| /* Client connection-specific management code. |
| * |
| * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved. |
| * Written by David Howells (dhowells@redhat.com) |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public Licence |
| * as published by the Free Software Foundation; either version |
| * 2 of the Licence, or (at your option) any later version. |
| * |
| * |
| * 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. |
| * |
| * Client connections can be in one of a number of cache states: |
| * |
| * (1) INACTIVE - The connection is not held in any list and may not have been |
| * exposed to the world. If it has been previously exposed, it was |
| * discarded from the idle list after expiring. |
| * |
| * (2) WAITING - The connection is waiting for the number of client conns to |
| * drop below the maximum capacity. Calls may be in progress upon it from |
| * when it was active and got culled. |
| * |
| * The connection is on the rxrpc_waiting_client_conns list which is kept |
| * in to-be-granted order. Culled conns with waiters go to the back of |
| * the queue just like new conns. |
| * |
| * (3) ACTIVE - The connection has at least one call in progress upon it, it |
| * may freely grant available channels to new calls and calls may be |
| * waiting on it for channels to become available. |
| * |
| * The connection is on the rxrpc_active_client_conns list which is kept |
| * in activation order for culling purposes. |
| * |
| * rxrpc_nr_active_client_conns is held incremented also. |
| * |
| * (4) CULLED - The connection got summarily culled to try and free up |
| * capacity. Calls currently in progress on the connection are allowed to |
| * continue, but new calls will have to wait. There can be no waiters in |
| * this state - the conn would have to go to the WAITING state instead. |
| * |
| * (5) IDLE - The connection has no calls in progress upon it and must have |
| * been exposed to the world (ie. the EXPOSED flag must be set). When it |
| * expires, the EXPOSED flag is cleared and the connection transitions to |
| * the INACTIVE state. |
| * |
| * The connection is on the rxrpc_idle_client_conns list which is kept in |
| * order of how soon they'll expire. |
| * |
| * There are flags of relevance to the cache: |
| * |
| * (1) EXPOSED - The connection ID got exposed to the world. If this flag is |
| * set, an extra ref is added to the connection preventing it from being |
| * reaped when it has no calls outstanding. This flag is cleared and the |
| * ref dropped when a conn is discarded from the idle list. |
| * |
| * This allows us to move terminal call state retransmission to the |
| * connection and to discard the call immediately we think it is done |
| * with. It also give us a chance to reuse the connection. |
| * |
| * (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 "ar-internal.h" |
| |
| __read_mostly unsigned int rxrpc_max_client_connections = 1000; |
| __read_mostly unsigned int rxrpc_reap_client_connections = 900; |
| __read_mostly unsigned int rxrpc_conn_idle_client_expiry = 2 * 60 * HZ; |
| __read_mostly unsigned int rxrpc_conn_idle_client_fast_expiry = 2 * HZ; |
| |
| static unsigned int rxrpc_nr_client_conns; |
| static unsigned int rxrpc_nr_active_client_conns; |
| static __read_mostly bool rxrpc_kill_all_client_conns; |
| |
| static DEFINE_SPINLOCK(rxrpc_client_conn_cache_lock); |
| static DEFINE_SPINLOCK(rxrpc_client_conn_discard_mutex); |
