SUNRPC: Make RPC portmapper use per-transport storage

Move connection and bind state that was maintained in the rpc_clnt
structure to the rpc_xprt structure.  This will allow the creation of
a clean API for plugging in different types of bind mechanisms.

This brings improvements such as the elimination of a single spin lock to
control serialization for all in-kernel RPC binding.  A set of per-xprt
bitops is used to serialize tasks during RPC binding, just like it now
works for making RPC transport connections.

Test-plan:
Destructive testing (unplugging the network temporarily).  Connectathon
with UDP and TCP.  NFSv2/3 and NFSv4 mounting should be carefully checked.
Probably need to rig a server where certain services aren't running, or
that returns an error for some typical operation.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index a71106723d71..4ce82616873d 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -138,6 +138,7 @@ struct rpc_xprt {
         unsigned int            tsh_size;       /* size of transport specific
                                                    header */
 
+        struct rpc_wait_queue   binding;        /* requests waiting on rpcbind */
         struct rpc_wait_queue   sending;        /* requests waiting to send */
         struct rpc_wait_queue   resend;         /* requests waiting to resend */
         struct rpc_wait_queue   pending;        /* requests in flight */
@@ -270,6 +271,7 @@ int			xs_setup_tcp(struct rpc_xprt *xprt, struct rpc_timeout *to);
 #define XPRT_CONNECTING         (2)
 #define XPRT_CLOSE_WAIT         (3)
 #define XPRT_BOUND              (4)
+#define XPRT_BINDING            (5)
 
 static inline void xprt_set_connected(struct rpc_xprt *xprt)
 {
@@ -328,6 +330,18 @@ static inline void xprt_clear_bound(struct rpc_xprt *xprt)
         clear_bit(XPRT_BOUND, &xprt->state);
 }
 
+static inline void xprt_clear_binding(struct rpc_xprt *xprt)
+{
+        smp_mb__before_clear_bit();
+        clear_bit(XPRT_BINDING, &xprt->state);
+        smp_mb__after_clear_bit();
+}
+
+static inline int xprt_test_and_set_binding(struct rpc_xprt *xprt)
+{
+        return test_and_set_bit(XPRT_BINDING, &xprt->state);
+}
+
 #endif /* __KERNEL__*/
 
 #endif /* _LINUX_SUNRPC_XPRT_H */