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OpenCloudOS-Kernel/net/rxrpc/conn_client.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/* Client connection-specific management code.
*
* Copyright (C) 2016, 2020 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* Client connections need to be cached for a little while after they've made a
* call so as to handle retransmitted DATA packets in case the server didn't
* receive the final ACK or terminating ABORT we sent it.
*
* There are flags of relevance to the cache:
*
* (2) DONT_REUSE - The connection should be discarded as soon as possible and
* should not be reused. This is set when an exclusive connection is used
* or a call ID counter overflows.
*
* The caching state may only be changed if the cache lock is held.
*
* There are two idle client connection expiry durations. If the total number
* of connections is below the reap threshold, we use the normal duration; if
* it's above, we use the fast duration.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/slab.h>
#include <linux/idr.h>
#include <linux/timer.h>
#include <linux/sched/signal.h>
#include "ar-internal.h"
__read_mostly unsigned int rxrpc_reap_client_connections = 900;
__read_mostly unsigned long rxrpc_conn_idle_client_expiry = 2 * 60 * HZ;
__read_mostly unsigned long rxrpc_conn_idle_client_fast_expiry = 2 * HZ;
/*
* We use machine-unique IDs for our client connections.
*/
DEFINE_IDR(rxrpc_client_conn_ids);
static DEFINE_SPINLOCK(rxrpc_conn_id_lock);
/*
* Get a connection ID and epoch for a client connection from the global pool.
* The connection struct pointer is then recorded in the idr radix tree. The
* epoch doesn't change until the client is rebooted (or, at least, unless the
* module is unloaded).
*/
static int rxrpc_get_client_connection_id(struct rxrpc_connection *conn,
gfp_t gfp)
{
struct rxrpc_net *rxnet = conn->params.local->rxnet;
int id;
_enter("");
idr_preload(gfp);
spin_lock(&rxrpc_conn_id_lock);
id = idr_alloc_cyclic(&rxrpc_client_conn_ids, conn,
1, 0x40000000, GFP_NOWAIT);
if (id < 0)
goto error;
spin_unlock(&rxrpc_conn_id_lock);
idr_preload_end();
conn->proto.epoch = rxnet->epoch;
conn->proto.cid = id << RXRPC_CIDSHIFT;
set_bit(RXRPC_CONN_HAS_IDR, &conn->flags);
_leave(" [CID %x]", conn->proto.cid);
return 0;
error:
spin_unlock(&rxrpc_conn_id_lock);
idr_preload_end();
_leave(" = %d", id);
return id;
}
/*
* Release a connection ID for a client connection from the global pool.
*/
static void rxrpc_put_client_connection_id(struct rxrpc_connection *conn)
{
if (test_bit(RXRPC_CONN_HAS_IDR, &conn->flags)) {
spin_lock(&rxrpc_conn_id_lock);
idr_remove(&rxrpc_client_conn_ids,
conn->proto.cid >> RXRPC_CIDSHIFT);
spin_unlock(&rxrpc_conn_id_lock);
}
}
/*
* Destroy the client connection ID tree.
*/
void rxrpc_destroy_client_conn_ids(void)
{
struct rxrpc_connection *conn;
int id;
if (!idr_is_empty(&rxrpc_client_conn_ids)) {
idr_for_each_entry(&rxrpc_client_conn_ids, conn, id) {
pr_err("AF_RXRPC: Leaked client conn %p {%d}\n",
conn, refcount_read(&conn->ref));
}
BUG();
}
idr_destroy(&rxrpc_client_conn_ids);
}
/*
* Allocate a connection bundle.
*/
static struct rxrpc_bundle *rxrpc_alloc_bundle(struct rxrpc_conn_parameters *cp,
gfp_t gfp)
{
struct rxrpc_bundle *bundle;
bundle = kzalloc(sizeof(*bundle), gfp);
if (bundle) {
bundle->params = *cp;
rxrpc_get_peer(bundle->params.peer);
refcount_set(&bundle->ref, 1);
spin_lock_init(&bundle->channel_lock);
INIT_LIST_HEAD(&bundle->waiting_calls);
}
return bundle;
}
struct rxrpc_bundle *rxrpc_get_bundle(struct rxrpc_bundle *bundle)
{
refcount_inc(&bundle->ref);
return bundle;
}
static void rxrpc_free_bundle(struct rxrpc_bundle *bundle)
{
rxrpc_put_peer(bundle->params.peer);
kfree(bundle);
}
void rxrpc_put_bundle(struct rxrpc_bundle *bundle)
{
unsigned int d = bundle->debug_id;
bool dead;
int r;
dead = __refcount_dec_and_test(&bundle->ref, &r);
_debug("PUT B=%x %d", d, r);
if (dead)
rxrpc_free_bundle(bundle);
}
/*
* Allocate a client connection.
