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// SPDX-License-Identifier: GPL-2.0
/*
* GPL HEADER START
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 only,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License version 2 for more details (a copy is included
* in the LICENSE file that accompanied this code).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; If not, see
* http://www.gnu.org/licenses/gpl-2.0.html
*
* GPL HEADER END
*/
/*
* Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
* Use is subject to license terms.
*
* Copyright (c) 2011, Intel Corporation.
*/
/*
* This file is part of Lustre, http://www.lustre.org/
* Lustre is a trademark of Sun Microsystems, Inc.
*/
#define DEBUG_SUBSYSTEM S_RPC
#include <obd_support.h>
#include <obd_class.h>
#include <lustre_net.h>
#include "ptlrpc_internal.h"
static struct rhashtable conn_hash;
/*
* struct lnet_process_id may contain unassigned bytes which might not
* be zero, so we cannot just hash and compare bytes.
*/
static u32 lnet_process_id_hash(const void *data, u32 len, u32 seed)
{
const struct lnet_process_id *lpi = data;
seed = hash_32(seed ^ lpi->pid, 32);
seed ^= hash_64(lpi->nid, 32);
return seed;
}
static int lnet_process_id_cmp(struct rhashtable_compare_arg *arg,
const void *obj)
{
const struct lnet_process_id *lpi = arg->key;
const struct ptlrpc_connection *con = obj;
if (lpi->nid == con->c_peer.nid &&
lpi->pid == con->c_peer.pid)
return 0;
return -ESRCH;
}
static const struct rhashtable_params conn_hash_params = {
.key_len = 1, /* actually variable-length */
.key_offset = offsetof(struct ptlrpc_connection, c_peer),
.head_offset = offsetof(struct ptlrpc_connection, c_hash),
.hashfn = lnet_process_id_hash,
.obj_cmpfn = lnet_process_id_cmp,
};
struct ptlrpc_connection *
ptlrpc_connection_get(struct lnet_process_id peer, lnet_nid_t self,
struct obd_uuid *uuid)
{
struct ptlrpc_connection *conn, *conn2;
conn = rhashtable_lookup_fast(&conn_hash, &peer, conn_hash_params);
if (conn) {
ptlrpc_connection_addref(conn);
goto out;
}
conn = kzalloc(sizeof(*conn), GFP_NOFS);
if (!conn)
return NULL;
conn->c_peer = peer;
conn->c_self = self;
atomic_set(&conn->c_refcount, 1);
if (uuid)
obd_str2uuid(&conn->c_remote_uuid, uuid->uuid);
/*
* Add the newly created conn to the hash, on key collision we
* lost a racing addition and must destroy our newly allocated
* connection. The object which exists in the hash will be
* returned, otherwise NULL is returned on success.
*/
conn2 = rhashtable_lookup_get_insert_fast(&conn_hash, &conn->c_hash,
conn_hash_params);
if (conn2 != NULL) {
/* insertion failed */
kfree(conn);
if (IS_ERR(conn2))
return NULL;
conn = conn2;
ptlrpc_connection_addref(conn);
}
out:
CDEBUG(D_INFO, "conn=%p refcount %d to %s\n",
conn, atomic_read(&conn->c_refcount),
libcfs_nid2str(conn->c_peer.nid));
return conn;
}
int ptlrpc_connection_put(struct ptlrpc_connection *conn)
{
int rc = 0;
if (!conn)
return rc;
LASSERT(atomic_read(&conn->c_refcount) > 0);
/*
* We do not remove connection from hashtable and
* do not free it even if last caller released ref,
* as we want to have it cached for the case it is
* needed again.
*
* Deallocating it and later creating new connection
* again would be wastful. This way we also avoid
* expensive locking to protect things from get/put
* race when found cached connection is freed by
* ptlrpc_connection_put().
*
* It will be freed later in module unload time,
* when ptlrpc_connection_fini()->lh_exit->conn_exit()
* path is called.
*/
if (atomic_dec_return(&conn->c_refcount) == 0)
rc = 1;
CDEBUG(D_INFO, "PUT conn=%p refcount %d to %s\n",
conn, atomic_read(&conn->c_refcount),
libcfs_nid2str(conn->c_peer.nid));
return rc;
}
struct ptlrpc_connection *
ptlrpc_connection_addref(struct ptlrpc_connection *conn)
{
atomic_inc(&conn->c_refcount);
CDEBUG(D_INFO, "conn=%p refcount %d to %s\n",
conn, atomic_read(&conn->c_refcount),
libcfs_nid2str(conn->c_peer.nid));
return conn;
}
static void
conn_exit(void *vconn, void *data)
{
struct ptlrpc_connection *conn = vconn;
/*
* Nothing should be left. Connection user put it and
* connection also was deleted from table by this time
* so we should have 0 refs.
*/
LASSERTF(atomic_read(&conn->c_refcount) == 0,
"Busy connection with %d refs\n",
atomic_read(&conn->c_refcount));
kfree(conn);
}
int ptlrpc_connection_init(void)
{
return rhashtable_init(&conn_hash, &conn_hash_params);
}
void ptlrpc_connection_fini(void)
{
rhashtable_free_and_destroy(&conn_hash, conn_exit, NULL);
}
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