diff options
Diffstat (limited to 'net/rds/connection.c')
| -rw-r--r-- | net/rds/connection.c | 591 |
1 files changed, 591 insertions, 0 deletions
diff --git a/net/rds/connection.c b/net/rds/connection.c new file mode 100644 index 000000000..da6da57e5 --- /dev/null +++ b/net/rds/connection.c @@ -0,0 +1,591 @@ +/* + * 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/list.h> +#include <linux/slab.h> +#include <linux/export.h> +#include <net/inet_hashtables.h> + +#include "rds.h" +#include "loop.h" + +#define RDS_CONNECTION_HASH_BITS 12 +#define RDS_CONNECTION_HASH_ENTRIES (1 << RDS_CONNECTION_HASH_BITS) +#define RDS_CONNECTION_HASH_MASK (RDS_CONNECTION_HASH_ENTRIES - 1) + +/* converting this to RCU is a chore for another day.. */ +static DEFINE_SPINLOCK(rds_conn_lock); +static unsigned long rds_conn_count; +static struct hlist_head rds_conn_hash[RDS_CONNECTION_HASH_ENTRIES]; +static struct kmem_cache *rds_conn_slab; + +static struct hlist_head *rds_conn_bucket(__be32 laddr, __be32 faddr) +{ + static u32 rds_hash_secret __read_mostly; + + unsigned long hash; + + net_get_random_once(&rds_hash_secret, sizeof(rds_hash_secret)); + + /* Pass NULL, don't need struct net for hash */ + hash = __inet_ehashfn(be32_to_cpu(laddr), 0, + be32_to_cpu(faddr), 0, + rds_hash_secret); + return &rds_conn_hash[hash & RDS_CONNECTION_HASH_MASK]; +} + +#define rds_conn_info_set(var, test, suffix) do { \ + if (test) \ + var |= RDS_INFO_CONNECTION_FLAG_##suffix; \ +} while (0) + +/* rcu read lock must be held or the connection spinlock */ +static struct rds_connection *rds_conn_lookup(struct hlist_head *head, + __be32 laddr, __be32 faddr, + struct rds_transport *trans) +{ + struct rds_connection *conn, *ret = NULL; + + hlist_for_each_entry_rcu(conn, head, c_hash_node) { + if (conn->c_faddr == faddr && conn->c_laddr == laddr && + conn->c_trans == trans) { + ret = conn; + break; + } + } + rdsdebug("returning conn %p for %pI4 -> %pI4\n", ret, + &laddr, &faddr); + return ret; +} + +/* + * This is called by transports as they're bringing down a connection. + * It clears partial message state so that the transport can start sending + * and receiving over this connection again in the future. It is up to + * the transport to have serialized this call with its send and recv. + */ +static void rds_conn_reset(struct rds_connection *conn) +{ + rdsdebug("connection %pI4 to %pI4 reset\n", + &conn->c_laddr, &conn->c_faddr); + + rds_stats_inc(s_conn_reset); + rds_send_reset(conn); + conn->c_flags = 0; + + /* Do not clear next_rx_seq here, else we cannot distinguish + * retransmitted packets from new packets, and will hand all + * of them to the application. That is not consistent with the + * reliability guarantees of RDS. */ +} + +/* + * There is only every one 'conn' for a given pair of addresses in the + * system at a time. They contain messages to be retransmitted and so + * span the lifetime of the actual underlying transport connections. + * + * For now they are not garbage collected once they're created. They + * are torn down as the module is removed, if ever. + */ +static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr, + struct rds_transport *trans, gfp_t gfp, + int is_outgoing) +{ + struct rds_connection *conn, *parent = NULL; + struct hlist_head *head = rds_conn_bucket(laddr, faddr); + struct rds_transport *loop_trans; + unsigned long flags; + int ret; + struct rds_transport *otrans = trans; + + if (!is_outgoing && otrans->t_type == RDS_TRANS_TCP) + goto new_conn; + rcu_read_lock(); + conn = rds_conn_lookup(head, laddr, faddr, trans); + if (conn && conn->c_loopback && conn->c_trans != &rds_loop_transport && + laddr == faddr && !is_outgoing) { + /* This is a looped back IB connection, and we're + * called by the code handling the incoming connect. + * We need a second connection object into which we + * can stick the other QP. */ + parent = conn; + conn = parent->c_passive; + } + rcu_read_unlock(); + if (conn) + goto out; + +new_conn: + conn = kmem_cache_zalloc(rds_conn_slab, gfp); + if (!conn) { + conn = ERR_PTR(-ENOMEM); + goto out; + } + + INIT_HLIST_NODE(&conn->c_hash_node); + conn->c_laddr = laddr; + conn->c_faddr = faddr; + spin_lock_init(&conn->c_lock); + conn->c_next_tx_seq = 1; + + init_waitqueue_head(&conn->c_waitq); + INIT_LIST_HEAD(&conn->c_send_queue); + INIT_LIST_HEAD(&conn->c_retrans); + + ret = rds_cong_get_maps(conn); + if (ret) { + kmem_cache_free(rds_conn_slab, conn); + conn = ERR_PTR(ret); + goto out; + } + + /* + * This is where a connection becomes loopback. If *any* RDS sockets + * can bind to the destination address then we'd rather the messages + * flow through loopback rather than either transport. + */ + loop_trans = rds_trans_get_preferred(faddr); + if (loop_trans) { + rds_trans_put(loop_trans); + conn->c_loopback = 1; + if (is_outgoing && trans->t_prefer_loopback) { + /* "outgoing" connection - and the transport + * says it wants the connection handled by the + * loopback transport. This is what TCP does. + */ + trans = &rds_loop_transport; + } + } + + conn->c_trans = trans; + + ret = trans->conn_alloc(conn, gfp); + if (ret) { + kmem_cache_free(rds_conn_slab, conn); + conn = ERR_PTR(ret); + goto out; + } + + atomic_set(&conn->c_state, RDS_CONN_DOWN); + conn->c_send_gen = 0; + conn->c_reconnect_jiffies = 0; + INIT_DELAYED_WORK(&conn->c_send_w, rds_send_worker); + INIT_DELAYED_WORK(&conn->c_recv_w, rds_recv_worker); + INIT_DELAYED_WORK(&conn->c_conn_w, rds_connect_worker); + INIT_WORK(&conn->c_down_w, rds_shutdown_worker); + mutex_init(&conn->c_cm_lock); + conn->c_flags = 0; + + rdsdebug("allocated conn %p for %pI4 -> %pI4 over %s %s\n", + conn, &laddr, &faddr, + trans->t_name ? trans->t_name : "[unknown]", + is_outgoing ? "(outgoing)" : ""); + + /* + * Since we ran without holding the conn lock, someone could + * have created the same conn (either normal or passive) in the + * interim. We check while holding the lock. If we won, we complete + * init and return our conn. If we lost, we rollback and return the + * other one. + */ + spin_lock_irqsave(&rds_conn_lock, flags); + if (parent) { + /* Creating passive conn */ + if (parent->c_passive) { + trans->conn_free(conn->c_transport_data); + kmem_cache_free(rds_conn_slab, conn); + conn = parent->c_passive; + } else { + parent->c_passive = conn; + rds_cong_add_conn(conn); + rds_conn_count++; + } + } else { + /* Creating normal conn */ + struct rds_connection *found; + + if (!is_outgoing && otrans->t_type == RDS_TRANS_TCP) + found = NULL; + else + found = rds_conn_lookup(head, laddr, faddr, trans); + if (found) { + trans->conn_free(conn->c_transport_data); + kmem_cache_free(rds_conn_slab, conn); + conn = found; + } else { + if ((is_outgoing && otrans->t_type == RDS_TRANS_TCP) || + (otrans->t_type != RDS_TRANS_TCP)) { + /* Only the active side should be added to + * reconnect list for TCP. + */ + hlist_add_head_rcu(&conn->c_hash_node, head); + } + rds_cong_add_conn(conn); + rds_conn_count++; + } + } + spin_unlock_irqrestore(&rds_conn_lock, flags); + +out: + return conn; +} + +struct rds_connection *rds_conn_create(__be32 laddr, __be32 faddr, + struct rds_transport *trans, gfp_t gfp) +{ + return __rds_conn_create(laddr, faddr, trans, gfp, 0); +} +EXPORT_SYMBOL_GPL(rds_conn_create); + +struct rds_connection *rds_conn_create_outgoing(__be32 laddr, __be32 faddr, + struct rds_transport *trans, gfp_t gfp) +{ + return __rds_conn_create(laddr, faddr, trans, gfp, 1); +} +EXPORT_SYMBOL_GPL(rds_conn_create_outgoing); + +void rds_conn_shutdown(struct rds_connection *conn) +{ + /* shut it down unless it's down already */ + if (!rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_DOWN)) { + /* + * Quiesce the connection mgmt handlers before we start tearing + * things down. We don't hold the mutex for the entire + * duration of the shutdown operation, else we may be + * deadlocking with the CM handler. Instead, the CM event + * handler is supposed to check for state DISCONNECTING + */ + mutex_lock(&conn->c_cm_lock); + if (!rds_conn_transition(conn, RDS_CONN_UP, RDS_CONN_DISCONNECTING) + && !rds_conn_transition(conn, RDS_CONN_ERROR, RDS_CONN_DISCONNECTING)) { + rds_conn_error(conn, "shutdown called in state %d\n", + atomic_read(&conn->c_state)); + mutex_unlock(&conn->c_cm_lock); + return; + } + mutex_unlock(&conn->c_cm_lock); + + wait_event(conn->c_waitq, + !test_bit(RDS_IN_XMIT, &conn->c_flags)); + + conn->c_trans->conn_shutdown(conn); + rds_conn_reset(conn); + + if (!rds_conn_transition(conn, RDS_CONN_DISCONNECTING, RDS_CONN_DOWN)) { + /* This can happen - eg when we're in the middle of tearing + * down the connection, and someone unloads the rds module. + * Quite reproduceable with loopback connections. + * Mostly harmless. + */ + rds_conn_error(conn, + "%s: failed to transition to state DOWN, " + "current state is %d\n", + __func__, + atomic_read(&conn->c_state)); + return; + } + } + + /* Then reconnect if it's still live. + * The passive side of an IB loopback connection is never added + * to the conn hash, so we never trigger a reconnect on this + * conn - the reconnect is always triggered by the active peer. */ + cancel_delayed_work_sync(&conn->c_conn_w); + rcu_read_lock(); + if (!hlist_unhashed(&conn->c_hash_node)) { + rcu_read_unlock(); + rds_queue_reconnect(conn); + } else { + rcu_read_unlock(); + } +} + +/* + * Stop and free a connection. + * + * This can only be used in very limited circumstances. It assumes that once + * the conn has been shutdown that no one else is referencing the connection. + * We can only ensure this in the rmmod path in the current code. + */ +void rds_conn_destroy(struct rds_connection *conn) +{ + struct rds_message *rm, *rtmp; + unsigned long flags; + + rdsdebug("freeing conn %p for %pI4 -> " + "%pI4\n", conn, &conn->c_laddr, + &conn->c_faddr); + + /* Ensure conn will not be scheduled for reconnect */ + spin_lock_irq(&rds_conn_lock); + hlist_del_init_rcu(&conn->c_hash_node); + spin_unlock_irq(&rds_conn_lock); + synchronize_rcu(); + + /* shut the connection down */ + rds_conn_drop(conn); + flush_work(&conn->c_down_w); + + /* make sure lingering queued work won't try to ref the conn */ + cancel_delayed_work_sync(&conn->c_send_w); + cancel_delayed_work_sync(&conn->c_recv_w); + + /* tear down queued messages */ + list_for_each_entry_safe(rm, rtmp, + &conn->c_send_queue, + m_conn_item) { + list_del_init(&rm->m_conn_item); + BUG_ON(!list_empty(&rm->m_sock_item)); + rds_message_put(rm); + } + if (conn->c_xmit_rm) + rds_message_put(conn->c_xmit_rm); + + conn->c_trans->conn_free(conn->c_transport_data); + + /* + * The congestion maps aren't freed up here. They're + * freed by rds_cong_exit() after all the connections + * have been freed. + */ + rds_cong_remove_conn(conn); + + BUG_ON(!list_empty(&conn->c_retrans)); + kmem_cache_free(rds_conn_slab, conn); + + spin_lock_irqsave(&rds_conn_lock, flags); + rds_conn_count--; + spin_unlock_irqrestore(&rds_conn_lock, flags); +} +EXPORT_SYMBOL_GPL(rds_conn_destroy); + +static void rds_conn_message_info(struct socket *sock, unsigned int len, + struct rds_info_iterator *iter, + struct rds_info_lengths *lens, + int want_send) +{ + struct hlist_head *head; + struct list_head *list; + struct rds_connection *conn; + struct rds_message *rm; + unsigned int total = 0; + unsigned long flags; + size_t i; + + len /= sizeof(struct rds_info_message); + + rcu_read_lock(); + + for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash); + i++, head++) { + hlist_for_each_entry_rcu(conn, head, c_hash_node) { + if (want_send) + list = &conn->c_send_queue; + else + list = &conn->c_retrans; + + spin_lock_irqsave(&conn->c_lock, flags); + + /* XXX too lazy to maintain counts.. */ + list_for_each_entry(rm, list, m_conn_item) { + total++; + if (total <= len) + rds_inc_info_copy(&rm->m_inc, iter, + conn->c_laddr, + conn->c_faddr, 0); + } + + spin_unlock_irqrestore(&conn->c_lock, flags); + } + } + rcu_read_unlock(); + + lens->nr = total; + lens->each = sizeof(struct