*/
static struct rxrpc_connection *
rxrpc_alloc_client_connection(struct rxrpc_bundle *bundle, gfp_t gfp)
{
struct rxrpc_connection *conn;
struct rxrpc_net *rxnet = bundle->params.local->rxnet;
int ret;
_enter("");
conn = rxrpc_alloc_connection(gfp);
if (!conn) {
_leave(" = -ENOMEM");
return ERR_PTR(-ENOMEM);
}
refcount_set(&conn->ref, 1);
conn->bundle = bundle;
conn->params = bundle->params;
conn->out_clientflag = RXRPC_CLIENT_INITIATED;
conn->state = RXRPC_CONN_CLIENT;
conn->service_id = conn->params.service_id;
ret = rxrpc_get_client_connection_id(conn, gfp);
if (ret < 0)
goto error_0;
ret = rxrpc_init_client_conn_security(conn);
if (ret < 0)
goto error_1;
atomic_inc(&rxnet->nr_conns);
write_lock(&rxnet->conn_lock);
list_add_tail(&conn->proc_link, &rxnet->conn_proc_list);
write_unlock(&rxnet->conn_lock);
rxrpc_get_bundle(bundle);
rxrpc_get_peer(conn->params.peer);
rxrpc_get_local(conn->params.local);
key_get(conn->params.key);
trace_rxrpc_conn(conn->debug_id, rxrpc_conn_new_client,
refcount_read(&conn->ref),
__builtin_return_address(0));
atomic_inc(&rxnet->nr_client_conns);
trace_rxrpc_client(conn, -1, rxrpc_client_alloc);
_leave(" = %p", conn);
return conn;
error_1:
rxrpc_put_client_connection_id(conn);
error_0:
kfree(conn);
_leave(" = %d", ret);
return ERR_PTR(ret);
}
/*
* Determine if a connection may be reused.
*/
static bool rxrpc_may_reuse_conn(struct rxrpc_connection *conn)
{
struct rxrpc_net *rxnet;
int id_cursor, id, distance, limit;
if (!conn)
goto dont_reuse;
rxnet = conn->params.local->rxnet;
if (test_bit(RXRPC_CONN_DONT_REUSE, &conn->flags))
goto dont_reuse;
if (conn->state != RXRPC_CONN_CLIENT ||
conn->proto.epoch != rxnet->epoch)
goto mark_dont_reuse;
/* The IDR tree gets very expensive on memory if the connection IDs are
* widely scattered throughout the number space, so we shall want to
* kill off connections that, say, have an ID more than about four
* times the maximum number of client conns away from the current
* allocation point to try and keep the IDs concentrated.
*/
id_cursor = idr_get_cursor(&rxrpc_client_conn_ids);
id = conn->proto.cid >> RXRPC_CIDSHIFT;
distance = id - id_cursor;
if (distance < 0)
distance = -distance;
limit = max_t(unsigned long, atomic_read(&rxnet->nr_conns) * 4, 1024);
if (distance > limit)
goto mark_dont_reuse;
return true;
mark_dont_reuse:
set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
dont_reuse:
return false;
}
/*
* Look up the conn bundle that matches the connection parameters, adding it if
* it doesn't yet exist.