| static LIST_HEAD(rxrpc_waiting_client_conns); |
| static LIST_HEAD(rxrpc_active_client_conns); |
| static LIST_HEAD(rxrpc_idle_client_conns); |
| |
| /* |
| * We use machine-unique IDs for our client connections. |
| */ |
| DEFINE_IDR(rxrpc_client_conn_ids); |
| static DEFINE_SPINLOCK(rxrpc_conn_id_lock); |
| |
| static void rxrpc_cull_active_client_conns(void); |
| static void rxrpc_discard_expired_client_conns(struct work_struct *); |
| |
| static DECLARE_DELAYED_WORK(rxrpc_client_conn_reap, |
| rxrpc_discard_expired_client_conns); |
| |
| const char rxrpc_conn_cache_states[RXRPC_CONN__NR_CACHE_STATES][5] = { |
| [RXRPC_CONN_CLIENT_INACTIVE] = "Inac", |
| [RXRPC_CONN_CLIENT_WAITING] = "Wait", |
| [RXRPC_CONN_CLIENT_ACTIVE] = "Actv", |
| [RXRPC_CONN_CLIENT_CULLED] = "Cull", |
| [RXRPC_CONN_CLIENT_IDLE] = "Idle", |
| }; |
| |
| /* |
| * 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) |
| { |
| 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 = rxrpc_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, atomic_read(&conn->usage)); |
| } |
| BUG(); |
| } |
| |
| idr_destroy(&rxrpc_client_conn_ids); |
| } |
| |
| /* |
| * Allocate a client connection. |
| */ |
| static struct rxrpc_connection * |
| rxrpc_alloc_client_connection(struct rxrpc_conn_parameters *cp, gfp_t gfp) |
| { |
| struct rxrpc_connection *conn; |
| int ret; |
| |
| _enter(""); |
| |
| conn = rxrpc_alloc_connection(gfp); |
| if (!conn) { |
| _leave(" = -ENOMEM"); |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| atomic_set(&conn->usage, 1); |
| if (cp->exclusive) |
| __set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags); |
| |
| conn->params = *cp; |
| conn->out_clientflag = RXRPC_CLIENT_INITIATED; |
| conn->state = RXRPC_CONN_CLIENT; |
| |
| 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; |
| |
| ret = conn->security->prime_packet_security(conn); |
| if (ret < 0) |
| goto error_2; |
| |
| write_lock(&rxrpc_connection_lock); |
| list_add_tail(&conn->proc_link, &rxrpc_connection_proc_list); |
| write_unlock(&rxrpc_connection_lock); |
| |
| /* We steal the caller's peer ref. */ |
| cp->peer = NULL; |
| rxrpc_get_local(conn->params.local); |
| key_get(conn->params.key); |
| |
| trace_rxrpc_conn(conn, rxrpc_conn_new_client, atomic_read(&conn->usage), |
| __builtin_return_address(0)); |
| trace_rxrpc_client(conn, -1, rxrpc_client_alloc); |
| _leave(" = %p", conn); |
| return conn; |
| |
| error_2: |
| conn->security->clear(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) |
| { |
| int id_cursor, id, distance, limit; |
| |
| if (test_bit(RXRPC_CONN_DONT_REUSE, &conn->flags)) |
| goto dont_reuse; |
| |
| if (conn->proto.epoch != rxrpc_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 = READ_ONCE(rxrpc_client_conn_ids.cur); |
| id = conn->proto.cid >> RXRPC_CIDSHIFT; |
| distance = id - id_cursor; |
| if (distance < 0) |
| distance = -distance; |
| limit = round_up(rxrpc_max_client_connections, IDR_SIZE) * 4; |
| if (distance > limit) |
| goto mark_dont_reuse; |
| |
| return true; |
| |
| mark_dont_reuse: |
| set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags); |
| dont_reuse: |
| return false; |
| } |
| |
| /* |
| * Create or find a client connection 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 int rxrpc_get_client_conn(struct rxrpc_call *call, |
| struct rxrpc_conn_parameters *cp, |
| struct sockaddr_rxrpc *srx, |
| gfp_t gfp) |
| { |
