forked from Minki/linux
999b69f892
Kill off the concept of maintaining a bundle of connections to a particular target service to increase the number of call slots available for any beyond four for that service (there are four call slots per connection). This will make cleaning up the connection handling code easier and facilitate removal of the rxrpc_transport struct. Bundling can be reintroduced later if necessary. Signed-off-by: David Howells <dhowells@redhat.com>
95 lines
2.7 KiB
C
95 lines
2.7 KiB
C
/* Client connection-specific management code.
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*
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* Copyright (C) 2016 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/slab.h>
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#include <linux/idr.h>
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#include <linux/timer.h>
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#include "ar-internal.h"
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/*
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* We use machine-unique IDs for our client connections.
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*/
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DEFINE_IDR(rxrpc_client_conn_ids);
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static DEFINE_SPINLOCK(rxrpc_conn_id_lock);
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/*
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* Get a connection ID and epoch for a client connection from the global pool.
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* The connection struct pointer is then recorded in the idr radix tree. The
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* epoch is changed if this wraps.
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*
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* TODO: The IDR tree gets very expensive on memory if the connection IDs are
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* widely scattered throughout the number space, so we shall need to retire
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* connections that have, say, an ID more than four times the maximum number of
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* client conns away from the current allocation point to try and keep the IDs
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* concentrated. We will also need to retire connections from an old epoch.
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*/
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int rxrpc_get_client_connection_id(struct rxrpc_connection *conn, gfp_t gfp)
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{
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u32 epoch;
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int id;
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_enter("");
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idr_preload(gfp);
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spin_lock(&rxrpc_conn_id_lock);
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epoch = rxrpc_epoch;
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/* We could use idr_alloc_cyclic() here, but we really need to know
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* when the thing wraps so that we can advance the epoch.
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*/
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if (rxrpc_client_conn_ids.cur == 0)
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rxrpc_client_conn_ids.cur = 1;
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id = idr_alloc(&rxrpc_client_conn_ids, conn,
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rxrpc_client_conn_ids.cur, 0x40000000, GFP_NOWAIT);
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if (id < 0) {
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if (id != -ENOSPC)
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goto error;
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id = idr_alloc(&rxrpc_client_conn_ids, conn,
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1, 0x40000000, GFP_NOWAIT);
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if (id < 0)
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goto error;
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epoch++;
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rxrpc_epoch = epoch;
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}
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rxrpc_client_conn_ids.cur = id + 1;
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spin_unlock(&rxrpc_conn_id_lock);
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idr_preload_end();
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conn->proto.epoch = epoch;
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conn->proto.cid = id << RXRPC_CIDSHIFT;
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set_bit(RXRPC_CONN_HAS_IDR, &conn->flags);
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_leave(" [CID %x:%x]", epoch, conn->proto.cid);
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return 0;
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error:
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spin_unlock(&rxrpc_conn_id_lock);
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idr_preload_end();
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_leave(" = %d", id);
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return id;
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}
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/*
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* Release a connection ID for a client connection from the global pool.
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*/
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void rxrpc_put_client_connection_id(struct rxrpc_connection *conn)
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{
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if (test_bit(RXRPC_CONN_HAS_IDR, &conn->flags)) {
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spin_lock(&rxrpc_conn_id_lock);
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idr_remove(&rxrpc_client_conn_ids,
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conn->proto.cid >> RXRPC_CIDSHIFT);
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spin_unlock(&rxrpc_conn_id_lock);
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}
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}
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