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 mm_segment_t oldfs; 44 45 oldfs = get_fs(); 46 set_fs(KERNEL_DS); 47 sock->ops->setsockopt(sock, SOL_TCP, TCP_CORK, (char __user *)&val, 48 sizeof(val)); 49 set_fs(oldfs); 50 } 51 52 void rds_tcp_xmit_path_prepare(struct rds_conn_path *cp) 53 { 54 struct rds_tcp_connection *tc = cp->cp_transport_data; 55 56 rds_tcp_cork(tc->t_sock, 1); 57 } 58 59 void rds_tcp_xmit_path_complete(struct rds_conn_path *cp) 60 { 61 struct rds_tcp_connection *tc = cp->cp_transport_data; 62 63 rds_tcp_cork(tc->t_sock, 0); 64 } 65 66 /* the core send_sem serializes this with other xmit and shutdown */ 67 static int rds_tcp_sendmsg(struct socket *sock, void *data, unsigned int len) 68 { 69 struct kvec vec = { 70 .iov_base = data, 71 .iov_len = len, 72 }; 73 struct msghdr msg = { 74 .msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL, 75 }; 76 77 return kernel_sendmsg(sock, &msg, &vec, 1, vec.iov_len); 78 } 79 80 /* the core send_sem serializes this with other xmit and shutdown */ 81 int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm, 82 unsigned int hdr_off, unsigned int sg, unsigned int off) 83 { 84 struct rds_conn_path *cp = rm->m_inc.i_conn_path; 85 struct rds_tcp_connection *tc = cp->cp_transport_data; 86 int done = 0; 87 int ret = 0; 88 int more; 89 90 if (hdr_off == 0) { 91 /* 92 * m_ack_seq is set to the sequence number of the last byte of 93 * header and data. see rds_tcp_is_acked(). 94 */ 95 tc->t_last_sent_nxt = rds_tcp_snd_nxt(tc); 96 rm->m_ack_seq = tc->t_last_sent_nxt + 97 sizeof(struct rds_header) + 98 be32_to_cpu(rm->m_inc.i_hdr.h_len) - 1; 99 smp_mb__before_atomic(); 100 set_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags); 101 tc->t_last_expected_una = rm->m_ack_seq + 1; 102 103 rdsdebug("rm %p tcp nxt %u ack_seq %llu\n", 104 rm, rds_tcp_snd_nxt(tc), 105 (unsigned long long)rm->m_ack_seq); 106 } 107 108 if (hdr_off < sizeof(struct rds_header)) { 109 /* see rds_tcp_write_space() */ 110 set_bit(SOCK_NOSPACE, &tc->t_sock->sk->sk_socket->flags); 111 112 ret = rds_tcp_sendmsg(tc->t_sock, 113 (void *)&rm->m_inc.i_hdr + hdr_off, 114 sizeof(rm->m_inc.i_hdr) - hdr_off); 115 if (ret < 0) 116 goto out; 117 done += ret; 118 if (hdr_off + done != sizeof(struct rds_header)) 119 goto out; 120 } 121 122 more = rm->data.op_nents > 1 ? (MSG_MORE | MSG_SENDPAGE_NOTLAST) : 0; 123 while (sg < rm->data.op_nents) { 124 int flags = MSG_DONTWAIT | MSG_NOSIGNAL | more; 125 126 ret = tc->t_sock->ops->sendpage(tc->t_sock, 127 sg_page(&rm->data.op_sg[sg]), 128 rm->data.op_sg[sg].offset + off, 129 rm->data.op_sg[sg].length - off, 130 flags); 131 rdsdebug("tcp sendpage %p:%u:%u ret %d\n", (void *)sg_page(&rm->data.op_sg[sg]), 132 rm->data.op_sg[sg].offset + off, rm->data.op_sg[sg].length - off, 133 ret); 134 if (ret <= 0) 135 break; 136 137 off += ret; 138 done += ret; 139 if (off == rm->data.op_sg[sg].length) { 140 off = 0; 141 sg++; 142 } 143 if (sg == rm->data.op_nents - 1) 144 more = 0; 145 } 146 147 out: 148 if (ret <= 0) { 149 /* write_space will hit after EAGAIN, all else fatal */ 150 if (ret == -EAGAIN) { 151 rds_tcp_stats_inc(s_tcp_sndbuf_full); 152 ret = 0; 153 } else { 154 /* No need to disconnect/reconnect if path_drop 155 * has already been triggered, because, e.g., of 156 * an incoming RST. 157 */ 158 if (rds_conn_path_up(cp)) { 159 pr_warn("RDS/tcp: send to %pI4 on cp [%d]" 160 "returned %d, " 161 "disconnecting and reconnecting\n", 162 &conn->c_faddr, cp->cp_index, ret); 163 rds_conn_path_drop(cp); 164 } 165 } 166 } 167 if (done == 0) 168 done = ret; 169 return done; 170 } 171 172 /* 173 * rm->m_ack_seq is set to the tcp sequence number that corresponds to the 174 * last byte of the message, including the header. This means that the 175 * entire message has been received if rm->m_ack_seq is "before" the next 176 * unacked byte of the TCP sequence space. We have to do very careful 177 * wrapping 32bit comparisons here. 178 */ 179 static int rds_tcp_is_acked(struct rds_message *rm, uint64_t ack) 180 { 181 if (!test_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags)) 182 return 0; 183 return (__s32)((u32)rm->m_ack_seq - (u32)ack) < 0; 184 } 185 186 void rds_tcp_write_space(struct sock *sk) 187 { 188 void (*write_space)(struct sock *sk); 189 struct rds_conn_path *cp; 190 struct rds_tcp_connection *tc; 191 192 read_lock_bh(&sk->sk_callback_lock); 193 cp = sk->sk_user_data; 194 if (!cp) { 195 write_space = sk->sk_write_space; 196 goto out; 197 } 198 199 tc = cp->cp_transport_data; 200 rdsdebug("write_space for tc %p\n", tc); 201 write_space = tc->t_orig_write_space; 202 rds_tcp_stats_inc(s_tcp_write_space_calls); 203 204 rdsdebug("tcp una %u\n", rds_tcp_snd_una(tc)); 205 tc->t_last_seen_una = rds_tcp_snd_una(tc); 206 rds_send_path_drop_acked(cp, rds_tcp_snd_una(tc), rds_tcp_is_acked); 207 208 if ((atomic_read(&sk->sk_wmem_alloc) << 1) <= sk->sk_sndbuf) 209 queue_delayed_work(rds_wq, &cp->cp_send_w, 0); 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