RDMA/nldev: Reshuffle the code to avoid need to rebind QP in error path

Properly unwind QP counter rebinding in case of failure.

Trying to rebind the counter after unbiding it is not going to work
reliably, move the unbind to the end so it doesn't have to be unwound.

Fixes: b389327 ("RDMA/nldev: Allow counter manual mode configration through RDMA netlink")
Link: https://lore.kernel.org/r/20191002115627.16740-1-leon@kernel.org
Reviewed-by: Mark Zhang <markz@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/nldev.c

@@ -1787,10 +1787,6 @@ static int nldev_stat_del_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
 
 	cntn = nla_get_u32(tb[RDMA_NLDEV_ATTR_STAT_COUNTER_ID]);
 	qpn = nla_get_u32(tb[RDMA_NLDEV_ATTR_RES_LQPN]);
-	ret = rdma_counter_unbind_qpn(device, port, qpn, cntn);
-	if (ret)
-		goto err_unbind;
-
 	if (fill_nldev_handle(msg, device) ||
 	    nla_put_u32(msg, RDMA_NLDEV_ATTR_PORT_INDEX, port) ||
 	    nla_put_u32(msg, RDMA_NLDEV_ATTR_STAT_COUNTER_ID, cntn) ||
@@ -1799,13 +1795,15 @@ static int nldev_stat_del_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
 		goto err_fill;
 	}
 
+	ret = rdma_counter_unbind_qpn(device, port, qpn, cntn);
+	if (ret)
+		goto err_fill;
+
 	nlmsg_end(msg, nlh);
 	ib_device_put(device);
 	return rdma_nl_unicast(sock_net(skb->sk), msg, NETLINK_CB(skb).portid);
 
 err_fill:
-	rdma_counter_bind_qpn(device, port, qpn, cntn);
-err_unbind:
 	nlmsg_free(msg);
 err:
 	ib_device_put(device);