SUNRPC: Don't wake tasks during connection abort

When aborting a connection to preserve source ports, don't wake the task in
xs_error_report.  This allows tasks with RPC_TASK_SOFTCONN to succeed if the
connection needs to be re-established since it preserves the task's status
instead of setting it to the status of the aborting kernel_connect().

This may also avoid a potential conflict on the socket's lock.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Cc: stable@vger.kernel.org # 3.14+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

include/linux/sunrpc/xprt.h

@@ -357,6 +357,7 @@ int			xs_swapper(struct rpc_xprt *xprt, int enable);
 #define XPRT_CONNECTION_ABORT	(7)
 #define XPRT_CONNECTION_CLOSE	(8)
 #define XPRT_CONGESTED		(9)
+#define XPRT_CONNECTION_REUSE	(10)
 
 static inline void xprt_set_connected(struct rpc_xprt *xprt)
 {

net/sunrpc/xprtsock.c

@@ -845,6 +845,8 @@ static void xs_error_report(struct sock *sk)
 	dprintk("RPC:       xs_error_report client %p, error=%d...\n",
 			xprt, -err);
 	trace_rpc_socket_error(xprt, sk->sk_socket, err);
+	if (test_bit(XPRT_CONNECTION_REUSE, &xprt->state))
+		goto out;
 	xprt_wake_pending_tasks(xprt, err);
  out:
 	read_unlock_bh(&sk->sk_callback_lock);
@@ -2261,7 +2263,9 @@ static void xs_tcp_setup_socket(struct work_struct *work)
 		abort_and_exit = test_and_clear_bit(XPRT_CONNECTION_ABORT,
 				&xprt->state);
 		/* "close" the socket, preserving the local port */
+		set_bit(XPRT_CONNECTION_REUSE, &xprt->state);
 		xs_tcp_reuse_connection(transport);
+		clear_bit(XPRT_CONNECTION_REUSE, &xprt->state);
 
 		if (abort_and_exit)
 			goto out_eagain;