From 70041088e3b976627ba9a183b812f39ef8a9ba0e Mon Sep 17 00:00:00 2001 From: Andy Grover Date: Fri, 21 Aug 2009 12:28:31 +0000 Subject: RDS: Add TCP transport to RDS This code allows RDS to be tunneled over a TCP connection. RDMA operations are disabled when using TCP transport, but this frees RDS from the IB/RDMA stack dependency, and allows it to be used with standard Ethernet adapters, or in a VM. Signed-off-by: Andy Grover Signed-off-by: David S. Miller --- net/rds/tcp_send.c | 263 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 263 insertions(+) create mode 100644 net/rds/tcp_send.c (limited to 'net/rds/tcp_send.c') diff --git a/net/rds/tcp_send.c b/net/rds/tcp_send.c new file mode 100644 index 000000000000..ab545e0cd5d6 --- /dev/null +++ b/net/rds/tcp_send.c @@ -0,0 +1,263 @@ +/* + * Copyright (c) 2006 Oracle. All rights reserved. + * + * This software is available to you under a choice of one of two + * licenses. You may choose to be licensed under the terms of the GNU + * General Public License (GPL) Version 2, available from the file + * COPYING in the main directory of this source tree, or the + * OpenIB.org BSD license below: + * + * Redistribution and use in source and binary forms, with or + * without modification, are permitted provided that the following + * conditions are met: + * + * - Redistributions of source code must retain the above + * copyright notice, this list of conditions and the following + * disclaimer. + * + * - Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following + * disclaimer in the documentation and/or other materials + * provided with the distribution. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + * + */ +#include +#include +#include + +#include "rds.h" +#include "tcp.h" + +static void rds_tcp_cork(struct socket *sock, int val) +{ + mm_segment_t oldfs; + + oldfs = get_fs(); + set_fs(KERNEL_DS); + sock->ops->setsockopt(sock, SOL_TCP, TCP_CORK, (char __user *)&val, + sizeof(val)); + set_fs(oldfs); +} + +void rds_tcp_xmit_prepare(struct rds_connection *conn) +{ + struct rds_tcp_connection *tc = conn->c_transport_data; + + rds_tcp_cork(tc->t_sock, 1); +} + +void rds_tcp_xmit_complete(struct rds_connection *conn) +{ + struct rds_tcp_connection *tc = conn->c_transport_data; + + rds_tcp_cork(tc->t_sock, 0); +} + +/* the core send_sem serializes this with other xmit and shutdown */ +int rds_tcp_sendmsg(struct socket *sock, void *data, unsigned int len) +{ + struct kvec vec = { + .iov_base = data, + .iov_len = len, + }; + struct msghdr msg = { + .msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL, + }; + + return kernel_sendmsg(sock, &msg, &vec, 1, vec.iov_len); +} + +/* the core send_sem serializes this with other xmit and shutdown */ +int rds_tcp_xmit_cong_map(struct rds_connection *conn, + struct rds_cong_map *map, unsigned long offset) +{ + static struct rds_header rds_tcp_map_header = { + .h_flags = RDS_FLAG_CONG_BITMAP, + }; + struct rds_tcp_connection *tc = conn->c_transport_data; + unsigned long i; + int ret; + int copied = 0; + + /* Some problem claims cpu_to_be32(constant) isn't a constant. */ + rds_tcp_map_header.h_len = cpu_to_be32(RDS_CONG_MAP_BYTES); + + if (offset < sizeof(struct rds_header)) { + ret = rds_tcp_sendmsg(tc->t_sock, + (void *)&rds_tcp_map_header + offset, + sizeof(struct rds_header) - offset); + if (ret <= 0) + return ret; + offset += ret; + copied = ret; + if (offset < sizeof(struct rds_header)) + return ret; + } + + offset -= sizeof(struct rds_header); + i = offset / PAGE_SIZE; + offset = offset % PAGE_SIZE; + BUG_ON(i >= RDS_CONG_MAP_PAGES); + + do { + ret = tc->t_sock->ops->sendpage(tc->t_sock, + virt_to_page(map->m_page_addrs[i]), + offset, PAGE_SIZE - offset, + MSG_DONTWAIT); + if (ret <= 0) + break; + copied += ret; + offset += ret; + if (offset == PAGE_SIZE) { + offset = 0; + i++; + } + } while (i < RDS_CONG_MAP_PAGES); + + return copied ? copied : ret; +} + +/* the core send_sem serializes