*/
static struct rxrpc_bundle *rxrpc_look_up_bundle(struct rxrpc_conn_parameters *cp,
gfp_t gfp)
{
static atomic_t rxrpc_bundle_id;
struct rxrpc_bundle *bundle, *candidate;
struct rxrpc_local *local = cp->local;
struct rb_node *p, **pp, *parent;
long diff;
_enter("{%px,%x,%u,%u}",
cp->peer, key_serial(cp->key), cp->security_level, cp->upgrade);
if (cp->exclusive)
return rxrpc_alloc_bundle(cp, gfp);
/* First, see if the bundle is already there. */
_debug("search 1");
spin_lock(&local->client_bundles_lock);
p = local->client_bundles.rb_node;
while (p) {
bundle = rb_entry(p, struct rxrpc_bundle, local_node);
#define cmp(X) ((long)bundle->params.X - (long)cp->X)
diff = (cmp(peer) ?:
cmp(key) ?:
cmp(security_level) ?:
cmp(upgrade));
#undef cmp
if (diff < 0)
p = p->rb_left;
else if (diff > 0)
p = p->rb_right;
else
goto found_bundle;
}
spin_unlock(&local->client_bundles_lock);
_debug("not found");
/* It wasn't. We need to add one. */
candidate = rxrpc_alloc_bundle(cp, gfp);
if (!candidate)
return NULL;
_debug("search 2");
spin_lock(&local->client_bundles_lock);
pp = &local->client_bundles.rb_node;
parent = NULL;
while (*pp) {
parent = *pp;
bundle = rb_entry(parent, struct rxrpc_bundle, local_node);
#define cmp(X) ((long)bundle->params.X - (long)cp->X)
diff = (cmp(peer) ?:
cmp(key) ?:
cmp(security_level) ?:
cmp(upgrade));
#undef cmp
if (diff < 0)
pp = &(*pp)->rb_left;
else if (diff > 0)
pp = &(*pp)->rb_right;
else
goto found_bundle_free;
}
_debug("new bundle");
candidate->debug_id = atomic_inc_return(&rxrpc_bundle_id);
rb_link_node(&candidate->local_node, parent, pp);
rb_insert_color(&candidate->local_node, &local->client_bundles);
rxrpc_get_bundle(candidate);
spin_unlock(&local->client_bundles_lock);
_leave(" = %u [new]", candidate->debug_id);
return candidate;
found_bundle_free:
rxrpc_free_bundle(candidate);
found_bundle:
rxrpc_get_bundle(bundle);
spin_unlock(&local->client_bundles_lock);
_leave(" = %u [found]", bundle->debug_id);
return bundle;
}
/*
* Create or find a client bundle to use for a call.
*
* If we return with a connection, the call will be on its waiting list. It's
* left to the caller to assign a channel and wake up the call.
*/
static struct rxrpc_bundle *rxrpc_prep_call(struct rxrpc_sock *rx,
struct rxrpc_call *call,
struct rxrpc_conn_parameters *cp,
struct sockaddr_rxrpc *srx,
gfp_t gfp)
{
struct rxrpc_bundle *bundle;
_enter("{%d,%lx},", call->debug_id, call->user_call_ID);
cp->peer = rxrpc_lookup_peer(rx, cp->local, srx, gfp);
if (!cp->peer)
goto error;
call->cong_cwnd = cp->peer->cong_cwnd;
if (call->cong_cwnd >= call->cong_ssthresh)
call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
else
call->cong_mode = RXRPC_CALL_SLOW_START;
if (cp->upgrade)
__set_bit(RXRPC_CALL_UPGRADE, &call->flags);
/* Find the client connection bundle. */
bundle = rxrpc_look_up_bundle(cp, gfp);
if (!bundle)
goto error;
/* Get this call queued. Someone else may activate it whilst we're
* lining up a new connection, but that's fine.
*/
spin_lock(&bundle->channel_lock);
list_add_tail(&call->chan_wait_link, &bundle->waiting_calls);
spin_unlock(&bundle->channel_lock);
_leave(" = [B=%x]", bundle->debug_id);
return bundle;
error:
_leave(" = -ENOMEM");
return ERR_PTR(-ENOMEM);
}
/*
* Allocate a new connection and add it into a bundle.
