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 41 void 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 48 void 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 */ 56 static 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 */ 70 int 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 } 139 140 out: 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 */ 172 static 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 } 178 179 void 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(); 206 207 out: 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 } 227