Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 914edb1b authored by Stanislav Kinsbursky's avatar Stanislav Kinsbursky Committed by Trond Myklebust
Browse files

SUNRPC: introduce helpers for reference counted rpcbind clients 



v6:
1) added write memory barrier to rpcb_set_local to make sure, that rpcbind
clients become valid before rpcb_users assignment
2) explicitly set rpcb_users to 1 instead of incrementing it (looks clearer from
my pow).

v5: fixed races with rpcb_users in rpcb_get_local()

This helpers will be used for dynamical creation and destruction of rpcbind
clients.
Variable rpcb_users is actually a counter of lauched RPC services. If rpcbind
clients has been created already, then we just increase rpcb_users.

Signed-off-by: default avatarStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent dc6f55e9

net/sunrpc/rpcb_clnt.c

+53 −0
Original line number Diff line number Diff line
@@ -114,6 +114,9 @@ static struct rpc_program rpcb_program; 
static struct rpc_clnt *	rpcb_local_clnt;

static struct rpc_clnt *	rpcb_local_clnt4;



DEFINE_SPINLOCK(rpcb_clnt_lock);

unsigned int			rpcb_users;



struct rpcbind_args {

	struct rpc_xprt *	r_xprt;
@@ -161,6 +164,56 @@ static void rpcb_map_release(void *data) 
	kfree(map);

}



static int rpcb_get_local(void)

{

	int cnt;



	spin_lock(&rpcb_clnt_lock);

	if (rpcb_users)

		rpcb_users++;

	cnt = rpcb_users;

	spin_unlock(&rpcb_clnt_lock);



	return cnt;

}



void rpcb_put_local(void)

{

	struct rpc_clnt *clnt = rpcb_local_clnt;

	struct rpc_clnt *clnt4 = rpcb_local_clnt4;

	int shutdown;



	spin_lock(&rpcb_clnt_lock);

	if (--rpcb_users == 0) {

		rpcb_local_clnt = NULL;

		rpcb_local_clnt4 = NULL;

	}

	shutdown = !rpcb_users;

	spin_unlock(&rpcb_clnt_lock);



	if (shutdown) {

		/*

		 * cleanup_rpcb_clnt - remove xprtsock's sysctls, unregister

		 */

		if (clnt4)

			rpc_shutdown_client(clnt4);

		if (clnt)

			rpc_shutdown_client(clnt);

	}

}



static void rpcb_set_local(struct rpc_clnt *clnt, struct rpc_clnt *clnt4)

{

	/* Protected by rpcb_create_local_mutex */

	rpcb_local_clnt = clnt;

	rpcb_local_clnt4 = clnt4;

	smp_wmb(); 

	rpcb_users = 1;

	dprintk("RPC:       created new rpcb local clients (rpcb_local_clnt: "

			"%p, rpcb_local_clnt4: %p)\n", rpcb_local_clnt,

			rpcb_local_clnt4);

}



/*

 * Returns zero on success, otherwise a negative errno value

 * is returned.