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>
This commit is contained in:
\"Talpey, Thomas\ 2007-09-10 13:46:00 -04:00 committed by Trond Myklebust
parent 1244480976
commit 81c098af3d
2 changed files with 86 additions and 0 deletions

View File

@ -208,6 +208,15 @@ struct rpc_xprtsock_create {
struct rpc_timeout * timeout; /* optional timeout parameters */
};
struct xprt_class {
struct list_head list;
unsigned short family;
int protocol;
struct rpc_xprt * (*setup)(struct rpc_xprtsock_create *);
struct module *owner;
char name[32];
};
/*
* Transport operations used by ULPs
*/
@ -239,6 +248,8 @@ static inline __be32 *xprt_skip_transport_header(struct rpc_xprt *xprt, __be32 *
/*
* 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);

View File

@ -62,6 +62,9 @@ static inline void do_xprt_reserve(struct rpc_task *);
static void xprt_connect_status(struct rpc_task *task);
static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
static spinlock_t xprt_list_lock = SPIN_LOCK_UNLOCKED;
static LIST_HEAD(xprt_list);
/*
* The transport code maintains an estimate on the maximum number of out-
* standing RPC requests, using a smoothed version of the congestion
@ -80,6 +83,78 @@ static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
#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