cregit-Linux how code gets into the kernel

Release 4.11 net/rds/tcp_send.c

Directory: net/rds
/*
 * 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 <linux/kernel.h>
#include <linux/in.h>
#include <net/tcp.h>

#include "rds_single_path.h"
#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); }

Contributors

PersonTokensPropCommitsCommitProp
Andy Grover58100.00%1100.00%
Total58100.00%1100.00%


void rds_tcp_xmit_path_prepare(struct rds_conn_path *cp) { struct rds_tcp_connection *tc = cp->cp_transport_data; rds_tcp_cork(tc->t_sock, 1); }

Contributors

PersonTokensPropCommitsCommitProp
Andy Grover2382.14%150.00%
Sowmini Varadhan517.86%150.00%
Total28100.00%2100.00%


void rds_tcp_xmit_path_complete(struct rds_conn_path *cp) { struct rds_tcp_connection *tc = cp->cp_transport_data; rds_tcp_cork(tc->t_sock, 0); }

Contributors

PersonTokensPropCommitsCommitProp
Andy Grover2382.14%150.00%
Sowmini Varadhan517.86%150.00%
Total28100.00%2100.00%

/* the core send_sem serializes this with other xmit and shutdown */
static 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); }

Contributors

PersonTokensPropCommitsCommitProp
Andy Grover6496.97%133.33%
Joshua Houghton11.52%133.33%
Stephen Hemminger11.52%133.33%
Total66100.00%3100.00%

/* 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_conn_path *cp = rm->m_inc.i_conn_path; struct rds_tcp_connection *tc = cp->cp_transport_data; int done = 0; int ret = 0; int more; 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_atomic(); set_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags); tc->t_last_expected_una = rm->m_ack_seq + 1; if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED; 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; } more = rm->data.op_nents > 1 ? (MSG_MORE | MSG_SENDPAGE_NOTLAST) : 0; while (sg < rm->data.op_nents) { int flags = MSG_DONTWAIT | MSG_NOSIGNAL | more; ret = tc->t_sock->ops->sendpage(tc->t_sock, sg_page(&rm->data.op_sg[sg]), rm->data.op_sg[sg].offset + off, rm->data.op_sg[sg].length - off, flags); rdsdebug("tcp sendpage %p:%u:%u ret %d\n", (void *)sg_page(&rm->data.op_sg[sg]), rm->data.op_sg[sg].offset + off, rm->data.op_sg[sg].length - off, ret); if (ret <= 0) break; off += ret; done += ret; if (off == rm->data.op_sg[sg].length) { off = 0; sg++; } if (sg == rm->data.op_nents - 1) more = 0; } 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 { /* No need to disconnect/reconnect if path_drop * has already been triggered, because, e.g., of * an incoming RST. */ if (rds_conn_path_up(cp)) { pr_warn("RDS/tcp: send to %pI4 on cp [%d]" "returned %d, " "disconnecting and reconnecting\n", &conn->c_faddr, cp->cp_index, ret); rds_conn_path_drop(cp); } } } if (done == 0) done = ret; return done; }

Contributors

PersonTokensPropCommitsCommitProp
Andy Grover43580.71%337.50%
Sowmini Varadhan10218.92%337.50%
Peter Zijlstra10.19%112.50%
Joe Perches10.19%112.50%
Total539100.00%8100.00%

/* * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Andy Grover50100.00%1100.00%
Total50100.00%1100.00%


void rds_tcp_write_space(struct sock *sk) { void (*write_space)(struct sock *sk); struct rds_conn_path *cp; struct rds_tcp_connection *tc; read_lock_bh(&sk->sk_callback_lock); cp = sk->sk_user_data; if (!cp) { write_space = sk->sk_write_space; goto out; } tc = cp->cp_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_path_drop_acked(cp, rds_tcp_snd_una(tc), rds_tcp_is_acked); if ((atomic_read(&sk->sk_wmem_alloc) << 1) <= sk->sk_sndbuf) queue_delayed_work(rds_wq, &cp->cp_send_w, 0); out: read_unlock_bh(&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); }

Contributors

PersonTokensPropCommitsCommitProp
Andy Grover16993.37%360.00%
Sowmini Varadhan105.52%120.00%
Eric Dumazet21.10%120.00%
Total181100.00%5100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Andy Grover84186.52%531.25%
Sowmini Varadhan12512.86%637.50%
Eric Dumazet20.21%16.25%
Peter Zijlstra10.10%16.25%
Stephen Hemminger10.10%16.25%
Joshua Houghton10.10%16.25%
Joe Perches10.10%16.25%
Total972100.00%16100.00%
Directory: net/rds
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