*/
static void rxrpc_add_conn_to_bundle(struct rxrpc_bundle *bundle, gfp_t gfp)
__releases(bundle->channel_lock)
{
struct rxrpc_connection *candidate = NULL, *old = NULL;
bool conflict;
int i;
_enter("");
conflict = bundle->alloc_conn;
if (!conflict)
bundle->alloc_conn = true;
spin_unlock(&bundle->channel_lock);
if (conflict) {
_leave(" [conf]");
return;
}
candidate = rxrpc_alloc_client_connection(bundle, gfp);
spin_lock(&bundle->channel_lock);
bundle->alloc_conn = false;
if (IS_ERR(candidate)) {
bundle->alloc_error = PTR_ERR(candidate);
spin_unlock(&bundle->channel_lock);
_leave(" [err %ld]", PTR_ERR(candidate));
return;
}
bundle->alloc_error = 0;
for (i = 0; i < ARRAY_SIZE(bundle->conns); i++) {
unsigned int shift = i * RXRPC_MAXCALLS;
int j;
old = bundle->conns[i];
if (!rxrpc_may_reuse_conn(old)) {
if (old)
trace_rxrpc_client(old, -1, rxrpc_client_replace);
candidate->bundle_shift = shift;
bundle->conns[i] = candidate;
for (j = 0; j < RXRPC_MAXCALLS; j++)
set_bit(shift + j, &bundle->avail_chans);
candidate = NULL;
break;
}
old = NULL;
}
spin_unlock(&bundle->channel_lock);
if (candidate) {
_debug("discard C=%x", candidate->debug_id);
trace_rxrpc_client(candidate, -1, rxrpc_client_duplicate);
rxrpc_put_connection(candidate);
}
rxrpc_put_connection(old);
_leave("");
}
/*
* Add a connection to a bundle if there are no usable connections or we have
* connections waiting for extra capacity.
*/
static void rxrpc_maybe_add_conn(struct rxrpc_bundle *bundle, gfp_t gfp)
{
struct rxrpc_call *call;
int i, usable;
_enter("");
spin_lock(&bundle->channel_lock);
/* See if there are any usable connections. */
usable = 0;
for (i = 0; i < ARRAY_SIZE(bundle->conns); i++)
if (rxrpc_may_reuse_conn(bundle->conns[i]))
usable++;
if (!usable && !list_empty(&bundle->waiting_calls)) {
call = list_first_entry(&bundle->waiting_calls,
struct rxrpc_call, chan_wait_link);
if (test_bit(RXRPC_CALL_UPGRADE, &call->flags))
bundle->try_upgrade = true;
}
if (!usable)
goto alloc_conn;
if (!bundle->avail_chans &&
!bundle->try_upgrade &&
!list_empty(&bundle->waiting_calls) &&
usable < ARRAY_SIZE(bundle->conns))
goto alloc_conn;
spin_unlock(&bundle->channel_lock);
_leave("");
return;
alloc_conn:
return rxrpc_add_conn_to_bundle(bundle, gfp);
}
/*
* Assign a channel to the call at the front of the queue and wake the call up.
* We don't increment the callNumber counter until this number has been exposed
* to the world.
*/
static void rxrpc_activate_one_channel(struct rxrpc_connection *conn,
unsigned int channel)
{
struct rxrpc_channel *chan = &conn->channels[channel];
struct rxrpc_bundle *bundle = conn->bundle;
struct rxrpc_call *call = list_entry(bundle->waiting_calls.next,
struct rxrpc_call, chan_wait_link);
u32 call_id = chan->call_counter + 1;
_enter("C=%x,%u", conn->debug_id, channel);
trace_rxrpc_client(conn, channel, rxrpc_client_chan_activate);
/* Cancel the final ACK on the previous call if it hasn't been sent yet
* as the DATA packet will implicitly ACK it.
*/
clear_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags);
clear_bit(conn->bundle_shift + channel, &bundle->avail_chans);
rxrpc_see_call(call);
list_del_init(&call->chan_wait_link);
call->peer = rxrpc_get_peer(conn->params.peer);
call->conn = rxrpc_get_connection(conn);
call->cid = conn->proto.cid | channel;
call->call_id = call_id;
call->security = conn->security;
call->security_ix = conn->security_ix;
call->service_id = conn->service_id;
trace_rxrpc_connect_call(call);
_net("CONNECT call %08x:%08x as call %d on conn %d",
call->cid, call->call_id, call->debug_id, conn->debug_id);
write_lock_bh(&call->state_lock);
call->state = RXRPC_CALL_CLIENT_SEND_REQUEST;
write_unlock_bh(&call->state_lock);
/* Paired with the read barrier in rxrpc_connect_call(). This orders
* cid and epoch in the connection wrt to call_id without the need to
* take the channel_lock.
*
* We provisionally assign a callNumber at this point, but we don't
* confirm it until the call is about to be exposed.
*
* TODO: Pair with a barrier in the data_ready handler when that looks
* at the call ID through a connection channel.
