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>

drivers/infiniband/core/device.c

@@ -2428,6 +2428,9 @@ void ib_set_device_ops(struct ib_device *dev, const struct ib_device_ops *ops)
 	if (ops->uverbs_abi_ver)
 		dev_ops->uverbs_abi_ver = ops->uverbs_abi_ver;
 
+	dev_ops->uverbs_no_driver_id_binding |=
+		ops->uverbs_no_driver_id_binding;
+
 	SET_DEVICE_OP(dev_ops, add_gid);
 	SET_DEVICE_OP(dev_ops, advise_mr);
 	SET_DEVICE_OP(dev_ops, alloc_dm);

drivers/infiniband/core/nldev.c

@@ -126,6 +126,7 @@ static const struct nla_policy nldev_policy[RDMA_NLDEV_ATTR_MAX] = {
 				    .len = 128 },
 	[RDMA_NLDEV_ATTR_CHARDEV_NAME]		= { .type = NLA_NUL_STRING,
 				    .len = RDMA_NLDEV_ATTR_ENTRY_STRLEN },
+	[RDMA_NLDEV_ATTR_UVERBS_DRIVER_ID]	= { .type = NLA_U32 },
 };
 
 static int put_driver_name_print_type(struct sk_buff *msg, const char *name,

drivers/infiniband/core/ucma.c

@@ -52,6 +52,8 @@
 #include <rdma/rdma_cm_ib.h>
 #include <rdma/ib_addr.h>
 #include <rdma/ib.h>
+#include <rdma/rdma_netlink.h>
+#include "core_priv.h"
 
 MODULE_AUTHOR("Sean Hefty");
 MODULE_DESCRIPTION("RDMA Userspace Connection Manager Access");
@@ -1788,6 +1790,19 @@ static struct miscdevice ucma_misc = {
 	.fops		= &ucma_fops,
 };
 
+static int ucma_get_global_nl_info(struct ib_client_nl_info *res)
+{
+	res->abi = RDMA_USER_CM_ABI_VERSION;
+	res->cdev = ucma_misc.this_device;
+	return 0;
+}
+
+static struct ib_client rdma_cma_client = {
+	.name = "rdma_cm",
+	.get_global_nl_info = ucma_get_global_nl_info,
+};
+MODULE_ALIAS_RDMA_CLIENT("rdma_cm");
+
 static ssize_t show_abi_version(struct device *dev,
 				struct device_attribute *attr,
 				char *buf)
@@ -1816,7 +1831,14 @@ static int __init ucma_init(void)
 		ret = -ENOMEM;
 		goto err2;
 	}
+
+	ret = ib_register_client(&rdma_cma_client);
+	if (ret)
+		goto err3;
+
 	return 0;
+err3:
+	unregister_net_sysctl_table(ucma_ctl_table_hdr);
 err2:
 	device_remove_file(ucma_misc.this_device, &dev_attr_abi_version);
 err1:
@@ -1826,6 +1848,7 @@ err1:
 
 static void __exit ucma_cleanup(void)
 {
+	ib_unregister_client(&rdma_cma_client);
 	unregister_net_sysctl_table(ucma_ctl_table_hdr);
 	device_remove_file(ucma_misc.this_device, &dev_attr_abi_version);
 	misc_deregister(&ucma_misc);

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,

drivers/infiniband/core/uverbs_main.c

@@ -51,6 +51,7 @@
 
 #include <rdma/ib.h>
 #include <rdma/uverbs_std_types.h>
+#include <rdma/rdma_netlink.h>
 
 #include "uverbs.h"
 #include "core_priv.h"
@@ -1148,12 +1149,41 @@ static const struct file_operations uverbs_mmap_fops = {
 	.compat_ioctl = ib_uverbs_ioctl,
 };
 
+static int ib_uverbs_get_nl_info(struct ib_device *ibdev, void *client_data,
+				 struct ib_client_nl_info *res)
+{
+	struct ib_uverbs_device *uverbs_dev = client_data;
+	int ret;
+
+	if (res->port != -1)
+		return -EINVAL;
+
+	res->abi = ibdev->ops.uverbs_abi_ver;
+	res->cdev = &uverbs_dev->dev;
+
+	/*
+	 * To support DRIVER_ID binding in userspace some of the driver need
+	 * upgrading to expose their PCI dependent revision information
+	 * through get_context instead of relying on modalias matching. When
+	 * the drivers are fixed they can drop this flag.
+	 */
+	if (!ibdev->ops.uverbs_no_driver_id_binding) {
+		ret = nla_put_u32(res->nl_msg, RDMA_NLDEV_ATTR_UVERBS_DRIVER_ID,
+				  ibdev->ops.driver_id);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
 static struct ib_client uverbs_client = {
 	.name   = "uverbs",
 	.no_kverbs_req = true,
 	.add    = ib_uverbs_add_one,
-	.remove = ib_uverbs_remove_one
+	.remove = ib_uverbs_remove_one,
+	.get_nl_info = ib_uverbs_get_nl_info,
 };
+MODULE_ALIAS_RDMA_CLIENT("uverbs");
 
 static ssize_t ibdev_show(struct device *device, struct device_attribute *attr,
 			  char *buf)