1 /*
2 * GPL HEADER START
3 *
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 only,
8 * as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License
17 * version 2 along with this program; If not, see
18 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
19 *
20 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
21 * CA 95054 USA or visit www.sun.com if you need additional information or
22 * have any questions.
23 *
24 * GPL HEADER END
25 */
26 /*
27 * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
28 * Use is subject to license terms.
29 *
30 * Copyright (c) 2011, Intel Corporation.
31 */
32 /*
33 * This file is part of Lustre, http://www.lustre.org/
34 * Lustre is a trademark of Sun Microsystems, Inc.
35 */
36
37 #define DEBUG_SUBSYSTEM S_RPC
38 #include "../include/obd_support.h"
39 #include "../include/obd_class.h"
40 #include "../include/lustre_net.h"
41
42 #include "ptlrpc_internal.h"
43
44 static struct cfs_hash *conn_hash;
45 static struct cfs_hash_ops conn_hash_ops;
46
47 struct ptlrpc_connection *
ptlrpc_connection_get(lnet_process_id_t peer,lnet_nid_t self,struct obd_uuid * uuid)48 ptlrpc_connection_get(lnet_process_id_t peer, lnet_nid_t self,
49 struct obd_uuid *uuid)
50 {
51 struct ptlrpc_connection *conn, *conn2;
52
53 conn = cfs_hash_lookup(conn_hash, &peer);
54 if (conn)
55 goto out;
56
57 conn = kzalloc(sizeof(*conn), GFP_NOFS);
58 if (!conn)
59 return NULL;
60
61 conn->c_peer = peer;
62 conn->c_self = self;
63 INIT_HLIST_NODE(&conn->c_hash);
64 atomic_set(&conn->c_refcount, 1);
65 if (uuid)
66 obd_str2uuid(&conn->c_remote_uuid, uuid->uuid);
67
68 /*
69 * Add the newly created conn to the hash, on key collision we
70 * lost a racing addition and must destroy our newly allocated
71 * connection. The object which exists in the has will be
72 * returned and may be compared against out object.
73 */
74 /* In the function below, .hs_keycmp resolves to
75 * conn_keycmp() */
76 /* coverity[overrun-buffer-val] */
77 conn2 = cfs_hash_findadd_unique(conn_hash, &peer, &conn->c_hash);
78 if (conn != conn2) {
79 kfree(conn);
80 conn = conn2;
81 }
82 out:
83 CDEBUG(D_INFO, "conn=%p refcount %d to %s\n",
84 conn, atomic_read(&conn->c_refcount),
85 libcfs_nid2str(conn->c_peer.nid));
86 return conn;
87 }
88 EXPORT_SYMBOL(ptlrpc_connection_get);
89
ptlrpc_connection_put(struct ptlrpc_connection * conn)90 int ptlrpc_connection_put(struct ptlrpc_connection *conn)
91 {
92 int rc = 0;
93
94 if (!conn)
95 return rc;
96
97 LASSERT(atomic_read(&conn->c_refcount) > 1);
98
99 /*
100 * We do not remove connection from hashtable and
101 * do not free it even if last caller released ref,
102 * as we want to have it cached for the case it is
103 * needed again.
104 *
105 * Deallocating it and later creating new connection
106 * again would be wastful. This way we also avoid
107 * expensive locking to protect things from get/put
108 * race when found cached connection is freed by
109 * ptlrpc_connection_put().
110 *
111 * It will be freed later in module unload time,
112 * when ptlrpc_connection_fini()->lh_exit->conn_exit()
113 * path is called.
