SUNRPC: Add a transmission queue for RPC requests

Add the queue that will enforce the ordering of RPC task transmission.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

1 files changed, 75 insertions, 9 deletions

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index d527dc08540e..1f69d9f219af 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1058,6 +1058,72 @@ void xprt_request_wait_receive(struct rpc_task *task)
 	spin_unlock(&xprt->queue_lock);
 }
 
+static bool
+xprt_request_need_transmit(struct rpc_task *task)
+{
+	return !(task->tk_flags & RPC_TASK_NO_RETRANS_TIMEOUT) ||
+		xprt_request_retransmit_after_disconnect(task);
+}
+
+static bool
+xprt_request_need_enqueue_transmit(struct rpc_task *task, struct rpc_rqst *req)
+{
+	return xprt_request_need_transmit(task) &&
+		!test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate);
+}
+
+/**
+ * xprt_request_enqueue_transmit - queue a task for transmission
+ * @task: pointer to rpc_task
+ *
+ * Add a task to the transmission queue.
+ */
+void
+xprt_request_enqueue_transmit(struct rpc_task *task)
+{
+	struct rpc_rqst *req = task->tk_rqstp;
+	struct rpc_xprt *xprt = req->rq_xprt;
+
+	if (xprt_request_need_enqueue_transmit(task, req)) {
+		spin_lock(&xprt->queue_lock);
+		list_add_tail(&req->rq_xmit, &xprt->xmit_queue);
+		set_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate);
+		spin_unlock(&xprt->queue_lock);
+	}
+}
+
+/**
+ * xprt_request_dequeue_transmit_locked - remove a task from the transmission queue
+ * @task: pointer to rpc_task
+ *
+ * Remove a task from the transmission queue
+ * Caller must hold xprt->queue_lock
+ */
+static void
+xprt_request_dequeue_transmit_locked(struct rpc_task *task)
+{
+	xprt_task_clear_bytes_sent(task);
+	if (test_and_clear_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate))
+		list_del(&task->tk_rqstp->rq_xmit);
+}
+
+/**
+ * xprt_request_dequeue_transmit - remove a task from the transmission queue
+ * @task: pointer to rpc_task
+ *
+ * Remove a task from the transmission queue
+ */
+static void
+xprt_request_dequeue_transmit(struct rpc_task *task)
+{
+	struct rpc_rqst *req = task->tk_rqstp;
+	struct rpc_xprt *xprt = req->rq_xprt;
+
+	spin_lock(&xprt->queue_lock);
+	xprt_request_dequeue_transmit_locked(task);
+	spin_unlock(&xprt->queue_lock);
+}
+
 /**
  * xprt_prepare_transmit - reserve the transport before sending a request
  * @task: RPC task about to send a request
@@ -1077,12 +1143,8 @@ bool xprt_prepare_transmit(struct rpc_task *task)
 			task->tk_status = req->rq_reply_bytes_recvd;
 			goto out_unlock;
 		}
-		if ((task->tk_flags & RPC_TASK_NO_RETRANS_TIMEOUT) &&
-		    !xprt_request_retransmit_after_disconnect(task)) {
-			xprt->ops->set_retrans_timeout(task);
-			rpc_sleep_on(&xprt->pending, task, xprt_timer);
+		if (!test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate))
 			goto out_unlock;
-		}
 	}
 	if (!xprt->ops->reserve_xprt(xprt, task)) {
 		task->tk_status = -EAGAIN;
@@ -1116,11 +1178,11 @@ void xprt_transmit(struct rpc_task *task)
 
 	if (!req->rq_bytes_sent) {
 		if (xprt_request_data_received(task))
-			return;
+			goto out_dequeue;
 		/* Verify that our message lies in the RPCSEC_GSS window */
 		if (rpcauth_xmit_need_reencode(task)) {
 			task->tk_status = -EBADMSG;
-			return;
+			goto out_dequeue;
 		}
 	}
 
@@ -1135,7 +1197,6 @@ void xprt_transmit(struct rpc_task *task)
 	xprt_inject_disconnect(xprt);
 
 	dprintk("RPC: %5u xmit complete\n", task->tk_pid);
-	clear_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate);
 	task->tk_flags |= RPC_TASK_SENT;
 	spin_lock_bh(&xprt->transport_lock);
 
@@ -1147,6 +1208,8 @@ void xprt_transmit(struct rpc_task *task)
 	spin_unlock_bh(&xprt->transport_lock);
 
 	req->rq_connect_cookie = connect_cookie;
+out_dequeue:
+	xprt_request_dequeue_transmit(task);
 }
 
 static void xprt_add_backlog(struct rpc_xprt *xprt, struct rpc_task *task)
@@ -1420,9 +1483,11 @@ xprt_request_dequeue_all(struct rpc_task *task, struct rpc_rqst *req)
 {
 	struct rpc_xprt *xprt = req->rq_xprt;
 
-	if (test_bit(RPC_TASK_NEED_RECV, &task->tk_runstate) ||
+	if (test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate) ||
+	    test_bit(RPC_TASK_NEED_RECV, &task->tk_runstate) ||
 	    xprt_is_pinned_rqst(req)) {
 		spin_lock(&xprt->queue_lock);
+		xprt_request_dequeue_transmit_locked(task);
 		xprt_request_dequeue_receive_locked(task);
 		while (xprt_is_pinned_rqst(req)) {
 			set_bit(RPC_TASK_MSG_PIN_WAIT, &task->tk_runstate);
@@ -1493,6 +1558,7 @@ static void xprt_init(struct rpc_xprt *xprt, struct net *net)
 
 	INIT_LIST_HEAD(&xprt->free);
 	INIT_LIST_HEAD(&xprt->recv_queue);
+	INIT_LIST_HEAD(&xprt->xmit_queue);
 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 	spin_lock_init(&xprt->bc_pa_lock);
 	INIT_LIST_HEAD(&xprt->bc_pa_list);