1 files changed, 248 insertions, 0 deletions
diff --git a/drivers/staging/lustre/lustre/ptlrpc/connection.c b/drivers/staging/lustre/lustre/ptlrpc/connection.c
new file mode 100644
index 000000000000..a0757f372be5
--- /dev/null
+++ b/drivers/staging/lustre/lustre/ptlrpc/connection.c
@@ -0,0 +1,248 @@
+/*
+ * 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.sun.com/software/products/lustre/docs/GPLv2.pdf
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ * 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 cfs_hash_t *conn_hash = NULL;
+static cfs_hash_ops_t conn_hash_ops;
+
+struct ptlrpc_connection *
+ptlrpc_connection_get(lnet_process_id_t peer, lnet_nid_t self,
+		      struct obd_uuid *uuid)
+{
+	struct ptlrpc_connection *conn, *conn2;
+	ENTRY;
+
+	conn = cfs_hash_lookup(conn_hash, &peer);
+	if (conn)
+		GOTO(out, conn);
+
+	OBD_ALLOC_PTR(conn);
+	if (!conn)
+		RETURN(NULL);
+
+	conn->c_peer = peer;
+	conn->c_self = self;
+	INIT_HLIST_NODE(&conn->c_hash);
+	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 has will be
+	 * returned and may be compared against out object.
+	 */
+	/* In the function below, .hs_keycmp resolves to
+	 * conn_keycmp() */
+	/* coverity[overrun-buffer-val] */
+	conn2 = cfs_hash_findadd_unique(conn_hash, &peer, &conn->c_hash);
+	if (conn != conn2) {
+		OBD_FREE_PTR(conn);
+		conn = conn2;
+	}
+	EXIT;
+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;
+}
+EXPORT_SYMBOL(ptlrpc_connection_get);
+
+int ptlrpc_connection_put(struct ptlrpc_connection *conn)
+{
+	int rc = 0;
+	ENTRY;
+
+	if (!conn)
+		RETURN(rc);
+
+	LASSERT(atomic_read(&conn->c_refcount) > 1);
+
+	/*
+	 * 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) == 1)
+		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);
+}
+EXPORT_SYMBOL(ptlrpc_connection_put);
+
+struct ptlrpc_connection *
+ptlrpc_connection_addref(struct ptlrpc_connection *conn)
+{
+	ENTRY;
+
+	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);
+}
+EXPORT_SYMBOL(ptlrpc_connection_addref);
+
+int ptlrpc_connection_init(void)
+{
+	ENTRY;
+
+	conn_hash = cfs_hash_create("CONN_HASH",
+				    HASH_CONN_CUR_BITS,
+				    HASH_CONN_MAX_BITS,
+				    HASH_CONN_BKT_BITS, 0,
+				    CFS_HASH_MIN_THETA,
+				    CFS_HASH_MAX_THETA,
+				    &conn_hash_ops, CFS_HASH_DEFAULT);
+	if (!conn_hash)
+		RETURN(-ENOMEM);
+
+	RETURN(0);
+}
+EXPORT_SYMBOL(ptlrpc_connection_init);
+
+void ptlrpc_connection_fini(void) {
+	ENTRY;
+	cfs_hash_putref(conn_hash);
+	EXIT;
+}
+EXPORT_SYMBOL(ptlrpc_connection_fini);
+
+/*
+ * Hash operations for net_peer<->connection
+ */
+static unsigned
+conn_hashfn(cfs_hash_t *hs, const void *key, unsigned mask)
+{
+	return cfs_hash_djb2_hash(key, sizeof(lnet_process_id_t), mask);
+}
+
+static int
+conn_keycmp(const void *key, struct hlist_node *hnode)
+{
+	struct ptlrpc_connection *conn;
+	const lnet_process_id_t *conn_key;
+
+	LASSERT(key != NULL);
+	conn_key = (lnet_process_id_t*)key;
+	conn = hlist_entry(hnode, struct ptlrpc_connection, c_hash);
+
+	return conn_key->nid == conn->c_peer.nid &&
+	       conn_key->pid == conn->c_peer.pid;
+}
+
+static void *
+conn_key(struct hlist_node *hnode)
+{
+	struct ptlrpc_connection *conn;
+	conn = hlist_entry(hnode, struct ptlrpc_connection, c_hash);
+	return &conn->c_peer;
+}
+
+static void *
+conn_object(struct hlist_node *hnode)
+{
+	return hlist_entry(hnode, struct ptlrpc_connection, c_hash);
+}
+
+static void
+conn_get(cfs_hash_t *hs, struct hlist_node *hnode)
+{
+	struct ptlrpc_connection *conn;
+
+	conn = hlist_entry(hnode, struct ptlrpc_connection, c_hash);
+	atomic_inc(&conn->c_refcount);
+}
+
+static void
+conn_put_locked(cfs_hash_t *hs, struct hlist_node *hnode)
+{
+	struct ptlrpc_connection *conn;
+
+	conn = hlist_entry(hnode, struct ptlrpc_connection, c_hash);
+	atomic_dec(&conn->c_refcount);
+}
+
+static void
+conn_exit(cfs_hash_t *hs, struct hlist_node *hnode)
+{
+	struct ptlrpc_connection *conn;
+
+	conn = hlist_entry(hnode, struct ptlrpc_connection, c_hash);
+	/*
+	 * 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));
+	OBD_FREE_PTR(conn);
+}
+
+static cfs_hash_ops_t conn_hash_ops = {
+	.hs_hash	= conn_hashfn,
+	.hs_keycmp      = conn_keycmp,
+	.hs_key	 = conn_key,
+	.hs_object      = conn_object,
+	.hs_get	 = conn_get,
+	.hs_put_locked  = conn_put_locked,
+	.hs_exit	= conn_exit,
+};