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33 #define DEBUG_SUBSYSTEM S_RPC
34 #include <obd_support.h>
35 #include <obd_class.h>
36 #include <lustre_net.h>
38 #include "ptlrpc_internal.h"
40 static struct rhashtable conn_hash;
43 * struct lnet_process_id may contain unassigned bytes which might not
44 * be zero, so we cannot just hash and compare bytes.
47 static u32 lnet_process_id_hash(const void *data, u32 len, u32 seed)
49 const struct lnet_process_id *lpi = data;
51 seed = hash_32(seed ^ lpi->pid, 32);
52 seed ^= hash_64(lpi->nid, 32);
56 static int lnet_process_id_cmp(struct rhashtable_compare_arg *arg,
59 const struct lnet_process_id *lpi = arg->key;
60 const struct ptlrpc_connection *con = obj;
62 if (lpi->nid == con->c_peer.nid &&
63 lpi->pid == con->c_peer.pid)
68 static const struct rhashtable_params conn_hash_params = {
69 .key_len = 1, /* actually variable-length */
70 .key_offset = offsetof(struct ptlrpc_connection, c_peer),
71 .head_offset = offsetof(struct ptlrpc_connection, c_hash),
72 .hashfn = lnet_process_id_hash,
73 .obj_cmpfn = lnet_process_id_cmp,
76 struct ptlrpc_connection *
77 ptlrpc_connection_get(struct lnet_process_id peer, lnet_nid_t self,
78 struct obd_uuid *uuid)
80 struct ptlrpc_connection *conn, *conn2;
83 peer.nid = LNetPrimaryNID(peer.nid);
84 conn = rhashtable_lookup_fast(&conn_hash, &peer, conn_hash_params);
86 ptlrpc_connection_addref(conn);
96 atomic_set(&conn->c_refcount, 1);
98 obd_str2uuid(&conn->c_remote_uuid, uuid->uuid);
101 * Add the newly created conn to the hash, on key collision we
102 * lost a racing addition and must destroy our newly allocated
103 * connection. The object which exists in the hash will be
104 * returned,otherwise NULL is returned on success.
106 conn2 = rhashtable_lookup_get_insert_fast(&conn_hash, &conn->c_hash,
109 /* insertion failed */
114 ptlrpc_connection_addref(conn);
118 CDEBUG(D_INFO, "conn=%p refcount %d to %s\n",
119 conn, atomic_read(&conn->c_refcount),
120 libcfs_nid2str(conn->c_peer.nid));
124 int ptlrpc_connection_put(struct ptlrpc_connection *conn)
132 LASSERT(atomic_read(&conn->c_refcount) > 0);
135 * We do not remove connection from hashtable and
136 * do not free it even if last caller released ref,
137 * as we want to have it cached for the case it is
140 * Deallocating it and later creating new connection
141 * again would be wastful. This way we also avoid
142 * expensive locking to protect things from get/put
143 * race when found cached connection is freed by
144 * ptlrpc_connection_put().
146 * It will be freed later in module unload time,
147 * when ptlrpc_connection_fini()->lh_exit->conn_exit()
150 if (atomic_dec_return(&conn->c_refcount) == 0)
153 CDEBUG(D_INFO, "PUT conn=%p refcount %d to %s\n",
154 conn, atomic_read(&conn->c_refcount),
155 libcfs_nid2str(conn->c_peer.nid));
160 struct ptlrpc_connection *
161 ptlrpc_connection_addref(struct ptlrpc_connection *conn)
165 atomic_inc(&conn->c_refcount);
166 CDEBUG(D_INFO, "conn=%p refcount %d to %s\n",
167 conn, atomic_read(&conn->c_refcount),
168 libcfs_nid2str(conn->c_peer.nid));
174 conn_exit(void *vconn, void *data)
176 struct ptlrpc_connection *conn = vconn;
179 * Nothing should be left. Connection user put it and
180 * connection also was deleted from table by this time
181 * so we should have 0 refs.
183 LASSERTF(atomic_read(&conn->c_refcount) == 0,
184 "Busy connection with %d refs\n",
185 atomic_read(&conn->c_refcount));
189 int ptlrpc_connection_init(void)
191 return rhashtable_init(&conn_hash, &conn_hash_params);
194 void ptlrpc_connection_fini(void)
196 rhashtable_free_and_destroy(&conn_hash, conn_exit, NULL);