[RFC PATCH 4/7] sunrpc: Create per-rpc_clnt sysfs kobjects

[schumaker.anna@gmail.com]

From: Anna Schumaker <Anna.Schumaker@Netapp.com>

These will eventually have files placed under them for sysfs operations.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
---
 include/linux/sunrpc/clnt.h |  1 +
 net/sunrpc/clnt.c           |  5 +++
 net/sunrpc/sysfs.c          | 61 +++++++++++++++++++++++++++++++++++++
 net/sunrpc/sysfs.h          |  8 +++++
 4 files changed, 75 insertions(+)

diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
index 02e7a5863d28..503653720e18 100644
--- a/include/linux/sunrpc/clnt.h
+++ b/include/linux/sunrpc/clnt.h
@@ -71,6 +71,7 @@ struct rpc_clnt {
 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 	struct dentry		*cl_debugfs;	/* debugfs directory */
 #endif
+	void			*cl_sysfs;	/* sysfs directory */
 	/* cl_work is only needed after cl_xpi is no longer used,
 	 * and that are of similar size
 	 */
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 612f0a641f4c..02905eae5c0a 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -41,6 +41,7 @@
 #include <trace/events/sunrpc.h>
 
 #include "sunrpc.h"
+#include "sysfs.h"
 #include "netns.h"
 
 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
@@ -300,6 +301,7 @@ static int rpc_client_register(struct rpc_clnt *clnt,
 	int err;
 
 	rpc_clnt_debugfs_register(clnt);
+	rpc_netns_sysfs_setup(clnt, net);
 
 	pipefs_sb = rpc_get_sb_net(net);
 	if (pipefs_sb) {
@@ -327,6 +329,7 @@ static int rpc_client_register(struct rpc_clnt *clnt,
 out:
 	if (pipefs_sb)
 		rpc_put_sb_net(net);
+	rpc_netns_sysfs_destroy(clnt);
 	rpc_clnt_debugfs_unregister(clnt);
 	return err;
 }
@@ -733,6 +736,7 @@ int rpc_switch_client_transport(struct rpc_clnt *clnt,
 
 	rpc_unregister_client(clnt);
 	__rpc_clnt_remove_pipedir(clnt);
+	rpc_netns_sysfs_destroy(clnt);
 	rpc_clnt_debugfs_unregister(clnt);
 
 	/*
@@ -879,6 +883,7 @@ static void rpc_free_client_work(struct work_struct *work)
 	 * so they cannot be called in rpciod, so they are handled separately
 	 * here.
 	 */
+	rpc_netns_sysfs_destroy(clnt);
 	rpc_clnt_debugfs_unregister(clnt);
 	rpc_free_clid(clnt);
 	rpc_clnt_remove_pipedir(clnt);
diff --git a/net/sunrpc/sysfs.c b/net/sunrpc/sysfs.c
index afeaec79a9c7..dd298b9c13e8 100644
--- a/net/sunrpc/sysfs.c
+++ b/net/sunrpc/sysfs.c
@@ -2,7 +2,9 @@
 /*
  * Copyright (c) 2020 Anna Schumaker <Anna.Schumaker@Netapp.com>
  */
+#include <linux/sunrpc/clnt.h>
 #include <net/sock.h>
+#include "sysfs.h"
 
 struct kobject *rpc_client_kobj;
 static struct kset *rpc_client_kset;
@@ -53,8 +55,67 @@ int rpc_sysfs_init(void)
 	return 0;
 }
 
+static void rpc_netns_client_release(struct kobject *kobj)
+{
+	struct rpc_netns_client *c;
+
+	c = container_of(kobj, struct rpc_netns_client, kobject);
+	kfree(c);
+}
+
+static const void *rpc_netns_client_namespace(struct kobject *kobj)
+{
+	return container_of(kobj, struct rpc_netns_client, kobject)->net;
+}
+
+static struct kobj_type rpc_netns_client_type = {
+	.release = rpc_netns_client_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.namespace = rpc_netns_client_namespace,
+};
+
 void rpc_sysfs_exit(void)
 {
 	kobject_put(rpc_client_kobj);
 	kset_unregister(rpc_client_kset);
 }
+
+static struct rpc_netns_client *rpc_netns_client_alloc(struct kobject *parent,
+						struct net *net, int clid)
+{
+	struct rpc_netns_client *p;
+
+	p = kzalloc(sizeof(*p), GFP_KERNEL);
+	if (p) {
+		p->net = net;
+		p->kobject.kset = rpc_client_kset;
+		if (kobject_init_and_add(&p->kobject, &rpc_netns_client_type,
+					parent, "%d", clid) == 0)
+			return p;
+		kobject_put(&p->kobject);
+	}
+	return NULL;
+}
+
+void rpc_netns_sysfs_setup(struct rpc_clnt *clnt, struct net *net)
+{
+	struct rpc_netns_client *rpc_client;
+
+	rpc_client = rpc_netns_client_alloc(rpc_client_kobj, net, clnt->cl_clid);
+	if (rpc_client) {
+		clnt->cl_sysfs = rpc_client;
+		kobject_uevent(&rpc_client->kobject, KOBJ_ADD);
+	}
+}
+
+void rpc_netns_sysfs_destroy(struct rpc_clnt *clnt)
+{
+	struct rpc_netns_client *rpc_client = clnt->cl_sysfs;
+
+	if (rpc_client) {
+		kobject_uevent(&rpc_client->kobject, KOBJ_REMOVE);
+		kobject_del(&rpc_client->kobject);
+		kobject_put(&rpc_client->kobject);
+		clnt->cl_sysfs = NULL;
+	}
+}
diff --git a/net/sunrpc/sysfs.h b/net/sunrpc/sysfs.h
index 93c3cd220506..279a836594e7 100644
--- a/net/sunrpc/sysfs.h
+++ b/net/sunrpc/sysfs.h
@@ -5,9 +5,17 @@
 #ifndef __SUNRPC_SYSFS_H
 #define __SUNRPC_SYSFS_H
 
+struct rpc_netns_client {
+	struct kobject kobject;
+	struct net *net;
+};
+
 extern struct kobject *rpc_client_kobj;
 
 extern int rpc_sysfs_init(void);
 extern void rpc_sysfs_exit(void);
 
+void rpc_netns_sysfs_setup(struct rpc_clnt *clnt, struct net *net);
+void rpc_netns_sysfs_destroy(struct rpc_clnt *clnt);
+
 #endif
-- 
2.29.2