sunrpc: Create a client/ subdirectory in the sunrpc sysfs

For network namespace separation.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

net/sunrpc/sysfs.c

@@ -2,19 +2,62 @@
 /*
  * Copyright (c) 2020 Anna Schumaker <Anna.Schumaker@Netapp.com>
  */
+#include <linux/sunrpc/clnt.h>
 #include <linux/kobject.h>
 
 static struct kset *rpc_sunrpc_kset;
+static struct kobject *rpc_sunrpc_client_kobj;
+
+static void rpc_sysfs_object_release(struct kobject *kobj)
+{
+	kfree(kobj);
+}
+
+static const struct kobj_ns_type_operations *
+rpc_sysfs_object_child_ns_type(struct kobject *kobj)
+{
+	return &net_ns_type_operations;
+}
+
+static struct kobj_type rpc_sysfs_object_type = {
+	.release = rpc_sysfs_object_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.child_ns_type = rpc_sysfs_object_child_ns_type,
+};
+
+static struct kobject *rpc_sysfs_object_alloc(const char *name,
+					      struct kset *kset,
+					      struct kobject *parent)
+{
+	struct kobject *kobj;
+
+	kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
+	if (kobj) {
+		kobj->kset = kset;
+		if (kobject_init_and_add(kobj, &rpc_sysfs_object_type,
+					 parent, "%s", name) == 0)
+			return kobj;
+		kobject_put(kobj);
+	}
+	return NULL;
+}
 
 int rpc_sysfs_init(void)
 {
 	rpc_sunrpc_kset = kset_create_and_add("sunrpc", NULL, kernel_kobj);
 	if (!rpc_sunrpc_kset)
 		return -ENOMEM;
+	rpc_sunrpc_client_kobj = rpc_sysfs_object_alloc("client", rpc_sunrpc_kset, NULL);
+	if (!rpc_sunrpc_client_kobj) {
+		kset_unregister(rpc_sunrpc_kset);
+		rpc_sunrpc_client_kobj = NULL;
+		return -ENOMEM;
+	}
 	return 0;
 }
 
 void rpc_sysfs_exit(void)
 {
+	kobject_put(rpc_sunrpc_client_kobj);
 	kset_unregister(rpc_sunrpc_kset);
 }