X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=kernel%2Fnet%2Frxrpc%2Far-transport.c;fp=kernel%2Fnet%2Frxrpc%2Far-transport.c;h=1976dec84f297cfb126df6bcd53129f1d518001b;hb=9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00;hp=0000000000000000000000000000000000000000;hpb=98260f3884f4a202f9ca5eabed40b1354c489b29;p=kvmfornfv.git diff --git a/kernel/net/rxrpc/ar-transport.c b/kernel/net/rxrpc/ar-transport.c new file mode 100644 index 000000000..1976dec84 --- /dev/null +++ b/kernel/net/rxrpc/ar-transport.c @@ -0,0 +1,283 @@ +/* RxRPC point-to-point transport session management + * + * Copyright (C) 2007 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 License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include +#include +#include +#include +#include +#include +#include "ar-internal.h" + +/* + * Time after last use at which transport record is cleaned up. + */ +unsigned rxrpc_transport_expiry = 3600 * 24; + +static void rxrpc_transport_reaper(struct work_struct *work); + +static LIST_HEAD(rxrpc_transports); +static DEFINE_RWLOCK(rxrpc_transport_lock); +static DECLARE_DELAYED_WORK(rxrpc_transport_reap, rxrpc_transport_reaper); + +/* + * allocate a new transport session manager + */ +static struct rxrpc_transport *rxrpc_alloc_transport(struct rxrpc_local *local, + struct rxrpc_peer *peer, + gfp_t gfp) +{ + struct rxrpc_transport *trans; + + _enter(""); + + trans = kzalloc(sizeof(struct rxrpc_transport), gfp); + if (trans) { + trans->local = local; + trans->peer = peer; + INIT_LIST_HEAD(&trans->link); + trans->bundles = RB_ROOT; + trans->client_conns = RB_ROOT; + trans->server_conns = RB_ROOT; + skb_queue_head_init(&trans->error_queue); + spin_lock_init(&trans->client_lock); + rwlock_init(&trans->conn_lock); + atomic_set(&trans->usage, 1); + trans->debug_id = atomic_inc_return(&rxrpc_debug_id); + + if (peer->srx.transport.family == AF_INET) { + switch (peer->srx.transport_type) { + case SOCK_DGRAM: + INIT_WORK(&trans->error_handler, + rxrpc_UDP_error_handler); + break; + default: + BUG(); + break; + } + } else { + BUG(); + } + } + + _leave(" = %p", trans); + return trans; +} + +/* + * obtain a transport session for the nominated endpoints + */ +struct rxrpc_transport *rxrpc_get_transport(struct rxrpc_local *local, + struct rxrpc_peer *peer, + gfp_t gfp) +{ + struct rxrpc_transport *trans, *candidate; + const char *new = "old"; + int usage; + + _enter("{%pI4+%hu},{%pI4+%hu},", + &local->srx.transport.sin.sin_addr, + ntohs(local->srx.transport.sin.sin_port), + &peer->srx.transport.sin.sin_addr, + ntohs(peer->srx.transport.sin.sin_port)); + + /* search the transport list first */ + read_lock_bh(&rxrpc_transport_lock); + list_for_each_entry(trans, &rxrpc_transports, link) { + if (trans->local == local && trans->peer == peer) + goto found_extant_transport; + } + read_unlock_bh(&rxrpc_transport_lock); + + /* not yet present - create a candidate for a new record and then + * redo the search */ + candidate = rxrpc_alloc_transport(local, peer, gfp); + if (!candidate) { + _leave(" = -ENOMEM"); + return ERR_PTR(-ENOMEM); + } + + write_lock_bh(&rxrpc_transport_lock); + + list_for_each_entry(trans, &rxrpc_transports, link) { + if (trans->local == local && trans->peer == peer) + goto found_extant_second; + } + + /* we can now add the new candidate to the list */ + trans = candidate; + candidate = NULL; + usage = atomic_read(&trans->usage); + + rxrpc_get_local(trans->local); + atomic_inc(&trans->peer->usage); + list_add_tail(&trans->link, &rxrpc_transports); + write_unlock_bh(&rxrpc_transport_lock); + new = "new"; + +success: + _net("TRANSPORT %s %d local %d -> peer %d", + new, + trans->debug_id, + trans->local->debug_id, + trans->peer->debug_id); + + _leave(" = %p {u=%d}", trans, usage); + return trans; + + /* we