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