| struct rxrpc_connection *conn, *candidate = NULL; |
| struct rxrpc_local *local = cp->local; |
| struct rb_node *p, **pp, *parent; |
| long diff; |
| int ret = -ENOMEM; |
| |
| _enter("{%d,%lx},", call->debug_id, call->user_call_ID); |
| |
| cp->peer = rxrpc_lookup_peer(cp->local, srx, gfp); |
| if (!cp->peer) |
| goto error; |
| |
| /* If the connection is not meant to be exclusive, search the available |
| * connections to see if the connection we want to use already exists. |
| */ |
| if (!cp->exclusive) { |
| _debug("search 1"); |
| spin_lock(&local->client_conns_lock); |
| p = local->client_conns.rb_node; |
| while (p) { |
| conn = rb_entry(p, struct rxrpc_connection, client_node); |
| |
| #define cmp(X) ((long)conn->params.X - (long)cp->X) |
| diff = (cmp(peer) ?: |
| cmp(key) ?: |
| cmp(security_level)); |
| #undef cmp |
| if (diff < 0) { |
| p = p->rb_left; |
| } else if (diff > 0) { |
| p = p->rb_right; |
| } else { |
| if (rxrpc_may_reuse_conn(conn) && |
| rxrpc_get_connection_maybe(conn)) |
| goto found_extant_conn; |
| /* The connection needs replacing. It's better |
| * to effect that when we have something to |
| * replace it with so that we don't have to |
| * rebalance the tree twice. |
| */ |
| break; |
| } |
| } |
| spin_unlock(&local->client_conns_lock); |
| } |
| |
| /* There wasn't a connection yet or we need an exclusive connection. |
| * We need to create a candidate and then potentially redo the search |
| * in case we're racing with another thread also trying to connect on a |
| * shareable connection. |
| */ |
| _debug("new conn"); |
| candidate = rxrpc_alloc_client_connection(cp, gfp); |
| if (IS_ERR(candidate)) { |
| ret = PTR_ERR(candidate); |
| goto error_peer; |
| } |
| |
| /* Add the call to the new connection's waiting list in case we're |
| * going to have to wait for the connection to come live. It's our |
| * connection, so we want first dibs on the channel slots. We would |
| * normally have to take channel_lock but we do this before anyone else |
| * can see the connection. |
| */ |
| list_add(&call->chan_wait_link, &candidate->waiting_calls); |
| |
| if (cp->exclusive) { |
| call->conn = candidate; |
| call->security_ix = candidate->security_ix; |
| _leave(" = 0 [exclusive %d]", candidate->debug_id); |
| return 0; |
| } |
| |
| /* Publish the new connection for userspace to find. We need to redo |
| * the search before doing this lest we race with someone else adding a |
| * conflicting instance. |
| */ |
| _debug("search 2"); |
| spin_lock(&local->client_conns_lock); |
| |
| pp = &local->client_conns.rb_node; |
| parent = NULL; |
| while (*pp) { |
| parent = *pp; |
| conn = rb_entry(parent, struct rxrpc_connection, client_node); |
| |
| #define cmp(X) ((long)conn->params.X - (long)candidate->params.X) |
| diff = (cmp(peer) ?: |
| cmp(key) ?: |
| cmp(security_level)); |
| #undef cmp |
| if (diff < 0) { |
| pp = &(*pp)->rb_left; |
| } else if (diff > 0) { |
| pp = &(*pp)->rb_right; |
| } else { |
| if (rxrpc_may_reuse_conn(conn) && |
| rxrpc_get_connection_maybe(conn)) |
| goto found_extant_conn; |
| /* The old connection is from an outdated epoch. */ |
| _debug("replace conn"); |
| clear_bit(RXRPC_CONN_IN_CLIENT_CONNS, &conn->flags); |
| rb_replace_node(&conn->client_node, |
| &candidate->client_node, |
| &local->client_conns); |
| trace_rxrpc_client(conn, -1, rxrpc_client_replace); |
| goto candidate_published; |
| } |
| } |
| |
| _debug("new conn"); |
