231 lines
6.8 KiB
C
231 lines
6.8 KiB
C
/*
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* Copyright (c) 2006, 2017 Oracle and/or its affiliates. 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_single_path.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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kernel_setsockopt(sock, SOL_TCP, TCP_CORK, (void *)&val, sizeof(val));
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}
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void rds_tcp_xmit_path_prepare(struct rds_conn_path *cp)
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{
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struct rds_tcp_connection *tc = cp->cp_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_path_complete(struct rds_conn_path *cp)
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{
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struct rds_tcp_connection *tc = cp->cp_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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static 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(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_conn_path *cp = rm->m_inc.i_conn_path;
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struct rds_tcp_connection *tc = cp->cp_transport_data;
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int done = 0;
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int ret = 0;
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int more;
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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_write_seq(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_atomic();
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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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if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags))
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rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED;
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rdsdebug("rm %p tcp nxt %u ack_seq %llu\n",
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rm, rds_tcp_write_seq(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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more = rm->data.op_nents > 1 ? (MSG_MORE | MSG_SENDPAGE_NOTLAST) : 0;
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while (sg < rm->data.op_nents) {
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int flags = MSG_DONTWAIT | MSG_NOSIGNAL | more;
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ret = tc->t_sock->ops->sendpage(tc->t_sock,
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sg_page(&rm->data.op_sg[sg]),
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rm->data.op_sg[sg].offset + off,
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rm->data.op_sg[sg].length - off,
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flags);
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rdsdebug("tcp sendpage %p:%u:%u ret %d\n", (void *)sg_page(&rm->data.op_sg[sg]),
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rm->data.op_sg[sg].offset + off, rm->data.op_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->data.op_sg[sg].length) {
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off = 0;
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sg++;
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}
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if (sg == rm->data.op_nents - 1)
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more = 0;
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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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/* No need to disconnect/reconnect if path_drop
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* has already been triggered, because, e.g., of
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* an incoming RST.
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*/
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if (rds_conn_path_up(cp)) {
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pr_warn("RDS/tcp: send to %pI6c on cp [%d]"
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"returned %d, "
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"disconnecting and reconnecting\n",
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&conn->c_faddr, cp->cp_index, ret);
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rds_conn_path_drop(cp, false);
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}
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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_conn_path *cp;
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struct rds_tcp_connection *tc;
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read_lock_bh(&sk->sk_callback_lock);
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cp = sk->sk_user_data;
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if (!cp) {
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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 = cp->cp_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_path_drop_acked(cp, rds_tcp_snd_una(tc), rds_tcp_is_acked);
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rcu_read_lock();
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if ((refcount_read(&sk->sk_wmem_alloc) << 1) <= sk->sk_sndbuf &&
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!rds_destroy_pending(cp->cp_conn))
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queue_delayed_work(rds_wq, &cp->cp_send_w, 0);
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rcu_read_unlock();
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out:
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read_unlock_bh(&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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