*/
smp_wmb();
chan->call_id = call_id;
chan->call_debug_id = call->debug_id;
rcu_assign_pointer(chan->call, call);
wake_up(&call->waitq);
}
/*
* Remove a connection from the idle list if it's on it.
*/
static void rxrpc_unidle_conn(struct rxrpc_bundle *bundle, struct rxrpc_connection *conn)
{
struct rxrpc_net *rxnet = bundle->params.local->rxnet;
bool drop_ref;
if (!list_empty(&conn->cache_link)) {
drop_ref = false;
spin_lock(&rxnet->client_conn_cache_lock);
if (!list_empty(&conn->cache_link)) {
list_del_init(&conn->cache_link);
drop_ref = true;
}
spin_unlock(&rxnet->client_conn_cache_lock);
if (drop_ref)
rxrpc_put_connection(conn);
}
}
/*
* Assign channels and callNumbers to waiting calls with channel_lock
* held by caller.
*/
static void rxrpc_activate_channels_locked(struct rxrpc_bundle *bundle)
{
struct rxrpc_connection *conn;
unsigned long avail, mask;
unsigned int channel, slot;
if (bundle->try_upgrade)
mask = 1;
else
mask = ULONG_MAX;
while (!list_empty(&bundle->waiting_calls)) {
avail = bundle->avail_chans & mask;
if (!avail)
break;
channel = __ffs(avail);
clear_bit(channel, &bundle->avail_chans);
slot = channel / RXRPC_MAXCALLS;
conn = bundle->conns[slot];
if (!conn)
break;
if (bundle->try_upgrade)
set_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags);
rxrpc_unidle_conn(bundle, conn);
channel &= (RXRPC_MAXCALLS - 1);
conn->act_chans |= 1 << channel;
rxrpc_activate_one_channel(conn, channel);
}
}
/*
* Assign channels and callNumbers to waiting calls.
*/
static void rxrpc_activate_channels(struct rxrpc_bundle *bundle)
{
_enter("B=%x", bundle->debug_id);
trace_rxrpc_client(NULL, -1, rxrpc_client_activate_chans);
if (!bundle->avail_chans)
return;
spin_lock(&bundle->channel_lock);
rxrpc_activate_channels_locked(bundle);
spin_unlock(&bundle->channel_lock);
_leave("");
}
/*
* Wait for a callNumber and a channel to be granted to a call.
*/
static int rxrpc_wait_for_channel(struct rxrpc_bundle *bundle,
struct rxrpc_call *call, gfp_t gfp)
{
DECLARE_WAITQUEUE(myself, current);
int ret = 0;
_enter("%d", call->debug_id);
if (!gfpflags_allow_blocking(gfp)) {
rxrpc_maybe_add_conn(bundle, gfp);
rxrpc_activate_channels(bundle);
ret = bundle->alloc_error ?: -EAGAIN;
goto out;
}
add_wait_queue_exclusive(&call->waitq, &myself);
for (;;) {
rxrpc_maybe_add_conn(bundle, gfp);
rxrpc_activate_channels(bundle);
ret = bundle->alloc_error;
if (ret < 0)
break;
switch (call->interruptibility) {
case RXRPC_INTERRUPTIBLE:
case RXRPC_PREINTERRUPTIBLE:
set_current_state(TASK_INTERRUPTIBLE);
break;
case RXRPC_UNINTERRUPTIBLE:
default:
set_current_state(TASK_UNINTERRUPTIBLE);
break;
}
if (READ_ONCE(call->state) != RXRPC_CALL_CLIENT_AWAIT_CONN)
break;
if ((call->interruptibility == RXRPC_INTERRUPTIBLE ||
call->interruptibility == RXRPC_PREINTERRUPTIBLE) &&
signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
schedule();
}
remove_wait_queue(&call->waitq, &myself);
__set_current_state(TASK_RUNNING);
out:
_leave(" = %d", ret);
return ret;
}
/*
* find a connection for a call
* - called in process context with IRQs enabled
*/
int rxrpc_connect_call(struct rxrpc_sock *rx,
struct rxrpc_call *call,
struct rxrpc_conn_parameters *cp,
struct sockaddr_rxrpc *srx,
gfp_t gfp)
{
struct rxrpc_bundle *bundle;
struct rxrpc_net *rxnet = cp->local->rxnet;