114 */
115 if (atomic_dec_return(&conn->c_refcount) == 1)
116 rc = 1;
117
118 CDEBUG(D_INFO, "PUT conn=%p refcount %d to %s\n",
119 conn, atomic_read(&conn->c_refcount),
120 libcfs_nid2str(conn->c_peer.nid));
121
122 return rc;
123 }
124 EXPORT_SYMBOL(ptlrpc_connection_put);
125
126 struct ptlrpc_connection *
ptlrpc_connection_addref(struct ptlrpc_connection * conn)127 ptlrpc_connection_addref(struct ptlrpc_connection *conn)
128 {
129 atomic_inc(&conn->c_refcount);
130 CDEBUG(D_INFO, "conn=%p refcount %d to %s\n",
131 conn, atomic_read(&conn->c_refcount),
132 libcfs_nid2str(conn->c_peer.nid));
133
134 return conn;
135 }
136 EXPORT_SYMBOL(ptlrpc_connection_addref);
137
ptlrpc_connection_init(void)138 int ptlrpc_connection_init(void)
139 {
140 conn_hash = cfs_hash_create("CONN_HASH",
141 HASH_CONN_CUR_BITS,
142 HASH_CONN_MAX_BITS,
143 HASH_CONN_BKT_BITS, 0,
144 CFS_HASH_MIN_THETA,
145 CFS_HASH_MAX_THETA,
146 &conn_hash_ops, CFS_HASH_DEFAULT);
147 if (!conn_hash)
148 return -ENOMEM;
149
150 return 0;
151 }
152 EXPORT_SYMBOL(ptlrpc_connection_init);
153
ptlrpc_connection_fini(void)154 void ptlrpc_connection_fini(void)
155 {
156 cfs_hash_putref(conn_hash);
157 }
158 EXPORT_SYMBOL(ptlrpc_connection_fini);
159
160 /*
161 * Hash operations for net_peer<->connection
162 */
163 static unsigned
conn_hashfn(struct cfs_hash * hs,const void * key,unsigned mask)164 conn_hashfn(struct cfs_hash *hs, const void *key, unsigned mask)
165 {
166 return cfs_hash_djb2_hash(key, sizeof(lnet_process_id_t), mask);
167 }
168
169 static int
conn_keycmp(const void * key,struct hlist_node * hnode)170 conn_keycmp(const void *key, struct hlist_node *hnode)
171 {
172 struct ptlrpc_connection *conn;
173 const lnet_process_id_t *conn_key;
174
175 LASSERT(key != NULL);
176 conn_key = key;
177 conn = hlist_entry(hnode, struct ptlrpc_connection, c_hash);
178
179 return conn_key->nid == conn->c_peer.nid &&
180 conn_key->pid == conn->c_peer.pid;
181 }
182
183 static void *
conn_key(struct hlist_node * hnode)184 conn_key(struct hlist_node *hnode)
185 {
186 struct ptlrpc_connection *conn;
187
188 conn = hlist_entry(hnode, struct ptlrpc_connection, c_hash);
189 return &conn->c_peer;
190 }
191
192 static void *
conn_object(struct hlist_node * hnode)193 conn_object(struct hlist_node *hnode)
194 {
195 return hlist_entry(hnode, struct ptlrpc_connection, c_hash);
196 }
197
198 static void
conn_get(struct cfs_hash * hs,struct hlist_node * hnode)199 conn_get(struct cfs_hash *hs, struct hlist_node *hnode)
200 {
201 struct ptlrpc_connection *conn;
202
203 conn = hlist_entry(hnode, struct ptlrpc_connection, c_hash);
204 atomic_inc(&conn->c_refcount);
205 }
206
207 static void
conn_put_locked(struct cfs_hash * hs,struct hlist_node * hnode)208 conn_put_locked(struct cfs_hash *hs, struct hlist_node *hnode)
209 {
210 struct ptlrpc_connection *conn;
211
212 conn = hlist_entry(hnode, struct ptlrpc_connection, c_hash);
213 atomic_dec(&conn->c_refcount);
214 }
215
216 static void
conn_exit(struct cfs_hash * hs,struct hlist_node * hnode)217 conn_exit(struct cfs_hash *hs, struct hlist_node *hnode)
218 {
219 struct ptlrpc_connection *conn;
220
221 conn = hlist_entry(hnode, struct ptlrpc_connection, c_hash);
222 /*
223 * Nothing should be left. Connection user put it and
224 * connection also was deleted from table by this time
225 * so we should have 0 refs.
226 */
227 LASSERTF(atomic_read(&conn->c_refcount) == 0,
228 "Busy connection with %d refs\n",
229 atomic_read(&conn->c_refcount));
230 kfree(conn);
231 }
232
233 static struct cfs_hash_ops conn_hash_ops = {
234 .hs_hash = conn_hashfn,
235 .hs_keycmp = conn_keycmp,
236 .hs_key = conn_key,
237 .hs_object = conn_object,
238 .hs_get = conn_get,
239 .hs_put_locked = conn_put_locked,
240 .hs_exit = conn_exit,
241 };
242