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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312/* * Copyright (c) 2006, 2018 Oracle and/or its affiliates. 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/random.h>#include <linux/export.h>
#include "rds.h"
/* * All of connection management is simplified by serializing it through * work queues that execute in a connection managing thread. * * TCP wants to send acks through sendpage() in response to data_ready(), * but it needs a process context to do so. * * The receive paths need to allocate but can't drop packets (!) so we have * a thread around to block allocating if the receive fast path sees an * allocation failure. */
/* Grand Unified Theory of connection life cycle: * At any point in time, the connection can be in one of these states: * DOWN, CONNECTING, UP, DISCONNECTING, ERROR * * The following transitions are possible: * ANY -> ERROR * UP -> DISCONNECTING * ERROR -> DISCONNECTING * DISCONNECTING -> DOWN * DOWN -> CONNECTING * CONNECTING -> UP * * Transition to state DISCONNECTING/DOWN: * - Inside the shutdown worker; synchronizes with xmit path * through RDS_IN_XMIT, and with connection management callbacks * via c_cm_lock. * * For receive callbacks, we rely on the underlying transport * (TCP, IB/RDMA) to provide the necessary synchronisation. */struct workqueue_struct *rds_wq;EXPORT_SYMBOL_GPL(rds_wq);
void rds_connect_path_complete(struct rds_conn_path *cp, int curr){ if (!rds_conn_path_transition(cp, curr, RDS_CONN_UP)) { printk(KERN_WARNING "%s: Cannot transition to state UP, " "current state is %d\n", __func__, atomic_read(&cp->cp_state)); rds_conn_path_drop(cp, false); return; }
rdsdebug("conn %p for %pI6c to %pI6c complete\n", cp->cp_conn, &cp->cp_conn->c_laddr, &cp->cp_conn->c_faddr);
cp->cp_reconnect_jiffies = 0; set_bit(0, &cp->cp_conn->c_map_queued); rcu_read_lock(); if (!rds_destroy_pending(cp->cp_conn)) { queue_delayed_work(cp->cp_wq, &cp->cp_send_w, 0); queue_delayed_work(cp->cp_wq, &cp->cp_recv_w, 0); } rcu_read_unlock(); cp->cp_conn->c_proposed_version = RDS_PROTOCOL_VERSION;}EXPORT_SYMBOL_GPL(rds_connect_path_complete);
void rds_connect_complete(struct rds_connection *conn){ rds_connect_path_complete(&conn->c_path[0], RDS_CONN_CONNECTING);}EXPORT_SYMBOL_GPL(rds_connect_complete);
/* * This random exponential backoff is relied on to eventually resolve racing * connects. * * If connect attempts race then both parties drop both connections and come * here to wait for a random amount of time before trying again. Eventually * the backoff range will be so much greater than the time it takes to * establish a connection that one of the pair will establish the connection * before the other's random delay fires. * * Connection attempts that arrive while a connection is already established * are also considered to be racing connects. This lets a connection from * a rebooted machine replace an existing stale connection before the transport * notices that the connection has failed. * * We should *always* start with a random backoff; otherwise a broken connection * will always take several iterations to be re-established. */void rds_queue_reconnect(struct rds_conn_path *cp){ unsigned long rand; struct rds_connection *conn = cp->cp_conn;
rdsdebug("conn %p for %pI6c to %pI6c reconnect jiffies %lu\n", conn, &conn->c_laddr, &conn->c_faddr, cp->cp_reconnect_jiffies);
/* let peer with smaller addr initiate reconnect, to avoid duels */ if (conn->c_trans->t_type == RDS_TRANS_TCP && rds_addr_cmp(&conn->c_laddr, &conn->c_faddr) >= 0) return;
