[PATCH] RPC: separate TCP and UDP write space callbacks

 Split the socket write space callback function into a TCP version and UDP
 version, eliminating one dependence on the "xprt->stream" variable.

 Keep the common pieces of this path in xprt.c so other transports can use
 it too.

 Test-plan:
 Write-intensive workload on a single mount point.

 Version: Thu, 11 Aug 2005 16:07:51 -0400

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 247fa1e..31ef7dc 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -241,6 +241,40 @@ void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status)
 		rpc_wake_up(&xprt->pending);
 }
 
+/**
+ * xprt_wait_for_buffer_space - wait for transport output buffer to clear
+ * @task: task to be put to sleep
+ *
+ */
+void xprt_wait_for_buffer_space(struct rpc_task *task)
+{
+	struct rpc_rqst *req = task->tk_rqstp;
+	struct rpc_xprt *xprt = req->rq_xprt;
+
+	task->tk_timeout = req->rq_timeout;
+	rpc_sleep_on(&xprt->pending, task, NULL, NULL);
+}
+
+/**
+ * xprt_write_space - wake the task waiting for transport output buffer space
+ * @xprt: transport with waiting tasks
+ *
+ * Can be called in a soft IRQ context, so xprt_write_space never sleeps.
+ */
+void xprt_write_space(struct rpc_xprt *xprt)
+{
+	if (unlikely(xprt->shutdown))
+		return;
+
+	spin_lock_bh(&xprt->transport_lock);
+	if (xprt->snd_task) {
+		dprintk("RPC:      write space: waking waiting task on xprt %p\n",
+				xprt);
+		rpc_wake_up_task(xprt->snd_task);
+	}
+	spin_unlock_bh(&xprt->transport_lock);
+}
+
 static void xprt_reset_majortimeo(struct rpc_rqst *req)
 {
 	struct rpc_timeout *to = &req->rq_xprt->timeout;