| rb_link_node(&candidate->client_node, parent, pp); |
| rb_insert_color(&candidate->client_node, &local->client_conns); |
| |
| candidate_published: |
| set_bit(RXRPC_CONN_IN_CLIENT_CONNS, &candidate->flags); |
| call->conn = candidate; |
| call->security_ix = candidate->security_ix; |
| spin_unlock(&local->client_conns_lock); |
| _leave(" = 0 [new %d]", candidate->debug_id); |
| return 0; |
| |
| /* We come here if we found a suitable connection already in existence. |
| * Discard any candidate we may have allocated, and try to get a |
| * channel on this one. |
| */ |
| found_extant_conn: |
| _debug("found conn"); |
| spin_unlock(&local->client_conns_lock); |
| |
| if (candidate) { |
| trace_rxrpc_client(candidate, -1, rxrpc_client_duplicate); |
| rxrpc_put_connection(candidate); |
| candidate = NULL; |
| } |
| |
| spin_lock(&conn->channel_lock); |
| call->conn = conn; |
| call->security_ix = conn->security_ix; |
| list_add_tail(&call->chan_wait_link, &conn->waiting_calls); |
| spin_unlock(&conn->channel_lock); |
| _leave(" = 0 [extant %d]", conn->debug_id); |
| return 0; |
| |
| error_peer: |
| rxrpc_put_peer(cp->peer); |
| cp->peer = NULL; |
| error: |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| /* |
| * Activate a connection. |
| */ |
| static void rxrpc_activate_conn(struct rxrpc_connection *conn) |
| { |
| trace_rxrpc_client(conn, -1, rxrpc_client_to_active); |
| conn->cache_state = RXRPC_CONN_CLIENT_ACTIVE; |
| rxrpc_nr_active_client_conns++; |
| list_move_tail(&conn->cache_link, &rxrpc_active_client_conns); |
| } |
| |
| /* |
| * Attempt to animate a connection for a new call. |
| * |
| * If it's not exclusive, the connection is in the endpoint tree, and we're in |
| * the conn's list of those waiting to grab a channel. There is, however, a |
| * limit on the number of live connections allowed at any one time, so we may |
| * have to wait for capacity to become available. |
| * |
| * Note that a connection on the waiting queue might *also* have active |
| * channels if it has been culled to make space and then re-requested by a new |
| * call. |
| */ |
| static void rxrpc_animate_client_conn(struct rxrpc_connection *conn) |
| { |
| unsigned int nr_conns; |
| |
| _enter("%d,%d", conn->debug_id, conn->cache_state); |
| |
| if (conn->cache_state == RXRPC_CONN_CLIENT_ACTIVE) |
| goto out; |
| |
| spin_lock(&rxrpc_client_conn_cache_lock); |
| |
| nr_conns = rxrpc_nr_client_conns; |
| if (!test_and_set_bit(RXRPC_CONN_COUNTED, &conn->flags)) { |
| trace_rxrpc_client(conn, -1, rxrpc_client_count); |
| rxrpc_nr_client_conns = nr_conns + 1; |
| } |
| |
| switch (conn->cache_state) { |
| case RXRPC_CONN_CLIENT_ACTIVE: |
| case RXRPC_CONN_CLIENT_WAITING: |
| break; |
| |
| case RXRPC_CONN_CLIENT_INACTIVE: |
| case RXRPC_CONN_CLIENT_CULLED: |
| case RXRPC_CONN_CLIENT_IDLE: |
| if (nr_conns >= rxrpc_max_client_connections) |
| goto wait_for_capacity; |
| goto activate_conn; |
| |
| default: |
| BUG(); |
| } |
| |
| out_unlock: |
| spin_unlock(&rxrpc_client_conn_cache_lock); |
| out: |
| _leave(" [%d]", conn->cache_state); |
| return; |
| |
| activate_conn: |
| _debug("activate"); |
| rxrpc_activate_conn(conn); |
| goto out_unlock; |
| |
| wait_for_capacity: |
| _debug("wait"); |
| trace_rxrpc_client(conn, -1, rxrpc_client_to_waiting); |
| conn->cache_state = RXRPC_CONN_CLIENT_WAITING; |
| list_move_tail(&conn->cache_link, &rxrpc_waiting_client_conns); |
| goto out_unlock; |
| } |
| |
| /* |
