/*
* 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 <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)
{
/* Pass NULL, don't need struct net for hash */
unsigned long hash = inet_ehashfn(NULL,
be32_to_cpu(laddr), 0,
be32_to_cpu(faddr), 0);
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;
struct hlist_node *pos;
hlist_for_each_entry_rcu(conn, pos, 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.
*/
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;
rcu_read_lock();
conn = rds_conn_lookup(head, laddr, faddr, trans);
if (conn && conn->c_loopback && conn->c_trans != &rds_loop_transport &&
!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;
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_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;
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 {
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);
/* 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 hlist_node *pos;
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, pos, 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 hlist_node *pos;
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, pos, 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);
}
