xprtrdma: fix pointer derefs in error cases of rpcrdma_ep_create

If there are failures then we must not leave the non-NULL pointers with
the error value, otherwise `rpcrdma_ep_destroy` gets confused and tries
free them, resulting in an Oops.

Signed-off-by: Dan Aloni <dan.aloni@vastdata.com>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net/sunrpc/xprtrdma/verbs.c

@@ -413,6 +413,7 @@ static int rpcrdma_ep_create(struct rpcrdma_xprt *r_xprt)
 					      IB_POLL_WORKQUEUE);
 	if (IS_ERR(ep->re_attr.send_cq)) {
 		rc = PTR_ERR(ep->re_attr.send_cq);
+		ep->re_attr.send_cq = NULL;
 		goto out_destroy;
 	}
 
@@ -421,6 +422,7 @@ static int rpcrdma_ep_create(struct rpcrdma_xprt *r_xprt)
 					      IB_POLL_WORKQUEUE);
 	if (IS_ERR(ep->re_attr.recv_cq)) {
 		rc = PTR_ERR(ep->re_attr.recv_cq);
+		ep->re_attr.recv_cq = NULL;
 		goto out_destroy;
 	}
 	ep->re_receive_count = 0;
@@ -459,6 +461,7 @@ static int rpcrdma_ep_create(struct rpcrdma_xprt *r_xprt)
 	ep->re_pd = ib_alloc_pd(device, 0);
 	if (IS_ERR(ep->re_pd)) {
 		rc = PTR_ERR(ep->re_pd);
+		ep->re_pd = NULL;
 		goto out_destroy;
 	}