| * Deactivate a channel. |
| */ |
| static void rxrpc_deactivate_one_channel(struct rxrpc_connection *conn, |
| unsigned int channel) |
| { |
| struct rxrpc_channel *chan = &conn->channels[channel]; |
| |
| rcu_assign_pointer(chan->call, NULL); |
| conn->active_chans &= ~(1 << channel); |
| } |
| |
| /* |
| * 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_call *call = list_entry(conn->waiting_calls.next, |
| struct rxrpc_call, chan_wait_link); |
| u32 call_id = chan->call_counter + 1; |
| |
| trace_rxrpc_client(conn, channel, rxrpc_client_chan_activate); |
| |
| write_lock_bh(&call->state_lock); |
| call->state = RXRPC_CALL_CLIENT_SEND_REQUEST; |
| write_unlock_bh(&call->state_lock); |
| |
| rxrpc_see_call(call); |
| list_del_init(&call->chan_wait_link); |
| conn->active_chans |= 1 << channel; |
| call->peer = rxrpc_get_peer(conn->params.peer); |
| call->cid = conn->proto.cid | channel; |
| call->call_id = call_id; |
| |
| _net("CONNECT call %08x:%08x as call %d on conn %d", |
| call->cid, call->call_id, call->debug_id, conn->debug_id); |
| |
| /* Paired with the read barrier in rxrpc_wait_for_channel(). 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; |
| rcu_assign_pointer(chan->call, call); |
| wake_up(&call->waitq); |
| } |
| |
| /* |
| * Assign channels and callNumbers to waiting calls with channel_lock |
| * held by caller. |
| */ |
| static void rxrpc_activate_channels_locked(struct rxrpc_connection *conn) |
| { |
| u8 avail, mask; |
| |
| switch (conn->cache_state) { |
| case RXRPC_CONN_CLIENT_ACTIVE: |
| mask = RXRPC_ACTIVE_CHANS_MASK; |
| break; |
| default: |
| return; |
| } |
| |
| while (!list_empty(&conn->waiting_calls) && |
| (avail = ~conn->active_chans, |
| avail &= mask, |
| avail != 0)) |
| rxrpc_activate_one_channel(conn, __ffs(avail)); |
| } |
| |
| /* |
| * Assign channels and callNumbers to waiting calls. |
| */ |
| static void rxrpc_activate_channels(struct rxrpc_connection *conn) |
| { |
| _enter("%d", conn->debug_id); |
| |
| trace_rxrpc_client(conn, -1, rxrpc_client_activate_chans); |
| |
| if (conn->active_chans == RXRPC_ACTIVE_CHANS_MASK) |
| return; |
| |
| spin_lock(&conn->channel_lock); |
| rxrpc_activate_channels_locked(conn); |
| spin_unlock(&conn->channel_lock); |
| _leave(""); |
| } |
| |
| /* |
| * Wait for a callNumber and a channel to be granted to a call. |
| */ |
| static int rxrpc_wait_for_channel(struct rxrpc_call *call, gfp_t gfp) |
| { |
| int ret = 0; |
| |
| _enter("%d", call->debug_id); |
| |
| if (!call->call_id) { |
| DECLARE_WAITQUEUE(myself, current); |
| |
| if (!gfpflags_allow_blocking(gfp)) { |
| ret = -EAGAIN; |
| goto out; |
| } |
| |
| add_wait_queue_exclusive(&call->waitq, &myself); |
| for (;;) { |
| set_current_state(TASK_INTERRUPTIBLE); |
| if (call->call_id) |
| break; |
| if (signal_pending(current)) { |
| ret = -ERESTARTSYS; |
| break; |
| } |
| schedule(); |
| } |
| remove_wait_queue(&call->waitq, &myself); |
| __set_current_state(TASK_RUNNING); |
| } |
| |
| /* Paired with the write barrier in rxrpc_activate_one_channel(). */ |
| smp_rmb(); |
| |
| 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_call *call, |
| struct rxrpc_conn_parameters *cp, |
| struct sockaddr_rxrpc *srx, |
| gfp_t gfp) |
| { |
| int ret; |
| |
| _enter("{%d,%lx},", call->debug_id, call->user_call_ID); |
| |
| rxrpc_discard_expired_client_conns(NULL); |
| rxrpc_cull_active_client_conns(); |
| |
| ret = rxrpc_get_client_conn(call, cp, srx, gfp); |
