RPC/RDMA: harden connection logic against missing/late rdma_cm upcalls.

Add defensive timeouts to wait_for_completion() calls in RDMA
address resolution, and make them interruptible. Fix the timeout
units to milliseconds (formerly jiffies) and move to private header.

Signed-off-by: Tom Talpey <talpey@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

include/linux/sunrpc/xprtrdma.h

@@ -66,9 +66,6 @@
 
 #define RPCRDMA_INLINE_PAD_THRESH  (512)/* payload threshold to pad (bytes) */
 
-#define RDMA_RESOLVE_TIMEOUT	(5*HZ)	/* TBD 5 seconds */
-#define RDMA_CONNECT_RETRY_MAX	(2)	/* retries if no listener backlog */
-
 /* memory registration strategies */
 #define RPCRDMA_PERSISTENT_REGISTRATION (1)
 

net/sunrpc/xprtrdma/verbs.c

@@ -284,6 +284,7 @@ rpcrdma_conn_upcall(struct rdma_cm_id *id, struct rdma_cm_event *event)
 	switch (event->event) {
 	case RDMA_CM_EVENT_ADDR_RESOLVED:
 	case RDMA_CM_EVENT_ROUTE_RESOLVED:
+		ia->ri_async_rc = 0;
 		complete(&ia->ri_done);
 		break;
 	case RDMA_CM_EVENT_ADDR_ERROR:
@@ -363,26 +364,28 @@ rpcrdma_create_id(struct rpcrdma_xprt *xprt,
 		return id;
 	}
 
-	ia->ri_async_rc = 0;
+	ia->ri_async_rc = -ETIMEDOUT;
 	rc = rdma_resolve_addr(id, NULL, addr, RDMA_RESOLVE_TIMEOUT);
 	if (rc) {
 		dprintk("RPC:       %s: rdma_resolve_addr() failed %i\n",
 			__func__, rc);
 		goto out;
 	}
-	wait_for_completion(&ia->ri_done);
+	wait_for_completion_interruptible_timeout(&ia->ri_done,
+				msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT) + 1);
 	rc = ia->ri_async_rc;
 	if (rc)
 		goto out;
 
-	ia->ri_async_rc = 0;
+	ia->ri_async_rc = -ETIMEDOUT;
 	rc = rdma_resolve_route(id, RDMA_RESOLVE_TIMEOUT);
 	if (rc) {
 		dprintk("RPC:       %s: rdma_resolve_route() failed %i\n",
 			__func__, rc);
 		goto out;
 	}
-	wait_for_completion(&ia->ri_done);
+	wait_for_completion_interruptible_timeout(&ia->ri_done,
+				msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT) + 1);
 	rc = ia->ri_async_rc;
 	if (rc)
 		goto out;

net/sunrpc/xprtrdma/xprt_rdma.h

@@ -51,6 +51,9 @@
 #include <linux/sunrpc/rpc_rdma.h> 	/* RPC/RDMA protocol */
 #include <linux/sunrpc/xprtrdma.h> 	/* xprt parameters */
 
+#define RDMA_RESOLVE_TIMEOUT	(5000)	/* 5 seconds */
+#define RDMA_CONNECT_RETRY_MAX	(2)	/* retries if no listener backlog */
+
 /*
  * Interface Adapter -- one per transport instance
  */