found the transport in the list immediately */ +found_extant_transport: + usage = atomic_inc_return(&trans->usage); + read_unlock_bh(&rxrpc_transport_lock); + goto success; + + /* we found the transport on the second time through the list */ +found_extant_second: + usage = atomic_inc_return(&trans->usage); + write_unlock_bh(&rxrpc_transport_lock); + kfree(candidate); + goto success; +} + +/* + * find the transport connecting two endpoints + */ +struct rxrpc_transport *rxrpc_find_transport(struct rxrpc_local *local, + struct rxrpc_peer *peer) +{ + struct rxrpc_transport *trans; + + _enter("{%pI4+%hu},{%pI4+%hu},", + &local->srx.transport.sin.sin_addr, + ntohs(local->srx.transport.sin.sin_port), + &peer->srx.transport.sin.sin_addr, + ntohs(peer->srx.transport.sin.sin_port)); + + /* search the transport list */ + read_lock_bh(&rxrpc_transport_lock); + + list_for_each_entry(trans, &rxrpc_transports, link) { + if (trans->local == local && trans->peer == peer) + goto found_extant_transport; + } + + read_unlock_bh(&rxrpc_transport_lock); + _leave(" = NULL"); + return NULL; + +found_extant_transport: + atomic_inc(&trans->usage); + read_unlock_bh(&rxrpc_transport_lock); + _leave(" = %p", trans); + return trans; +} + +/* + * release a transport session + */ +void rxrpc_put_transport(struct rxrpc_transport *trans) +{ + _enter("%p{u=%d}", trans, atomic_read(&trans->usage)); + + ASSERTCMP(atomic_read(&trans->usage), >, 0); + + trans->put_time = get_seconds(); + if (unlikely(atomic_dec_and_test(&trans->usage))) { + _debug("zombie"); + /* let the reaper determine the timeout to avoid a race with + * overextending the timeout if the reaper is running at the + * same time */ + rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0); + } + _leave(""); +} + +/* + * clean up a transport session + */ +static void rxrpc_cleanup_transport(struct rxrpc_transport *trans) +{ + _net("DESTROY TRANS %d", trans->debug_id); + + rxrpc_purge_queue(&trans->error_queue); + + rxrpc_put_local(trans->local); + rxrpc_put_peer(trans->peer); + kfree(trans); +} + +/* + * reap dead transports that have passed their expiry date + */ +static void rxrpc_transport_reaper(struct work_struct *work) +{ + struct rxrpc_transport *trans, *_p; + unsigned long now, earliest, reap_time; + + LIST_HEAD(graveyard); + + _enter(""); + + now = get_seconds(); + earliest = ULONG_MAX; + + /* extract all the transports that have been dead too long */ + write_lock_bh(&rxrpc_transport_lock); + list_for_each_entry_safe(trans, _p, &rxrpc_transports, link) { + _debug("reap TRANS %d { u=%d t=%ld }", + trans->debug_id, atomic_read(&trans->usage), + (long) now - (long) trans->put_time); + + if (likely(atomic_read(&trans->usage) > 0)) + continue; + + reap_time = trans->put_time + rxrpc_transport_expiry; + if (reap_time <= now) + list_move_tail(&trans->link, &graveyard); + else if (reap_time < earliest) + earliest = reap_time; + } + write_unlock_bh(&rxrpc_transport_lock); + + if (earliest != ULONG_MAX) { + _debug("reschedule reaper %ld", (long) earliest - now); + ASSERTCMP(earliest, >, now); + rxrpc_queue_delayed_work(&rxrpc_transport_reap, + (earliest - now) * HZ); + } + + /* then destroy all those pulled out */ + while (!list_empty(&graveyard)) { + trans = list_entry(graveyard.next, struct rxrpc_transport, + link); + list_del_init(&trans->link); + + ASSERTCMP(atomic_read(&trans->usage), ==, 0); + rxrpc_cleanup_transport(trans); + } + + _leave(""); +} + +/* + * preemptively destroy all the transport session records rather than waiting + * for them to time out + */ +void __exit rxrpc_destroy_all_transports(void) +{ + _enter(""); + + rxrpc_transport_expiry = 0; + cancel_delayed_work(&rxrpc_transport_reap); + rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0); + + _leave(""); +}