| if (ret < 0) |
| return ret; |
| |
| rxrpc_animate_client_conn(call->conn); |
| rxrpc_activate_channels(call->conn); |
| |
| ret = rxrpc_wait_for_channel(call, gfp); |
| if (ret < 0) |
| rxrpc_disconnect_client_call(call); |
| |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| /* |
| * Note that a connection is about to be exposed to the world. Once it is |
| * exposed, we maintain an extra ref on it that stops it from being summarily |
| * discarded before it's (a) had a chance to deal with retransmission and (b) |
| * had a chance at re-use (the per-connection security negotiation is |
| * expensive). |
| */ |
| static void rxrpc_expose_client_conn(struct rxrpc_connection *conn, |
| unsigned int channel) |
| { |
| if (!test_and_set_bit(RXRPC_CONN_EXPOSED, &conn->flags)) { |
| trace_rxrpc_client(conn, channel, rxrpc_client_exposed); |
| rxrpc_get_connection(conn); |
| } |
| } |
| |
| /* |
| * 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); |
| rxrpc_expose_client_conn(conn, channel); |
| } |
| } |
| |
| /* |
| * Disconnect a client call. |
| */ |
| void rxrpc_disconnect_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]; |
| |
| trace_rxrpc_client(conn, channel, rxrpc_client_chan_disconnect); |
| |
| spin_lock(&conn->channel_lock); |
| set_bit(RXRPC_CALL_DISCONNECTED, &call->flags); |
| |
| /* Calls that have never actually been assigned a channel can simply be |
| * discarded. If the conn didn't get used either, it will follow |
| * immediately unless someone else grabs it in the meantime. |
| */ |
| if (!list_empty(&call->chan_wait_link)) { |
| _debug("call is waiting"); |
| ASSERTCMP(call->call_id, ==, 0); |
| ASSERT(!test_bit(RXRPC_CALL_EXPOSED, &call->flags)); |
| list_del_init(&call->chan_wait_link); |
| |
| trace_rxrpc_client(conn, channel, rxrpc_client_chan_unstarted); |
| |
| /* We must deactivate or idle the connection if it's now |
| * waiting for nothing. |
| */ |
| spin_lock(&rxrpc_client_conn_cache_lock); |
| if (conn->cache_state == RXRPC_CONN_CLIENT_WAITING && |
| list_empty(&conn->waiting_calls) && |
| !conn->active_chans) |
| goto idle_connection; |
| goto out; |
| } |
| |
| ASSERTCMP(rcu_access_pointer(chan->call), ==, call); |
| |
| /* 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); |
| } |
| |
| /* See if we can pass the channel directly to another call. */ |
| if (conn->cache_state == RXRPC_CONN_CLIENT_ACTIVE && |
| !list_empty(&conn->waiting_calls)) { |
| trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass); |
| rxrpc_activate_one_channel(conn, channel); |
| goto out_2; |
| } |
| |
| /* Things are more complex and we need the cache lock. We might be |
| * able to simply idle the conn or it might now be lurking on the wait |
| * list. It might even get moved back to the active list whilst we're |
| * waiting for the lock. |
| */ |
| spin_lock(&rxrpc_client_conn_cache_lock); |
| |
| switch (conn->cache_state) { |
| case RXRPC_CONN_CLIENT_ACTIVE: |
| if (list_empty(&conn->waiting_calls)) { |
| rxrpc_deactivate_one_channel(conn, channel); |
| if (!conn->active_chans) { |
| rxrpc_nr_active_client_conns--; |
| goto idle_connection; |
| } |
| goto out; |
| } |
| |
| trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass); |
| rxrpc_activate_one_channel(conn, channel); |
| goto out; |
| |
| case RXRPC_CONN_CLIENT_CULLED: |
| rxrpc_deactivate_one_channel(conn, channel); |
| ASSERT(list_empty(&conn->waiting_calls)); |
