xprtrdma: Put Send CQ in IB_POLL_WORKQUEUE mode

Lift the Send and LocalInv completion handlers out of soft IRQ mode
to make room for other work. Also, move the Send CQ to a different
CPU than the CPU where the Receive CQ is running, for improved
scalability.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net/sunrpc/xprtrdma/verbs.c

@@ -558,7 +558,7 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
 
 	sendcq = ib_alloc_cq(ia->ri_device, NULL,
 			     ep->rep_attr.cap.max_send_wr + 1,
-			     0, IB_POLL_SOFTIRQ);
+			     1, IB_POLL_WORKQUEUE);
 	if (IS_ERR(sendcq)) {
 		rc = PTR_ERR(sendcq);
 		dprintk("RPC:       %s: failed to create send CQ: %i\n",