int ret = 0;
_enter("{%d,%lx},", call->debug_id, call->user_call_ID);
rxrpc_discard_expired_client_conns(&rxnet->client_conn_reaper);
bundle = rxrpc_prep_call(rx, call, cp, srx, gfp);
if (IS_ERR(bundle)) {
ret = PTR_ERR(bundle);
goto out;
}
if (call->state == RXRPC_CALL_CLIENT_AWAIT_CONN) {
ret = rxrpc_wait_for_channel(bundle, call, gfp);
if (ret < 0)
goto wait_failed;
}
granted_channel:
/* Paired with the write barrier in rxrpc_activate_one_channel(). */
smp_rmb();
out_put_bundle:
rxrpc_put_bundle(bundle);
out:
_leave(" = %d", ret);
return ret;
wait_failed:
spin_lock(&bundle->channel_lock);
list_del_init(&call->chan_wait_link);
spin_unlock(&bundle->channel_lock);
if (call->state != RXRPC_CALL_CLIENT_AWAIT_CONN) {
ret = 0;
goto granted_channel;
}
trace_rxrpc_client(call->conn, ret, rxrpc_client_chan_wait_failed);
rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR, 0, ret);
rxrpc_disconnect_client_call(bundle, call);
goto out_put_bundle;
}
/*
* Note that a call, and thus a connection, is about to be exposed to the
* world.
*/
void rxrpc_expose_client_call(struct rxrpc_call *call)
{
unsigned int channel = call->cid & RXRPC_CHANNELMASK;
struct rxrpc_connection *conn = call->conn;
struct rxrpc_channel *chan = &conn->channels[channel];
if (!test_and_set_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
/* Mark the call ID as being used. If the callNumber counter
* exceeds ~2 billion, we kill the connection after its
* outstanding calls have finished so that the counter doesn't
* wrap.
*/
chan->call_counter++;
if (chan->call_counter >= INT_MAX)
set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
trace_rxrpc_client(conn, channel, rxrpc_client_exposed);
}
}
/*
* Set the reap timer.
*/
static void rxrpc_set_client_reap_timer(struct rxrpc_net *rxnet)
{
if (!rxnet->kill_all_client_conns) {
unsigned long now = jiffies;
unsigned long reap_at = now + rxrpc_conn_idle_client_expiry;
if (rxnet->live)
timer_reduce(&rxnet->client_conn_reap_timer, reap_at);
}
}
/*
* Disconnect a client call.
*/
void rxrpc_disconnect_client_call(struct rxrpc_bundle *bundle, struct rxrpc_call *call)
{
struct rxrpc_connection *conn;
struct rxrpc_channel *chan = NULL;
struct rxrpc_net *rxnet = bundle->params.local->rxnet;
unsigned int channel;
bool may_reuse;
u32 cid;
_enter("c=%x", call->debug_id);
spin_lock(&bundle->channel_lock);
set_bit(RXRPC_CALL_DISCONNECTED, &call->flags);
/* Calls that have never actually been assigned a channel can simply be
* discarded.
*/
conn = call->conn;
if (!conn) {
_debug("call is waiting");
ASSERTCMP(call->call_id, ==, 0);
ASSERT(!test_bit(RXRPC_CALL_EXPOSED, &call->flags));
list_del_init(&call->chan_wait_link);
goto out;
}
cid = call->cid;
channel = cid & RXRPC_CHANNELMASK;
chan = &conn->channels[channel];
trace_rxrpc_client(conn, channel, rxrpc_client_chan_disconnect);
if (rcu_access_pointer(chan->call) != call) {
spin_unlock(&bundle->channel_lock);
BUG();
}
may_reuse = rxrpc_may_reuse_conn(conn);
/* If a client call was exposed to the world, we save the result for
* retransmission.
*
* We use a barrier here so that the call number and abort code can be
* read without needing to take a lock.
*
* TODO: Make the incoming packet handler check this and handle
* terminal retransmission without requiring access to the call.