| if (!conn->active_chans) |
| goto idle_connection; |
| goto out; |
| |
| case RXRPC_CONN_CLIENT_WAITING: |
| rxrpc_deactivate_one_channel(conn, channel); |
| goto out; |
| |
| default: |
| BUG(); |
| } |
| |
| out: |
| spin_unlock(&rxrpc_client_conn_cache_lock); |
| out_2: |
| spin_unlock(&conn->channel_lock); |
| _leave(""); |
| return; |
| |
| idle_connection: |
| /* As no channels remain active, the connection gets deactivated |
| * immediately or moved to the idle list for a short while. |
| */ |
| if (test_bit(RXRPC_CONN_EXPOSED, &conn->flags)) { |
| trace_rxrpc_client(conn, channel, rxrpc_client_to_idle); |
| conn->idle_timestamp = jiffies; |
| conn->cache_state = RXRPC_CONN_CLIENT_IDLE; |
| list_move_tail(&conn->cache_link, &rxrpc_idle_client_conns); |
| if (rxrpc_idle_client_conns.next == &conn->cache_link && |
| !rxrpc_kill_all_client_conns) |
| queue_delayed_work(rxrpc_workqueue, |
| &rxrpc_client_conn_reap, |
| rxrpc_conn_idle_client_expiry); |
| } else { |
| trace_rxrpc_client(conn, channel, rxrpc_client_to_inactive); |
| conn->cache_state = RXRPC_CONN_CLIENT_INACTIVE; |
| list_del_init(&conn->cache_link); |
| } |
| goto out; |
| } |
| |
| /* |
| * Clean up a dead client connection. |
| */ |
| static struct rxrpc_connection * |
| rxrpc_put_one_client_conn(struct rxrpc_connection *conn) |
| { |
| struct rxrpc_connection *next = NULL; |
| struct rxrpc_local *local = conn->params.local; |
| unsigned int nr_conns; |
| |
| trace_rxrpc_client(conn, -1, rxrpc_client_cleanup); |
| |
| if (test_bit(RXRPC_CONN_IN_CLIENT_CONNS, &conn->flags)) { |
| spin_lock(&local->client_conns_lock); |
| if (test_and_clear_bit(RXRPC_CONN_IN_CLIENT_CONNS, |
| &conn->flags)) |
| rb_erase(&conn->client_node, &local->client_conns); |
| spin_unlock(&local->client_conns_lock); |
| } |
| |
| rxrpc_put_client_connection_id(conn); |
| |
| ASSERTCMP(conn->cache_state, ==, RXRPC_CONN_CLIENT_INACTIVE); |
| |
| if (test_bit(RXRPC_CONN_COUNTED, &conn->flags)) { |
| trace_rxrpc_client(conn, -1, rxrpc_client_uncount); |
| spin_lock(&rxrpc_client_conn_cache_lock); |
| nr_conns = --rxrpc_nr_client_conns; |
| |
| if (nr_conns < rxrpc_max_client_connections && |
| !list_empty(&rxrpc_waiting_client_conns)) { |
| next = list_entry(rxrpc_waiting_client_conns.next, |
| struct rxrpc_connection, cache_link); |
| rxrpc_get_connection(next); |
| rxrpc_activate_conn(next); |
| } |
| |
| spin_unlock(&rxrpc_client_conn_cache_lock); |
| } |
| |
| rxrpc_kill_connection(conn); |
| if (next) |
| rxrpc_activate_channels(next); |
| |
| /* We need to get rid of the temporary ref we took upon next, but we |
| * can't call rxrpc_put_connection() recursively. |
| */ |
| return next; |
| } |
| |
| /* |
| * Clean up a dead client connections. |
| */ |
| void rxrpc_put_client_conn(struct rxrpc_connection *conn) |
| { |
| const void *here = __builtin_return_address(0); |
| int n; |
| |
| do { |
| n = atomic_dec_return(&conn->usage); |
| trace_rxrpc_conn(conn, rxrpc_conn_put_client, n, here); |
| if (n > 0) |
| return; |
| ASSERTCMP(n, >=, 0); |
| |
| conn = rxrpc_put_one_client_conn(conn); |
| } while (conn); |
| } |
| |
| /* |
| * Kill the longest-active client connections to make room for new ones. |
| */ |
| static void rxrpc_cull_active_client_conns(void) |
| { |
| struct rxrpc_connection *conn; |
| unsigned int nr_conns = rxrpc_nr_client_conns; |
| unsigned int nr_active, limit; |
| |
| _enter(""); |
| |
| ASSERTCMP(nr_conns, >=, 0); |