this with other xmit and shutdown */ +int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm, + unsigned int hdr_off, unsigned int sg, unsigned int off) +{ + struct rds_tcp_connection *tc = conn->c_transport_data; + int done = 0; + int ret = 0; + + if (hdr_off == 0) { + /* + * m_ack_seq is set to the sequence number of the last byte of + * header and data. see rds_tcp_is_acked(). + */ + tc->t_last_sent_nxt = rds_tcp_snd_nxt(tc); + rm->m_ack_seq = tc->t_last_sent_nxt + + sizeof(struct rds_header) + + be32_to_cpu(rm->m_inc.i_hdr.h_len) - 1; + smp_mb__before_clear_bit(); + set_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags); + tc->t_last_expected_una = rm->m_ack_seq + 1; + + rdsdebug("rm %p tcp nxt %u ack_seq %llu\n", + rm, rds_tcp_snd_nxt(tc), + (unsigned long long)rm->m_ack_seq); + } + + if (hdr_off < sizeof(struct rds_header)) { + /* see rds_tcp_write_space() */ + set_bit(SOCK_NOSPACE, &tc->t_sock->sk->sk_socket->flags); + + ret = rds_tcp_sendmsg(tc->t_sock, + (void *)&rm->m_inc.i_hdr + hdr_off, + sizeof(rm->m_inc.i_hdr) - hdr_off); + if (ret < 0) + goto out; + done += ret; + if (hdr_off + done != sizeof(struct rds_header)) + goto out; + } + + while (sg < rm->m_nents) { + ret = tc->t_sock->ops->sendpage(tc->t_sock, + sg_page(&rm->m_sg[sg]), + rm->m_sg[sg].offset + off, + rm->m_sg[sg].length - off, + MSG_DONTWAIT|MSG_NOSIGNAL); + rdsdebug("tcp sendpage %p:%u:%u ret %d\n", (void *)sg_page(&rm->m_sg[sg]), + rm->m_sg[sg].offset + off, rm->m_sg[sg].length - off, + ret); + if (ret <= 0) + break; + + off += ret; + done += ret; + if (off == rm->m_sg[sg].length) { + off = 0; + sg++; + } + } + +out: + if (ret <= 0) { + /* write_space will hit after EAGAIN, all else fatal */ + if (ret == -EAGAIN) { + rds_tcp_stats_inc(s_tcp_sndbuf_full); + ret = 0; + } else { + printk(KERN_WARNING "RDS/tcp: send to %u.%u.%u.%u " + "returned %d, disconnecting and reconnecting\n", + NIPQUAD(conn->c_faddr), ret); + rds_conn_drop(conn); + } + } + if (done == 0) + done = ret; + return done; +} + +/* + * rm->m_ack_seq is set to the tcp sequence number that corresponds to the + * last byte of the message, including the header. This means that the + * entire message has been received if rm->m_ack_seq is "before" the next + * unacked byte of the TCP sequence space. We have to do very careful + * wrapping 32bit comparisons here. + */ +static int rds_tcp_is_acked(struct rds_message *rm, uint64_t ack) +{ + if (!test_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags)) + return 0; + return (__s32)((u32)rm->m_ack_seq - (u32)ack) < 0; +} + +void rds_tcp_write_space(struct sock *sk) +{ + void (*write_space)(struct sock *sk); + struct rds_connection *conn; + struct rds_tcp_connection *tc; + + read_lock(&sk->sk_callback_lock); + conn = sk->sk_user_data; + if (conn == NULL) { + write_space = sk->sk_write_space; + goto out; + } + + tc = conn->c_transport_data; + rdsdebug("write_space for tc %p\n", tc); + write_space = tc->t_orig_write_space; + rds_tcp_stats_inc(s_tcp_write_space_calls); + + rdsdebug("tcp una %u\n", rds_tcp_snd_una(tc)); + tc->t_last_seen_una = rds_tcp_snd_una(tc); + rds_send_drop_acked(conn, rds_tcp_snd_una(tc), rds_tcp_is_acked); + + queue_delayed_work(rds_wq, &conn->c_send_w, 0); +out: + read_unlock(&sk->sk_callback_lock); + + /* + * write_space is only called when data leaves tcp's send queue if + * SOCK_NOSPACE is set. We set SOCK_NOSPACE every time we put + * data in tcp's send queue because we use write_space to parse the + * sequence numbers and notice that rds messages have been fully + * received. + * + * tcp's write_space clears SOCK_NOSPACE if the send queue has more + * than a certain amount of space. So we need to set it again *after* + * we call tcp's write_space or else we might only get called on the + * first of a series of incoming tcp acks. + */ + write_space(sk); + + if (sk->sk_socket) + set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); +} -- cgit v1.2.3-58-ga151