*/
if (test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
_debug("exposed %u,%u", call->call_id, call->abort_code);
__rxrpc_disconnect_call(conn, call);
if (test_and_clear_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags)) {
trace_rxrpc_client(conn, channel, rxrpc_client_to_active);
bundle->try_upgrade = false;
if (may_reuse)
rxrpc_activate_channels_locked(bundle);
}
}
/* See if we can pass the channel directly to another call. */
if (may_reuse && !list_empty(&bundle->waiting_calls)) {
trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass);
rxrpc_activate_one_channel(conn, channel);
goto out;
}
/* Schedule the final ACK to be transmitted in a short while so that it
* can be skipped if we find a follow-on call. The first DATA packet
* of the follow on call will implicitly ACK this call.
*/
if (call->completion == RXRPC_CALL_SUCCEEDED &&
test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
unsigned long final_ack_at = jiffies + 2;
WRITE_ONCE(chan->final_ack_at, final_ack_at);
smp_wmb(); /* vs rxrpc_process_delayed_final_acks() */
set_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags);
rxrpc_reduce_conn_timer(conn, final_ack_at);
}
/* Deactivate the channel. */
rcu_assign_pointer(chan->call, NULL);
set_bit(conn->bundle_shift + channel, &conn->bundle->avail_chans);
conn->act_chans &= ~(1 << channel);
/* If no channels remain active, then put the connection on the idle
* list for a short while. Give it a ref to stop it going away if it
* becomes unbundled.
*/
if (!conn->act_chans) {
trace_rxrpc_client(conn, channel, rxrpc_client_to_idle);
conn->idle_timestamp = jiffies;
rxrpc_get_connection(conn);
spin_lock(&rxnet->client_conn_cache_lock);
list_move_tail(&conn->cache_link, &rxnet->idle_client_conns);
spin_unlock(&rxnet->client_conn_cache_lock);
rxrpc_set_client_reap_timer(rxnet);
}
out:
spin_unlock(&bundle->channel_lock);
_leave("");
return;
}
/*
* Remove a connection from a bundle.
*/
static void rxrpc_unbundle_conn(struct rxrpc_connection *conn)
{
struct rxrpc_bundle *bundle = conn->bundle;
struct rxrpc_local *local = bundle->params.local;
unsigned int bindex;
bool need_drop = false, need_put = false;
int i;
_enter("C=%x", conn->debug_id);
if (conn->flags & RXRPC_CONN_FINAL_ACK_MASK)
rxrpc_process_delayed_final_acks(conn, true);
spin_lock(&bundle->channel_lock);
bindex = conn->bundle_shift / RXRPC_MAXCALLS;
if (bundle->conns[bindex] == conn) {
_debug("clear slot %u", bindex);
bundle->conns[bindex] = NULL;
for (i = 0; i < RXRPC_MAXCALLS; i++)
clear_bit(conn->bundle_shift + i, &bundle->avail_chans);
need_drop = true;
}
spin_unlock(&bundle->channel_lock);
/* If there are no more connections, remove the bundle */
if (!bundle->avail_chans) {
_debug("maybe unbundle");
spin_lock(&local->client_bundles_lock);
for (i = 0; i < ARRAY_SIZE(bundle->conns); i++)
if (bundle->conns[i])
break;
if (i == ARRAY_SIZE(bundle->conns) && !bundle->params.exclusive) {
_debug("erase bundle");
rb_erase(&bundle->local_node, &local->client_bundles);
need_put = true;
}
spin_unlock(&local->client_bundles_lock);
if (need_put)
rxrpc_put_bundle(bundle);
}
if (need_drop)
rxrpc_put_connection(conn);
_leave("");
}
/*
* Clean up a dead client connection.
*/
static void rxrpc_kill_client_conn(struct rxrpc_connection *conn)
{
struct rxrpc_local *local = conn->params.local;
struct rxrpc_net *rxnet = local->rxnet;
_enter("C=%x", conn->debug_id);
trace_rxrpc_client(conn, -1, rxrpc_client_cleanup);
atomic_dec(&rxnet->nr_client_conns);
rxrpc_put_client_connection_id(conn);
rxrpc_kill_connection(conn);
}
/*
* Clean up a dead client connections.
*/
void rxrpc_put_client_conn(struct rxrpc_connection *conn)
{
const void *here = __builtin_return_address(0);
unsigned int debug_id = conn->debug_id;
bool dead;
int r;
dead = __refcount_dec_and_test(&conn->ref, &r);
trace_rxrpc_conn(debug_id, rxrpc_conn_put_client, r - 1, here);
if (dead)
rxrpc_kill_client_conn(conn);
}
/*
* Discard expired client connections from the idle list. Each conn in the
* idle list has been exposed and holds an extra ref because of that.
