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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, 2017 Oracle and/or its affiliates. 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
41void rds_tcp_xmit_path_prepare(struct rds_conn_path *cp)
42{
43 struct rds_tcp_connection *tc = cp->cp_transport_data;
44
45 tcp_sock_set_cork(tc->t_sock->sk, true);
46}
47
48void rds_tcp_xmit_path_complete(struct rds_conn_path *cp)
49{
50 struct rds_tcp_connection *tc = cp->cp_transport_data;
51
52 tcp_sock_set_cork(tc->t_sock->sk, false);
53}
54
55/* the core send_sem serializes this with other xmit and shutdown */
56static int rds_tcp_sendmsg(struct socket *sock, void *data, unsigned int len)
57{
58 struct kvec vec = {
59 .iov_base = data,
60 .iov_len = len,
61 };
62 struct msghdr msg = {
63 .msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL,
64 };
65
66 return kernel_sendmsg(sock, &msg, &vec, 1, vec.iov_len);
67}
68
69/* the core send_sem serializes this with other xmit and shutdown */
70int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm,
71 unsigned int hdr_off, unsigned int sg, unsigned int off)
72{
73 struct rds_conn_path *cp = rm->m_inc.i_conn_path;
74 struct rds_tcp_connection *tc = cp->cp_transport_data;
75 struct msghdr msg = {};
76 struct bio_vec bvec;
77 int done = 0;
78 int ret = 0;
79
80 if (hdr_off == 0) {
81 /*
82 * m_ack_seq is set to the sequence number of the last byte of
83 * header and data. see rds_tcp_is_acked().
84 */
85 tc->t_last_sent_nxt = rds_tcp_write_seq(tc);
86 rm->m_ack_seq = tc->t_last_sent_nxt +
87 sizeof(struct rds_header) +
88 be32_to_cpu(rm->m_inc.i_hdr.h_len) - 1;
89 smp_mb__before_atomic();
90 set_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags);
91 tc->t_last_expected_una = rm->m_ack_seq + 1;
92
93 if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags))
94 rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED;
95
96 rdsdebug("rm %p tcp nxt %u ack_seq %llu\n",
97 rm, rds_tcp_write_seq(tc),
98 (unsigned long long)rm->m_ack_seq);
99 }
100
101 if (hdr_off < sizeof(struct rds_header)) {
102 /* see rds_tcp_write_space() */
103 set_bit(SOCK_NOSPACE, &tc->t_sock->sk->sk_socket->flags);
104
105 ret = rds_tcp_sendmsg(tc->t_sock,
106 (void *)&rm->m_inc.i_hdr + hdr_off,
107 sizeof(rm->m_inc.i_hdr) - hdr_off);
108 if (ret < 0)
109 goto out;
110 done += ret;
111 if (hdr_off + done != sizeof(struct rds_header))
112 goto out;
113 }
114
115 while (sg < rm->data.op_nents) {
116 msg.msg_flags = MSG_SPLICE_PAGES | MSG_DONTWAIT | MSG_NOSIGNAL;
117 if (sg + 1 < rm->data.op_nents)
118 msg.msg_flags |= MSG_MORE;
119
120 bvec_set_page(&bvec, sg_page(&rm->data.op_sg[sg]),
121 rm->data.op_sg[sg].length - off,
122 rm->data.op_sg[sg].offset + off);
123 iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1,
124 rm->data.op_sg[sg].length - off);
125 ret = sock_sendmsg(tc->t_sock, &msg);
126 rdsdebug("tcp sendpage %p:%u:%u ret %d\n", (void *)sg_page(&rm->data.op_sg[sg]),
127 rm->data.op_sg[sg].offset + off, rm->data.op_sg[sg].length - off,
128 ret);
129 if (ret <= 0)
130 break;
131
132 off += ret;
133 done += ret;
134 if (off == rm->data.op_sg[sg].length) {
135 off = 0;
136 sg++;
137 }
138 }
139
140out:
141 if (ret <= 0) {
142 /* write_space will hit after EAGAIN, all else fatal */
143 if (ret == -EAGAIN) {
144 rds_tcp_stats_inc(s_tcp_sndbuf_full);
145 ret = 0;
146 } else {
147 /* No need to disconnect/reconnect if path_drop
148 * has already been triggered, because, e.g., of
149 * an incoming RST.
150 */
151 if (rds_conn_path_up(cp)) {
152 pr_warn("RDS/tcp: send to %pI6c on cp [%d]"
153 "returned %d, "
154 "disconnecting and reconnecting\n",
155 &conn->c_faddr, cp->cp_index, ret);
156 rds_conn_path_drop(cp, false);
157 }
158 }
159 }
160 if (done == 0)
161 done = ret;
162 return done;
163}
164
165/*
166 * rm->m_ack_seq is set to the tcp sequence number that corresponds to the
167 * last byte of the message, including the header. This means that the
168 * entire message has been received if rm->m_ack_seq is "before" the next
169 * unacked byte of the TCP sequence space. We have to do very careful
170 * wrapping 32bit comparisons here.
171 */
172static int rds_tcp_is_acked(struct rds_message *rm, uint64_t ack)
173{
174 if (!test_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags))
175 return 0;
176 return (__s32)((u32)rm->m_ack_seq - (u32)ack) < 0;
177}
178
179void rds_tcp_write_space(struct sock *sk)
180{
181 void (*write_space)(struct sock *sk);
182 struct rds_conn_path *cp;
183 struct rds_tcp_connection *tc;
184
185 read_lock_bh(&sk->sk_callback_lock);
186 cp = sk->sk_user_data;
187 if (!cp) {
188 write_space = sk->sk_write_space;
189 goto out;
190 }
191
192 tc = cp->cp_transport_data;
193 rdsdebug("write_space for tc %p\n", tc);
194 write_space = tc->t_orig_write_space;
195 rds_tcp_stats_inc(s_tcp_write_space_calls);
196
197 rdsdebug("tcp una %u\n", rds_tcp_snd_una(tc));
198 tc->t_last_seen_una = rds_tcp_snd_una(tc);
199 rds_send_path_drop_acked(cp, rds_tcp_snd_una(tc), rds_tcp_is_acked);
200
201 rcu_read_lock();
202 if ((refcount_read(&sk->sk_wmem_alloc) << 1) <= sk->sk_sndbuf &&
203 !rds_destroy_pending(cp->cp_conn))
204 queue_delayed_work(rds_wq, &cp->cp_send_w, 0);
205 rcu_read_unlock();
206
207out:
208 read_unlock_bh(&sk->sk_callback_lock);
209
210 /*
211 * write_space is only called when data leaves tcp's send queue if
212 * SOCK_NOSPACE is set. We set SOCK_NOSPACE every time we put
213 * data in tcp's send queue because we use write_space to parse the
214 * sequence numbers and notice that rds messages have been fully
215 * received.
216 *
217 * tcp's write_space clears SOCK_NOSPACE if the send queue has more
218 * than a certain amount of space. So we need to set it again *after*
219 * we call tcp's write_space or else we might only get called on the
220 * first of a series of incoming tcp acks.
221 */
222 write_space(sk);
223
224 if (sk->sk_socket)
225 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
226}