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 <[email protected]>
---
include/linux/sunrpc/xprt.h | 11 +++++++
net/sunrpc/xprt.c | 71 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 82 insertions(+), 0 deletions(-)
Index: linux-2.6.22/include/linux/sunrpc/xprt.h
===================================================================
--- linux-2.6.22.orig/include/linux/sunrpc/xprt.h
+++ linux-2.6.22/include/linux/sunrpc/xprt.h
@@ -124,6 +124,15 @@ struct rpc_xprt_ops {
void (*print_stats)(struct rpc_xprt *xprt, struct seq_file *seq);
};
+struct xprt_class {
+ struct list_head list;
+ unsigned short family;
+ int protocol;
+ struct rpc_xprt * (*setup)(struct sockaddr *, size_t, struct rpc_timeout *);
+ struct module * owner;
+ char name[32];
+};
+
struct rpc_xprt {
struct kref kref; /* Reference count */
struct rpc_xprt_ops * ops; /* transport methods */
@@ -227,6 +236,8 @@ static inline __be32 *xprt_skip_transpor
/*
* Transport switch helper functions
*/
+int xprt_register_transport(struct xprt_class *type);
+int xprt_unregister_transport(struct xprt_class *type);
void xprt_set_retrans_timeout_def(struct rpc_task *task);
void xprt_set_retrans_timeout_rtt(struct rpc_task *task);
void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);
@@ -242,8 +253,6 @@ void xprt_disconnect(struct rpc_xprt *
/*
* Socket transport setup operations
*/
-struct rpc_xprt * xs_setup_udp(struct sockaddr *addr, size_t addrlen, struct rpc_timeout *to);
-struct rpc_xprt * xs_setup_tcp(struct sockaddr *addr, size_t addrlen, struct rpc_timeout *to);
int init_socket_xprt(void);
void cleanup_socket_xprt(void);
Index: linux-2.6.22/net/sunrpc/xprt.c
===================================================================
--- linux-2.6.22.orig/net/sunrpc/xprt.c
+++ linux-2.6.22/net/sunrpc/xprt.c
@@ -81,6 +81,77 @@ static int __xprt_get_cong(struct r
#define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)
/**
+ * xprt_register_transport - register a transport implementation
+ * @transport: transport to register
+ *
+ * If a transport implementation is loaded as a kernel module, it can
+ * call this interface to make itself known to the RPC client.
+ *
+ * Returns:
+ * 0: transport successfully registered
+ * -EEXIST: transport already registered
+ * -EINVAL: transport module being unloaded
+ */
+int xprt_register_transport(struct xprt_class *transport)
+{
+ struct xprt_class *t;
+ int result;
+
+ result = -EEXIST;
+ spin_lock(&xprt_list_lock);
+ list_for_each_entry(t, &xprt_list, list) {
+ /* don't register the same transport class twice */
+ if (t == transport)
+ goto out;
+ }
+
+ result = -EINVAL;
+ if (try_module_get(THIS_MODULE)) {
+ list_add_tail(&transport->list, &xprt_list);
+ printk(KERN_INFO "RPC: Registered %s transport module.\n",
+ transport->name);
+ result = 0;
+ }
+
+out:
+ spin_unlock(&xprt_list_lock);
+ return result;
+}
+EXPORT_SYMBOL_GPL(xprt_register_transport);
+
+/**
+ * xprt_unregister_transport - unregister a transport implementation
+ * transport: transport to unregister
+ *
+ * Returns:
+ * 0: transport successfully unregistered
+ * -ENOENT: transport never registered
+ */
+int xprt_unregister_transport(struct xprt_class *transport)
+{
+ struct xprt_class *t;
+ int result;
+
+ result = 0;
+ spin_lock(&xprt_list_lock);
+ list_for_each_entry(t, &xprt_list, list) {
+ if (t == transport) {
+ printk(KERN_INFO "RPC: Unregistered %s transport module.\n",
+ transport->name);
+ list_del_init(&transport->list);
+ module_put(THIS_MODULE);
+ goto out;
+ }
+ }
+ result = -ENOENT;
+
+out:
+ spin_unlock(&xprt_list_lock);
+ return result;
+}
+EXPORT_SYMBOL_GPL(xprt_unregister_transport);
+
+/**
* xprt_reserve_xprt - serialize write access to transports
* @task: task that is requesting access to the transport
*
-------------------------------------------------------------------------
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