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Commit 81c098af authored by \"Talpey, Thomas\'s avatar \"Talpey, Thomas\ Committed by Trond Myklebust
Browse files

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: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTom Talpey <tmt@netapp.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 12444809

include/linux/sunrpc/xprt.h

+11 −0
Original line number Diff line number Diff line
@@ -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);

net/sunrpc/xprt.c

+75 −0
Original line number Diff line number Diff line
@@ -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