set_bit(RDS_RECONNECT_PENDING, &cp->cp_flags); if (cp->cp_reconnect_jiffies == 0) { cp->cp_reconnect_jiffies = rds_sysctl_reconnect_min_jiffies; rcu_read_lock(); if (!rds_destroy_pending(cp->cp_conn)) queue_delayed_work(cp->cp_wq, &cp->cp_conn_w, 0); rcu_read_unlock(); return; }
get_random_bytes(&rand, sizeof(rand)); rdsdebug("%lu delay %lu ceil conn %p for %pI6c -> %pI6c\n", rand % cp->cp_reconnect_jiffies, cp->cp_reconnect_jiffies, conn, &conn->c_laddr, &conn->c_faddr); rcu_read_lock(); if (!rds_destroy_pending(cp->cp_conn)) queue_delayed_work(cp->cp_wq, &cp->cp_conn_w, rand % cp->cp_reconnect_jiffies); rcu_read_unlock();
cp->cp_reconnect_jiffies = min(cp->cp_reconnect_jiffies * 2, rds_sysctl_reconnect_max_jiffies);}
void rds_connect_worker(struct work_struct *work){ struct rds_conn_path *cp = container_of(work, struct rds_conn_path, cp_conn_w.work); struct rds_connection *conn = cp->cp_conn; int ret;
if (cp->cp_index > 0 && rds_addr_cmp(&cp->cp_conn->c_laddr, &cp->cp_conn->c_faddr) >= 0) return; clear_bit(RDS_RECONNECT_PENDING, &cp->cp_flags); ret = rds_conn_path_transition(cp, RDS_CONN_DOWN, RDS_CONN_CONNECTING); if (ret) { ret = conn->c_trans->conn_path_connect(cp); rdsdebug("conn %p for %pI6c to %pI6c dispatched, ret %d\n", conn, &conn->c_laddr, &conn->c_faddr, ret);
if (ret) { if (rds_conn_path_transition(cp, RDS_CONN_CONNECTING, RDS_CONN_DOWN)) rds_queue_reconnect(cp); else rds_conn_path_error(cp, "connect failed\n"); } }}
void rds_send_worker(struct work_struct *work){ struct rds_conn_path *cp = container_of(work, struct rds_conn_path, cp_send_w.work); int ret;
if (rds_conn_path_state(cp) == RDS_CONN_UP) { clear_bit(RDS_LL_SEND_FULL, &cp->cp_flags); ret = rds_send_xmit(cp); cond_resched(); rdsdebug("conn %p ret %d\n", cp->cp_conn, ret); switch (ret) { case -EAGAIN: rds_stats_inc(s_send_immediate_retry); queue_delayed_work(cp->cp_wq, &cp->cp_send_w, 0); break; case -ENOMEM: rds_stats_inc(s_send_delayed_retry); queue_delayed_work(cp->cp_wq, &cp->cp_send_w, 2); break; default: break; } }}
void rds_recv_worker(struct work_struct *work){ struct rds_conn_path *cp = container_of(work, struct rds_conn_path, cp_recv_w.work); int ret;
if (rds_conn_path_state(cp) == RDS_CONN_UP) { ret = cp->cp_conn->c_trans->recv_path(cp); rdsdebug("conn %p ret %d\n", cp->cp_conn, ret); switch (ret) { case -EAGAIN: rds_stats_inc(s_recv_immediate_retry); queue_delayed_work(cp->cp_wq, &cp->cp_recv_w, 0); break; case -ENOMEM: rds_stats_inc(s_recv_delayed_retry); queue_delayed_work(cp->cp_wq, &cp->cp_recv_w, 2); break; default: break; } }}
void rds_shutdown_worker(struct work_struct *work){ struct rds_conn_path *cp = container_of(work, struct rds_conn_path, cp_down_w);
rds_conn_shutdown(cp);}
void rds_threads_exit(void){ destroy_workqueue(rds_wq);}
int rds_threads_init(void){ rds_wq = create_singlethread_workqueue("krdsd"); if (!rds_wq) return -ENOMEM;
return 0;}
/* Compare two IPv6 addresses. Return 0 if the two addresses are equal. * Return 1 if the first is greater. Return -1 if the second is greater. */int rds_addr_cmp(const struct in6_addr *addr1, const struct in6_addr *addr2){#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 const __be64 *a1, *a2; u64 x, y;
a1 = (__be64 *)addr1; a2 = (__be64 *)addr2;
if (*a1 != *a2) { if (be64_to_cpu(*a1) < be64_to_cpu(*a2)) return -1; else return 1; } else { x = be64_to_cpu(*++a1); y = be64_to_cpu(*++a2); if (x < y) return -1; else if (x > y) return 1; else return 0; }#else u32 a, b; int i;
for (i = 0; i < 4; i++) { if (addr1->s6_addr32[i] != addr2->s6_addr32[i]) { a = ntohl(addr1->s6_addr32[i]); b = ntohl(addr2->s6_addr32[i]); if (a < b) return -1; else if (a > b) return 1; } } return 0;#endif}EXPORT_SYMBOL_GPL(rds_addr_cmp);