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author\"Talpey, Thomas\ <Thomas.Talpey@netapp.com>2007-09-10 13:46:00 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2007-10-09 17:17:40 -0400
commit81c098af3da7981902e9f8163aeccc2467c4ba6d (patch)
treeb98e3c8c9e519e34abf721410de70373cedb4a9f /net/sunrpc/xprt.c
parent1244480976d357447aeddd3f44977586bfa0462b (diff)
SUNRPC: Provide a new API for registering transport implementations
To allow transport capabilities to be loaded dynamically, provide an API for registering and unregistering the transports with the RPC client. Eventually xprt_create_transport() will be changed to search the list of registered transports when initializing a fresh transport. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Tom Talpey <tmt@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'net/sunrpc/xprt.c')
-rw-r--r--net/sunrpc/xprt.c75
1 files changed, 75 insertions, 0 deletions
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index bc13616e7fdc..520859622af5 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -62,6 +62,9 @@ static inline void do_xprt_reserve(struct rpc_task *);
62static void xprt_connect_status(struct rpc_task *task); 62static void xprt_connect_status(struct rpc_task *task);
63static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *); 63static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
64 64
65static spinlock_t xprt_list_lock = SPIN_LOCK_UNLOCKED;
66static LIST_HEAD(xprt_list);
67
65/* 68/*
66 * The transport code maintains an estimate on the maximum number of out- 69 * The transport code maintains an estimate on the maximum number of out-
67 * standing RPC requests, using a smoothed version of the congestion 70 * standing RPC requests, using a smoothed version of the congestion
@@ -81,6 +84,78 @@ static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
81#define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd) 84#define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)
82 85
83/** 86/**
87 * xprt_register_transport - register a transport implementation
88 * @transport: transport to register
89 *
90 * If a transport implementation is loaded as a kernel module, it can
91 * call this interface to make itself known to the RPC client.
92 *
93 * Returns:
94 * 0: transport successfully registered
95 * -EEXIST: transport already registered
96 * -EINVAL: transport module being unloaded
97 */
98int xprt_register_transport(struct xprt_class *transport)
99{
100 struct xprt_class *t;
101 int result;
102
103 result = -EEXIST;
104 spin_lock(&xprt_list_lock);
105 list_for_each_entry(t, &xprt_list, list) {
106 /* don't register the same transport class twice */
107 if (t == transport)
108 goto out;
109 }
110
111 result = -EINVAL;
112 if (try_module_get(THIS_MODULE)) {
113 list_add_tail(&transport->list, &xprt_list);
114 printk(KERN_INFO "RPC: Registered %s transport module.\n",
115 transport->name);
116 result = 0;
117 }
118
119out:
120 spin_unlock(&xprt_list_lock);
121 return result;
122}
123EXPORT_SYMBOL_GPL(xprt_register_transport);
124
125/**
126 * xprt_unregister_transport - unregister a transport implementation
127 * transport: transport to unregister
128 *
129 * Returns:
130 * 0: transport successfully unregistered
131 * -ENOENT: transport never registered
132 */
133int xprt_unregister_transport(struct xprt_class *transport)
134{
135 struct xprt_class *t;
136 int result;
137
138 result = 0;
139 spin_lock(&xprt_list_lock);
140 list_for_each_entry(t, &xprt_list, list) {
141 if (t == transport) {
142 printk(KERN_INFO
143 "RPC: Unregistered %s transport module.\n",
144 transport->name);
145 list_del_init(&transport->list);
146 module_put(THIS_MODULE);
147 goto out;
148 }
149 }
150 result = -ENOENT;
151
152out:
153 spin_unlock(&xprt_list_lock);
154 return result;
155}
156EXPORT_SYMBOL_GPL(xprt_unregister_transport);
157
158/**
84 * xprt_reserve_xprt - serialize write access to transports 159 * xprt_reserve_xprt - serialize write access to transports
85 * @task: task that is requesting access to the transport 160 * @task: task that is requesting access to the transport
86 * 161 *