| if (nr_conns < rxrpc_max_client_connections) { |
| _leave(" [ok]"); |
| return; |
| } |
| limit = rxrpc_reap_client_connections; |
| |
| spin_lock(&rxrpc_client_conn_cache_lock); |
| nr_active = rxrpc_nr_active_client_conns; |
| |
| while (nr_active > limit) { |
| ASSERT(!list_empty(&rxrpc_active_client_conns)); |
| conn = list_entry(rxrpc_active_client_conns.next, |
| struct rxrpc_connection, cache_link); |
| ASSERTCMP(conn->cache_state, ==, RXRPC_CONN_CLIENT_ACTIVE); |
| |
| if (list_empty(&conn->waiting_calls)) { |
| trace_rxrpc_client(conn, -1, rxrpc_client_to_culled); |
| conn->cache_state = RXRPC_CONN_CLIENT_CULLED; |
| list_del_init(&conn->cache_link); |
| } else { |
| trace_rxrpc_client(conn, -1, rxrpc_client_to_waiting); |
| conn->cache_state = RXRPC_CONN_CLIENT_WAITING; |
| list_move_tail(&conn->cache_link, |
| &rxrpc_waiting_client_conns); |
| } |
| |
| nr_active--; |
| } |
| |
| rxrpc_nr_active_client_conns = nr_active; |
| spin_unlock(&rxrpc_client_conn_cache_lock); |
| ASSERTCMP(nr_active, >=, 0); |
| _leave(" [culled]"); |
| } |
| |
| /* |
| * 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. |
| */ |
| static void rxrpc_discard_expired_client_conns(struct work_struct *work) |
| { |
| struct rxrpc_connection *conn; |
| unsigned long expiry, conn_expires_at, now; |
| unsigned int nr_conns; |
| bool did_discard = false; |
| |
| _enter("%c", work ? 'w' : 'n'); |
| |
| if (list_empty(&rxrpc_idle_client_conns)) { |
| _leave(" [empty]"); |
| return; |
| } |
| |
| /* Don't double up on the discarding */ |
| if (!spin_trylock(&rxrpc_client_conn_discard_mutex)) { |
| _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 = rxrpc_nr_client_conns; |
| |
| next: |
| spin_lock(&rxrpc_client_conn_cache_lock); |
| |
| if (list_empty(&rxrpc_idle_client_conns)) |
| goto out; |
| |
| conn = list_entry(rxrpc_idle_client_conns.next, |
| struct rxrpc_connection, cache_link); |
| ASSERT(test_bit(RXRPC_CONN_EXPOSED, &conn->flags)); |
| |
| if (!rxrpc_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; |
| |
| 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); |
| if (!test_and_clear_bit(RXRPC_CONN_EXPOSED, &conn->flags)) |
| BUG(); |
| conn->cache_state = RXRPC_CONN_CLIENT_INACTIVE; |
| list_del_init(&conn->cache_link); |
| |
| spin_unlock(&rxrpc_client_conn_cache_lock); |
| |
| /* When we cleared the EXPOSED flag, we took on responsibility for the |
| * reference that that had on the usage count. We deal with that here. |
| * If someone re-sets the flag and re-gets the ref, that's fine. |
| */ |
| rxrpc_put_connection(conn); |
| did_discard = true; |
| 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 (!rxrpc_kill_all_client_conns) |
| queue_delayed_work(rxrpc_workqueue, |
| &rxrpc_client_conn_reap, |
| conn_expires_at - now); |
| |
| out: |
| spin_unlock(&rxrpc_client_conn_cache_lock); |
| spin_unlock(&rxrpc_client_conn_discard_mutex); |
| _leave(""); |
| } |
| |
| /* |
| * Preemptively destroy all the client connection records rather than waiting |
| * for them to time out |
| */ |
| void __exit rxrpc_destroy_all_client_connections(void) |
| { |
| _enter(""); |
| |
| spin_lock(&rxrpc_client_conn_cache_lock); |
| rxrpc_kill_all_client_conns = true; |
| spin_unlock(&rxrpc_client_conn_cache_lock); |
| |
| cancel_delayed_work(&rxrpc_client_conn_reap); |
| |
| if (!queue_delayed_work(rxrpc_workqueue, &rxrpc_client_conn_reap, 0)) |
| _debug("destroy: queue failed"); |
| |
| _leave(""); |
| } |