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 if ((atomic_read(&sk->sk_wmem_alloc) << 1) <= sk->sk_sndbuf) 244 queue_delayed_work(rds_wq, &conn->c_send_w, 0); 245 246 out: 247 read_unlock(&sk->sk_callback_lock); 248 249 /* 250 * write_space is only called when data leaves tcp's send queue if 251 * SOCK_NOSPACE is set. We set SOCK_NOSPACE every time we put 252 * data in tcp's send queue because we use write_space to parse the 253 * sequence numbers and notice that rds messages have been fully 254 * received. 255 * 256 * tcp's write_space clears SOCK_NOSPACE if the send queue has more 257 * than a certain amount of space. So we need to set it again *after* 258 * we call tcp's write_space or else we might only get called on the 259 * first of a series of incoming tcp acks. 260 */ 261 write_space(sk); 262 263 if (sk->sk_socket) 264 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 265 } 266