*
* This may be called from conn setup or from a work item so cannot be
* considered non-reentrant.
*/
void rxrpc_discard_expired_client_conns(struct work_struct *work)
{
struct rxrpc_connection *conn;
struct rxrpc_net *rxnet =
container_of(work, struct rxrpc_net, client_conn_reaper);
unsigned long expiry, conn_expires_at, now;
unsigned int nr_conns;
_enter("");
if (list_empty(&rxnet->idle_client_conns)) {
_leave(" [empty]");
return;
}
/* Don't double up on the discarding */
if (!spin_trylock(&rxnet->client_conn_discard_lock)) {
_leave(" [already]");
return;
}
/* We keep an estimate of what the number of conns ought to be after
* we've discarded some so that we don't overdo the discarding.
*/
nr_conns = atomic_read(&rxnet->nr_client_conns);
next:
spin_lock(&rxnet->client_conn_cache_lock);
if (list_empty(&rxnet->idle_client_conns))
goto out;
conn = list_entry(rxnet->idle_client_conns.next,
struct rxrpc_connection, cache_link);
if (!rxnet->kill_all_client_conns) {
/* If the number of connections is over the reap limit, we
* expedite discard by reducing the expiry timeout. We must,
* however, have at least a short grace period to be able to do
* final-ACK or ABORT retransmission.
*/
expiry = rxrpc_conn_idle_client_expiry;
if (nr_conns > rxrpc_reap_client_connections)
expiry = rxrpc_conn_idle_client_fast_expiry;
if (conn->params.local->service_closed)
expiry = rxrpc_closed_conn_expiry * HZ;
conn_expires_at = conn->idle_timestamp + expiry;
now = READ_ONCE(jiffies);
if (time_after(conn_expires_at, now))
goto not_yet_expired;
}
trace_rxrpc_client(conn, -1, rxrpc_client_discard);
list_del_init(&conn->cache_link);
spin_unlock(&rxnet->client_conn_cache_lock);
rxrpc_unbundle_conn(conn);
rxrpc_put_connection(conn); /* Drop the ->cache_link ref */
nr_conns--;
goto next;
not_yet_expired:
/* The connection at the front of the queue hasn't yet expired, so
* schedule the work item for that point if we discarded something.
*
* We don't worry if the work item is already scheduled - it can look
* after rescheduling itself at a later time. We could cancel it, but
* then things get messier.
*/
_debug("not yet");
if (!rxnet->kill_all_client_conns)
timer_reduce(&rxnet->client_conn_reap_timer, conn_expires_at);
out:
spin_unlock(&rxnet->client_conn_cache_lock);
spin_unlock(&rxnet->client_conn_discard_lock);
_leave("");
}
/*
* Preemptively destroy all the client connection records rather than waiting
* for them to time out
*/
void rxrpc_destroy_all_client_connections(struct rxrpc_net *rxnet)
{
_enter("");
spin_lock(&rxnet->client_conn_cache_lock);
rxnet->kill_all_client_conns = true;
spin_unlock(&rxnet->client_conn_cache_lock);
del_timer_sync(&rxnet->client_conn_reap_timer);
if (!rxrpc_queue_work(&rxnet->client_conn_reaper))
_debug("destroy: queue failed");
_leave("");
}
/*
* Clean up the client connections on a local endpoint.
*/
void rxrpc_clean_up_local_conns(struct rxrpc_local *local)
{
struct rxrpc_connection *conn, *tmp;
struct rxrpc_net *rxnet = local->rxnet;
LIST_HEAD(graveyard);
_enter("");
spin_lock(&rxnet->client_conn_cache_lock);
list_for_each_entry_safe(conn, tmp, &rxnet->idle_client_conns,
cache_link) {
if (conn->params.local == local) {
trace_rxrpc_client(conn, -1, rxrpc_client_discard);
list_move(&conn->cache_link, &graveyard);
}
}
spin_unlock(&rxnet->client_conn_cache_lock);
while (!list_empty(&graveyard)) {
conn = list_entry(graveyard.next,
struct rxrpc_connection, cache_link);
list_del_init(&conn->cache_link);
rxrpc_unbundle_conn(conn);
rxrpc_put_connection(conn);
}
_leave(" [culled]");
}
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