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