Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
[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 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_cong_map(struct rds_connection *conn,
81                           struct rds_cong_map *map, unsigned long offset)
82 {
83         static struct rds_header rds_tcp_map_header = {
84                 .h_flags = RDS_FLAG_CONG_BITMAP,
85         };
86         struct rds_tcp_connection *tc = conn->c_transport_data;
87         unsigned long i;
88         int ret;
89         int copied = 0;
90
91         /* Some problem claims cpu_to_be32(constant) isn't a constant. */
92         rds_tcp_map_header.h_len = cpu_to_be32(RDS_CONG_MAP_BYTES);
93
94         if (offset < sizeof(struct rds_header)) {
95                 ret = rds_tcp_sendmsg(tc->t_sock,
96                                       (void *)&rds_tcp_map_header + offset,
97                                       sizeof(struct rds_header) - offset);
98                 if (ret <= 0)
99                         return ret;
100                 offset += ret;
101                 copied = ret;
102                 if (offset < sizeof(struct rds_header))
103                         return ret;
104         }
105
106         offset -= sizeof(struct rds_header);
107         i = offset / PAGE_SIZE;
108         offset = offset % PAGE_SIZE;
109         BUG_ON(i >= RDS_CONG_MAP_PAGES);
110
111         do {
112                 ret = tc->t_sock->ops->sendpage(tc->t_sock,
113                                         virt_to_page(map->m_page_addrs[i]),
114                                         offset, PAGE_SIZE - offset,
115                                         MSG_DONTWAIT);
116                 if (ret <= 0)
117                         break;
118                 copied += ret;
119                 offset += ret;
120                 if (offset == PAGE_SIZE) {
121                         offset = 0;
122                         i++;
123                 }
124         } while (i < RDS_CONG_MAP_PAGES);
125
126         return copied ? copied : ret;
127 }
128
129 /* the core send_sem serializes this with other xmit and shutdown */
130 int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm,
131                  unsigned int hdr_off, unsigned int sg, unsigned int off)
132 {
133         struct rds_tcp_connection *tc = conn->c_transport_data;
134         int done = 0;
135         int ret = 0;
136
137         if (hdr_off == 0) {
138                 /*
139                  * m_ack_seq is set to the sequence number of the last byte of
140                  * header and data.  see rds_tcp_is_acked().
141                  */
142                 tc->t_last_sent_nxt = rds_tcp_snd_nxt(tc);
143                 rm->m_ack_seq = tc->t_last_sent_nxt +
144                                 sizeof(struct rds_header) +
145                                 be32_to_cpu(rm->m_inc.i_hdr.h_len) - 1;
146                 smp_mb__before_clear_bit();
147                 set_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags);
148                 tc->t_last_expected_una = rm->m_ack_seq + 1;
149
150                 rdsdebug("rm %p tcp nxt %u ack_seq %llu\n",
151                          rm, rds_tcp_snd_nxt(tc),
152                          (unsigned long long)rm->m_ack_seq);
153         }
154
155         if (hdr_off < sizeof(struct rds_header)) {
156                 /* see rds_tcp_write_space() */
157                 set_bit(SOCK_NOSPACE, &tc->t_sock->sk->sk_socket->flags);
158
159                 ret = rds_tcp_sendmsg(tc->t_sock,
160                                       (void *)&rm->m_inc.i_hdr + hdr_off,
161                                       sizeof(rm->m_inc.i_hdr) - hdr_off);
162                 if (ret < 0)
163                         goto out;
164                 done += ret;
165                 if (hdr_off + done != sizeof(struct rds_header))
166                         goto out;
167         }
168
169         while (sg < rm->m_nents) {
170                 ret = tc->t_sock->ops->sendpage(tc->t_sock,
171                                                 sg_page(&rm->m_sg[sg]),
172                                                 rm->m_sg[sg].offset + off,
173                                                 rm->m_sg[sg].length - off,
174                                                 MSG_DONTWAIT|MSG_NOSIGNAL);
175                 rdsdebug("tcp sendpage %p:%u:%u ret %d\n", (void *)sg_page(&rm->m_sg[sg]),
176                          rm->m_sg[sg].offset + off, rm->m_sg[sg].length - off,
177                          ret);
178                 if (ret <= 0)
179                         break;
180
181                 off += ret;
182                 done += ret;
183                 if (off == rm->m_sg[sg].length) {
184                         off = 0;
185                         sg++;
186                 }
187         }
188
189 out:
190         if (ret <= 0) {
191                 /* write_space will hit after EAGAIN, all else fatal */
192                 if (ret == -EAGAIN) {
193                         rds_tcp_stats_inc(s_tcp_sndbuf_full);
194                         ret = 0;
195                 } else {
196                         printk(KERN_WARNING "RDS/tcp: send to %pI4 "
197                                "returned %d, disconnecting and reconnecting\n",
198                                &conn->c_faddr, ret);
199                         rds_conn_drop(conn);
200                 }
201         }
202         if (done == 0)
203                 done = ret;
204         return done;
205 }
206
207 /*
208  * rm->m_ack_seq is set to the tcp sequence number that corresponds to the
209  * last byte of the message, including the header.  This means that the
210  * entire message has been received if rm->m_ack_seq is "before" the next
211  * unacked byte of the TCP sequence space.  We have to do very careful
212  * wrapping 32bit comparisons here.
213  */
214 static int rds_tcp_is_acked(struct rds_message *rm, uint64_t ack)
215 {
216         if (!test_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags))
217                 return 0;
218         return (__s32)((u32)rm->m_ack_seq - (u32)ack) < 0;
219 }
220
221 void rds_tcp_write_space(struct sock *sk)
222 {
223         void (*write_space)(struct sock *sk);
224         struct rds_connection *conn;
225         struct rds_tcp_connection *tc;
226
227         read_lock(&sk->sk_callback_lock);
228         conn = sk->sk_user_data;
229         if (conn == NULL) {
230                 write_space = sk->sk_write_space;
231                 goto out;
232         }
233
234         tc = conn->c_transport_data;
235         rdsdebug("write_space for tc %p\n", tc);
236         write_space = tc->t_orig_write_space;
237         rds_tcp_stats_inc(s_tcp_write_space_calls);
238
239         rdsdebug("tcp una %u\n", rds_tcp_snd_una(tc));
240         tc->t_last_seen_una = rds_tcp_snd_una(tc);
241         rds_send_drop_acked(conn, rds_tcp_snd_una(tc), rds_tcp_is_acked);
242
243         queue_delayed_work(rds_wq, &conn->c_send_w, 0);
244 out:
245         read_unlock(&sk->sk_callback_lock);
246
247         /*
248          * write_space is only called when data leaves tcp's send queue if
249          * SOCK_NOSPACE is set.  We set SOCK_NOSPACE every time we put
250          * data in tcp's send queue because we use write_space to parse the
251          * sequence numbers and notice that rds messages have been fully
252          * received.
253          *
254          * tcp's write_space clears SOCK_NOSPACE if the send queue has more
255          * than a certain amount of space. So we need to set it again *after*
256          * we call tcp's write_space or else we might only get called on the
257          * first of a series of incoming tcp acks.
258          */
259         write_space(sk);
260
261         if (sk->sk_socket)
262                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
263 }