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authorStanislav Kinsbursky <skinsbursky@parallels.com>2011-10-25 14:16:36 +0300
committerTrond Myklebust <Trond.Myklebust@netapp.com>2011-10-25 13:15:48 +0200
commit914edb1bb2abe2ae4775368f2ffb7f41010fb81e (patch)
treec3a46e520de7e003c1a867dae4aa3740c4f074d2 /net/sunrpc
parentdc6f55e9f8dac4b6479be67c5c9128ad37bb491f (diff)
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: Stanislav Kinsbursky <skinsbursky@parallels.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'net/sunrpc')
-rw-r--r--net/sunrpc/rpcb_clnt.c53
1 files changed, 53 insertions, 0 deletions
diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c
index f588b852d41..78af56579fa 100644
--- a/net/sunrpc/rpcb_clnt.c
+++ b/net/sunrpc/rpcb_clnt.c
@@ -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.