RDMA: Report available cdevs through RDMA_NLDEV_CMD_GET_CHARDEV

Update the struct ib_client for all modules exporting cdevs related to the
ibdevice to also implement RDMA_NLDEV_CMD_GET_CHARDEV. All cdevs are now
autoloadable and discoverable by userspace over netlink instead of relying
on sysfs.

uverbs also exposes the DRIVER_ID for drivers that are able to support
driver id binding in rdma-core.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 47 insertions, 4 deletions

diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c
index 671f07ba1fad..547090b41cfb 100644
--- a/drivers/infiniband/core/user_mad.c
+++ b/drivers/infiniband/core/user_mad.c
@@ -54,6 +54,7 @@
 
 #include <rdma/ib_mad.h>
 #include <rdma/ib_user_mad.h>
+#include <rdma/rdma_netlink.h>
 
 #include "core_priv.h"
 
@@ -1124,11 +1125,48 @@ static const struct file_operations umad_sm_fops = {
 	.llseek	 = no_llseek,
 };
 
+static int ib_umad_get_nl_info(struct ib_device *ibdev, void *client_data,
+			       struct ib_client_nl_info *res)
+{
+	struct ib_umad_device *umad_dev = client_data;
+
+	if (!rdma_is_port_valid(ibdev, res->port))
+		return -EINVAL;
+
+	res->abi = IB_USER_MAD_ABI_VERSION;
+	res->cdev = &umad_dev->ports[res->port - rdma_start_port(ibdev)].dev;
+
+	return 0;
+}
+
 static struct ib_client umad_client = {
 	.name   = "umad",
 	.add    = ib_umad_add_one,
-	.remove = ib_umad_remove_one
+	.remove = ib_umad_remove_one,
+	.get_nl_info = ib_umad_get_nl_info,
 };
+MODULE_ALIAS_RDMA_CLIENT("umad");
+
+static int ib_issm_get_nl_info(struct ib_device *ibdev, void *client_data,
+			       struct ib_client_nl_info *res)
+{
+	struct ib_umad_device *umad_dev =
+		ib_get_client_data(ibdev, &umad_client);
+
+	if (!rdma_is_port_valid(ibdev, res->port))
+		return -EINVAL;
+
+	res->abi = IB_USER_MAD_ABI_VERSION;
+	res->cdev = &umad_dev->ports[res->port - rdma_start_port(ibdev)].sm_dev;
+
+	return 0;
+}
+
+static struct ib_client issm_client = {
+	.name = "issm",
+	.get_nl_info = ib_issm_get_nl_info,
+};
+MODULE_ALIAS_RDMA_CLIENT("issm");
 
 static ssize_t ibdev_show(struct device *dev, struct device_attribute *attr,
 			  char *buf)
@@ -1387,13 +1425,17 @@ static int __init ib_umad_init(void)
 	}
 
 	ret = ib_register_client(&umad_client);
-	if (ret) {
-		pr_err("couldn't register ib_umad client\n");
+	if (ret)
 		goto out_class;
-	}
+
+	ret = ib_register_client(&issm_client);
+	if (ret)
+		goto out_client;
 
 	return 0;
 
+out_client:
+	ib_unregister_client(&umad_client);
 out_class:
 	class_unregister(&umad_class);
 
@@ -1411,6 +1453,7 @@ out:
 
 static void __exit ib_umad_cleanup(void)
 {
+	ib_unregister_client(&issm_client);
 	ib_unregister_client(&umad_client);
 	class_unregister(&umad_class);
 	unregister_chrdev_region(base_umad_dev,