offset + off,
132 rm->data.op_sg[sg].length - off,
133 flags);
134 rdsdebug("tcp sendpage %p:%u:%u ret %d\n", (void *)sg_page(&rm->data.op_sg[sg]),
135 rm->data.op_sg[sg].offset + off, rm->data.op_sg[sg].length - off,
136 ret);
137 if (ret <= 0)
138 break;
139
140 off += ret;
141 done += ret;
142 if (off == rm->data.op_sg[sg].length) {
143 off = 0;
144 sg++;
145 }
146 if (sg == rm->data.op_nents - 1)
147 more = 0;
148 }
149
150out:
151 if (ret <= 0) {
152 /* write_space will hit after EAGAIN, all else fatal */
153 if (ret == -EAGAIN) {
154 rds_tcp_stats_inc(s_tcp_sndbuf_full);
155 ret = 0;
156 } else {
157 /* No need to disconnect/reconnect if path_drop
158 * has already been triggered, because, e.g., of
159 * an incoming RST.
160 */
161 if (rds_conn_path_up(cp)) {
162 pr_warn("RDS/tcp: send to %pI4 on cp [%d]"
163 "returned %d, "
164 "disconnecting and reconnecting\n",
165 &conn->c_faddr, cp->cp_index, ret);
166 rds_conn_path_drop(cp);
167 }
168 }
169 }
170 if (done == 0)
171 done = ret;
172 return done;
173}
174
175/*
176 * rm->m_ack_seq is set to the tcp sequence number that corresponds to the
177 * last byte of the message, including the header. This means that the
178 * entire message has been received if rm->m_ack_seq is "before" the next
179 * unacked byte of the TCP sequence space. We have to do very careful
180 * wrapping 32bit comparisons here.
181 */
182static int rds_tcp_is_acked(struct rds_message *rm, uint64_t ack)
183{
184 if (!test_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags))
185 return 0;
186 return (__s32)((u32)rm->m_ack_seq - (u32)ack) < 0;
187}
188
189void rds_tcp_write_space(struct sock *sk)
190{
191 void (*write_space)(struct sock *sk);
192 struct rds_conn_path *cp;
193 struct rds_tcp_connection *tc;
194
195 read_lock_bh(&sk->sk_callback_lock);
196 cp = sk->sk_user_data;
197 if (!cp) {
198 write_space = sk->sk_write_space;
199 goto out;
200 }
201
202 tc = cp->cp_transport_data;
203 rdsdebug("write_space for tc %p\n", tc);
204 write_space = tc->t_orig_write_space;
205 rds_tcp_stats_inc(s_tcp_write_space_calls);
206
207 rdsdebug("tcp una %u\n", rds_tcp_snd_una(tc));
208 tc->t_last_seen_una = rds_tcp_snd_una(tc);
209 rds_send_path_drop_acked(cp, rds_tcp_snd_una(tc), rds_tcp_is_acked);
210
211 if ((atomic_read(&sk->sk_wmem_alloc) << 1) <= sk->sk_sndbuf)
212 queue_delayed_work(rds_wq, &cp->cp_send_w, 0);
213
214out:
215 read_unlock_bh(&sk->sk_callback_lock);
216
217 /*
218 * write_space is only called when data leaves tcp's send queue if
219 * SOCK_NOSPACE is set. We set SOCK_NOSPACE every time we put
220 * data in tcp's send queue because we use write_space to parse the
221 * sequence numbers and notice that rds messages have been fully
222 * received.
223 *
224 * tcp's write_space clears SOCK_NOSPACE if the send queue has more
225 * than a certain amount of space. So we need to set it again *after*
226 * we call tcp's write_space or else we might only get called on the
227 * first of a series of incoming tcp acks.
228 */
229 write_space(sk);
230
231 if (sk->sk_socket)
232 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
233}