RDMA/cma: Remove CM_ID statistics provided by rdma-cm module

Netlink statistics exported by rdma-cm never had any working user space
component published to the mailing list or to any open source
project. Canvassing various proprietary users, and the original requester,
we find that there are no real users of this interface.

This patch simply removes all occurrences of RDMA CM netlink in favour of
modern nldev implementation, which provides the same information and
accompanied by widely used user space component.

Signed-off-by: Leon Romanovsky <[e-mail]>
Reviewed-by: Steve Wise <[e-mail]>
Signed-off-by: Jason Gunthorpe <[e-mail]>

drivers/infiniband/core/cma.c

···
 	kfree(cma_dev);
 }
 
-static int cma_get_id_stats(struct sk_buff *skb, struct netlink_callback *cb)
-{
-	struct nlmsghdr *nlh;
-	struct rdma_cm_id_stats *id_stats;
-	struct rdma_id_private *id_priv;
-	struct rdma_cm_id *id = NULL;
-	struct cma_device *cma_dev;
-	int i_dev = 0, i_id = 0;
-
-	/*
-	 * We export all of the IDs as a sequence of messages.  Each
-	 * ID gets its own netlink message.
-	 */
-	mutex_lock(&lock);
-
-	list_for_each_entry(cma_dev, &dev_list, list) {
-		if (i_dev < cb->args[0]) {
-			i_dev++;
-			continue;
-		}
-
-		i_id = 0;
-		list_for_each_entry(id_priv, &cma_dev->id_list, list) {
-			if (i_id < cb->args[1]) {
-				i_id++;
-				continue;
-			}
-
-			id_stats = ibnl_put_msg(skb, &nlh, cb->nlh->nlmsg_seq,
-						sizeof *id_stats, RDMA_NL_RDMA_CM,
-						RDMA_NL_RDMA_CM_ID_STATS,
-						NLM_F_MULTI);
-			if (!id_stats)
-				goto out;
-
-			memset(id_stats, 0, sizeof *id_stats);
-			id = &id_priv->id;
-			id_stats->node_type = id->route.addr.dev_addr.dev_type;
-			id_stats->port_num = id->port_num;
-			id_stats->bound_dev_if =
-				id->route.addr.dev_addr.bound_dev_if;
-
-			if (ibnl_put_attr(skb, nlh,
-					  rdma_addr_size(cma_src_addr(id_priv)),
-					  cma_src_addr(id_priv),
-					  RDMA_NL_RDMA_CM_ATTR_SRC_ADDR))
-				goto out;
-			if (ibnl_put_attr(skb, nlh,
-					  rdma_addr_size(cma_dst_addr(id_priv)),
-					  cma_dst_addr(id_priv),
-					  RDMA_NL_RDMA_CM_ATTR_DST_ADDR))
-				goto out;
-
-			id_stats->pid	= task_pid_vnr(id_priv->res.task);
-			id_stats->port_space	= id->ps;
-			id_stats->cm_state	= id_priv->state;
-			id_stats->qp_num	= id_priv->qp_num;
-			id_stats->qp_type	= id->qp_type;
-
-			i_id++;
-			nlmsg_end(skb, nlh);
-		}
-
-		cb->args[1] = 0;
-		i_dev++;
-	}
-
-out:
-	mutex_unlock(&lock);
-	cb->args[0] = i_dev;
-	cb->args[1] = i_id;
-
-	return skb->len;
-}
-
-static const struct rdma_nl_cbs cma_cb_table[RDMA_NL_RDMA_CM_NUM_OPS] = {
-	[RDMA_NL_RDMA_CM_ID_STATS] = { .dump = cma_get_id_stats},
-};
-
 static int cma_init_net(struct net *net)
 {
 	struct cma_pernet *pernet = cma_pernet(net);
···
 	if (ret)
 		goto err;
 
-	rdma_nl_register(RDMA_NL_RDMA_CM, cma_cb_table);
 	cma_configfs_init();
 
 	return 0;
···
 static void __exit cma_cleanup(void)
 {
 	cma_configfs_exit();
-	rdma_nl_unregister(RDMA_NL_RDMA_CM);
 	ib_unregister_client(&cma_client);
 	unregister_netdevice_notifier(&cma_nb);
 	ib_sa_unregister_client(&sa_client);
 	unregister_pernet_subsys(&cma_pernet_operations);
 	destroy_workqueue(cma_wq);
 }
-
-MODULE_ALIAS_RDMA_NETLINK(RDMA_NL_RDMA_CM, 1);
 
 module_init(cma_init);
 module_exit(cma_cleanup);

drivers/infiniband/core/netlink.c

···
 static bool is_nl_msg_valid(unsigned int type, unsigned int op)
 {
 	static const unsigned int max_num_ops[RDMA_NL_NUM_CLIENTS] = {
-		[RDMA_NL_RDMA_CM] = RDMA_NL_RDMA_CM_NUM_OPS,
 		[RDMA_NL_IWCM] = RDMA_NL_IWPM_NUM_OPS,
 		[RDMA_NL_LS] = RDMA_NL_LS_NUM_OPS,
 		[RDMA_NL_NLDEV] = RDMA_NLDEV_NUM_OPS,
···
 		return -EINVAL;
 	}
 	/* FIXME: Convert IWCM to properly handle doit callbacks */
-	if ((nlh->nlmsg_flags & NLM_F_DUMP) || index == RDMA_NL_RDMA_CM ||
-	    index == RDMA_NL_IWCM) {
+	if ((nlh->nlmsg_flags & NLM_F_DUMP) || index == RDMA_NL_IWCM) {
 		struct netlink_dump_control c = {
 			.dump = cb_table[op].dump,
 		};

include/uapi/rdma/rdma_netlink.h

···
 #include <linux/types.h>
 
 enum {
-	RDMA_NL_RDMA_CM = 1,
-	RDMA_NL_IWCM,
+	RDMA_NL_IWCM = 2,
 	RDMA_NL_RSVD,
 	RDMA_NL_LS,	/* RDMA Local Services */
 	RDMA_NL_NLDEV,	/* RDMA device interface */
···
 };
 
 enum {
-	RDMA_NL_GROUP_CM = 1,
-	RDMA_NL_GROUP_IWPM,
+	RDMA_NL_GROUP_IWPM = 2,
 	RDMA_NL_GROUP_LS,
 	RDMA_NL_NUM_GROUPS
 };
···
 #define RDMA_NL_GET_CLIENT(type) ((type & (((1 << 6) - 1) << 10)) >> 10)
 #define RDMA_NL_GET_OP(type) (type & ((1 << 10) - 1))
 #define RDMA_NL_GET_TYPE(client, op) ((client << 10) + op)
-
-enum {
-	RDMA_NL_RDMA_CM_ID_STATS = 0,
-	RDMA_NL_RDMA_CM_NUM_OPS
-};
-
-enum {
-	RDMA_NL_RDMA_CM_ATTR_SRC_ADDR = 1,
-	RDMA_NL_RDMA_CM_ATTR_DST_ADDR,
-	RDMA_NL_RDMA_CM_NUM_ATTR,
-};
 
 /* The minimum version that the iwpm kernel supports */
 #define IWPM_UABI_VERSION_MIN	3