rds_info_message); +} + +static void rds_conn_message_info_send(struct socket *sock, unsigned int len, + struct rds_info_iterator *iter, + struct rds_info_lengths *lens) +{ + rds_conn_message_info(sock, len, iter, lens, 1); +} + +static void rds_conn_message_info_retrans(struct socket *sock, + unsigned int len, + struct rds_info_iterator *iter, + struct rds_info_lengths *lens) +{ + rds_conn_message_info(sock, len, iter, lens, 0); +} + +void rds_for_each_conn_info(struct socket *sock, unsigned int len, + struct rds_info_iterator *iter, + struct rds_info_lengths *lens, + int (*visitor)(struct rds_connection *, void *), + size_t item_len) +{ + uint64_t buffer[(item_len + 7) / 8]; + struct hlist_head *head; + struct rds_connection *conn; + size_t i; + + rcu_read_lock(); + + lens->nr = 0; + lens->each = item_len; + + for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash); + i++, head++) { + hlist_for_each_entry_rcu(conn, head, c_hash_node) { + + /* XXX no c_lock usage.. */ + if (!visitor(conn, buffer)) + continue; + + /* We copy as much as we can fit in the buffer, + * but we count all items so that the caller + * can resize the buffer. */ + if (len >= item_len) { + rds_info_copy(iter, buffer, item_len); + len -= item_len; + } + lens->nr++; + } + } + rcu_read_unlock(); +} +EXPORT_SYMBOL_GPL(rds_for_each_conn_info); + +static int rds_conn_info_visitor(struct rds_connection *conn, + void *buffer) +{ + struct rds_info_connection *cinfo = buffer; + + cinfo->next_tx_seq = conn->c_next_tx_seq; + cinfo->next_rx_seq = conn->c_next_rx_seq; + cinfo->laddr = conn->c_laddr; + cinfo->faddr = conn->c_faddr; + strncpy(cinfo->transport, conn->c_trans->t_name, + sizeof(cinfo->transport)); + cinfo->flags = 0; + + rds_conn_info_set(cinfo->flags, test_bit(RDS_IN_XMIT, &conn->c_flags), + SENDING); + /* XXX Future: return the state rather than these funky bits */ + rds_conn_info_set(cinfo->flags, + atomic_read(&conn->c_state) == RDS_CONN_CONNECTING, + CONNECTING); + rds_conn_info_set(cinfo->flags, + atomic_read(&conn->c_state) == RDS_CONN_UP, + CONNECTED); + return 1; +} + +static void rds_conn_info(struct socket *sock, unsigned int len, + struct rds_info_iterator *iter, + struct rds_info_lengths *lens) +{ + rds_for_each_conn_info(sock, len, iter, lens, + rds_conn_info_visitor, + sizeof(struct rds_info_connection)); +} + +int rds_conn_init(void) +{ + rds_conn_slab = kmem_cache_create("rds_connection", + sizeof(struct rds_connection), + 0, 0, NULL); + if (!rds_conn_slab) + return -ENOMEM; + + rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info); + rds_info_register_func(RDS_INFO_SEND_MESSAGES, + rds_conn_message_info_send); + rds_info_register_func(RDS_INFO_RETRANS_MESSAGES, + rds_conn_message_info_retrans); + + return 0; +} + +void rds_conn_exit(void) +{ + rds_loop_exit(); + + WARN_ON(!hlist_empty(rds_conn_hash)); + + kmem_cache_destroy(rds_conn_slab); + + rds_info_deregister_func(RDS_INFO_CONNECTIONS, rds_conn_info); + rds_info_deregister_func(RDS_INFO_SEND_MESSAGES, + rds_conn_message_info_send); + rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES, + rds_conn_message_info_retrans); +} + +/* + * Force a disconnect + */ +void rds_conn_drop(struct rds_connection *conn) +{ + atomic_set(&conn->c_state, RDS_CONN_ERROR); + queue_work(rds_wq, &conn->c_down_w); +} +EXPORT_SYMBOL_GPL(rds_conn_drop); + +/* + * If the connection is down, trigger a connect. We may have scheduled a + * delayed reconnect however - in this case we should not interfere. + */ +void rds_conn_connect_if_down(struct rds_connection *conn) +{ + if (rds_conn_state(conn) == RDS_CONN_DOWN && + !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags)) + queue_delayed_work(rds_wq, &conn->c_conn_w, 0); +} +EXPORT_SYMBOL_GPL(rds_conn_connect_if_down); + +/* + * An error occurred on the connection + */ +void +__rds_conn_error(struct rds_connection *conn, const char *fmt, ...) +{ + va_list ap; + + va_start(ap, fmt); + vprintk(fmt, ap); + va_end(ap); + + rds_conn_drop(conn); +} |