bridge: Have tx_bytes count headers like rx_bytes.
[linux-2.6.git] / net / rds / tcp_send.c
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
40 static 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
51 void 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
58 void 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 */
66 static 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 */
80 int 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
87         if (hdr_off == 0) {
88                 /*
89                  * m_ack_seq is set to the sequence number of the last byte of
90                  * header and data.  see rds_tcp_is_acked().
91                  */
92                 tc->t_last_sent_nxt = rds_tcp_snd_nxt(tc);
93                 rm->m_ack_seq = tc->t_last_sent_nxt +
94                                 sizeof(struct rds_header) +
95                                 be32_to_cpu(rm->m_inc.i_hdr.h_len) - 1;
96                 smp_mb__before_clear_bit();
97                 set_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags);
98                 tc->t_last_expected_una = rm->m_ack_seq + 1;
99
100                 rdsdebug("rm %p tcp nxt %u ack_seq %llu\n",
101                          rm, rds_tcp_snd_nxt(tc),
102                          (unsigned long long)rm->m_ack_seq);
103         }
104
105         if (hdr_off < sizeof(struct rds_header)) {
106                 /* see rds_tcp_write_space() */
107                 set_bit(SOCK_NOSPACE, &tc->t_sock->sk->sk_socket->flags);
108
109                 ret = rds_tcp_sendmsg(tc->t_sock,
110                                       (void *)&rm->m_inc.i_hdr + hdr_off,
111                                       sizeof(rm->m_inc.i_hdr) - hdr_off);
112                 if (ret < 0)
113                         goto out;
114                 done += ret;
115                 if (hdr_off + done != sizeof(struct rds_header))
116                         goto out;
117         }
118
119         while (sg < rm->data.op_nents) {
120                 ret = tc->t_sock->ops->sendpage(tc->t_sock,
121                                                 sg_page(&rm->data.op_sg[sg]),
122                                                 rm->data.op_sg[sg].offset + off,
123                                                 rm->data.op_sg[sg].length - off,
124                                                 MSG_DONTWAIT|MSG_NOSIGNAL);
125                 rdsdebug("tcp sendpage %p:%u:%u ret %d\n", (void *)sg_page(&rm->data.op_sg[sg]),
126                          rm->data.op_sg[sg].offset + off, rm->data.op_sg[sg].length - off,
127                          ret);
128                 if (ret <= 0)
129                         break;
130
131                 off += ret;
132                 done += ret;
133                 if (off == rm->data.op_sg[sg].length) {
134                         off = 0;
135                         sg++;
136                 }
137         }
138
139 out:
140         if (ret <= 0) {
141                 /* write_space will hit after EAGAIN, all else fatal */
142                 if (ret == -EAGAIN) {
143                         rds_tcp_stats_inc(s_tcp_sndbuf_full);
144                         ret = 0;
145                 } else {
146                         printk(KERN_WARNING "RDS/tcp: send to %pI4 "
147                                "returned %d, disconnecting and reconnecting\n",
148                                &conn->c_faddr, ret);
149                         rds_conn_drop(conn);
150                 }
151         }
152         if (done == 0)
153                 done = ret;
154         return done;
155 }
156
157 /*
158  * rm->m_ack_seq is set to the tcp sequence number that corresponds to the
159  * last byte of the message, including the header.  This means that the
160  * entire message has been received if rm->m_ack_seq is "before" the next
161  * unacked byte of the TCP sequence space.  We have to do very careful
162  * wrapping 32bit comparisons here.
163  */
164 static int rds_tcp_is_acked(struct rds_message *rm, uint64_t ack)
165 {
166         if (!test_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags))
167                 return 0;
168         return (__s32)((u32)rm->m_ack_seq - (u32)ack) < 0;
169 }
170
171 void rds_tcp_write_space(struct sock *sk)
172 {
173         void (*write_space)(struct sock *sk);
174         struct rds_connection *conn;
175         struct rds_tcp_connection *tc;
176
177         read_lock_bh(&sk->sk_callback_lock);
178         conn = sk->sk_user_data;
179         if (!conn) {
180                 write_space = sk->sk_write_space;
181                 goto out;
182         }
183
184         tc = conn->c_transport_data;
185         rdsdebug("write_space for tc %p\n", tc);
186         write_space = tc->t_orig_write_space;
187         rds_tcp_stats_inc(s_tcp_write_space_calls);
188
189         rdsdebug("tcp una %u\n", rds_tcp_snd_una(tc));
190         tc->t_last_seen_una = rds_tcp_snd_una(tc);
191         rds_send_drop_acked(conn, rds_tcp_snd_una(tc), rds_tcp_is_acked);
192
193         if ((atomic_read(&sk->sk_wmem_alloc) << 1) <= sk->sk_sndbuf)
194                 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
195
196 out:
197         read_unlock_bh(&sk->sk_callback_lock);
198
199         /*
200          * write_space is only called when data leaves tcp's send queue if
201          * SOCK_NOSPACE is set.  We set SOCK_NOSPACE every time we put
202          * data in tcp's send queue because we use write_space to parse the
203          * sequence numbers and notice that rds messages have been fully
204          * received.
205          *
206          * tcp's write_space clears SOCK_NOSPACE if the send queue has more
207          * than a certain amount of space. So we need to set it again *after*
208          * we call tcp's write_space or else we might only get called on the
209          * first of a series of incoming tcp acks.
210          */
211         write_space(sk);
212
213         if (sk->sk_socket)
214                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
215 }