[RFC PATCH 5/7] sunrpc: Create a per-rpc_clnt file for managing the IP address

[schumaker.anna@gmail.com]

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

And since we're using IP here, restrict to only creating sysfs files for
TCP and RDMA connections.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
---
 net/sunrpc/sysfs.c | 32 ++++++++++++++++++++++++++++++++
 net/sunrpc/sysfs.h |  1 +
 2 files changed, 33 insertions(+)

diff --git a/net/sunrpc/sysfs.c b/net/sunrpc/sysfs.c
index dd298b9c13e8..537d83635670 100644
--- a/net/sunrpc/sysfs.c
+++ b/net/sunrpc/sysfs.c
@@ -3,6 +3,7 @@
  * Copyright (c) 2020 Anna Schumaker <Anna.Schumaker@Netapp.com>
  */
 #include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/addr.h>
 #include <net/sock.h>
 #include "sysfs.h"
 
@@ -55,6 +56,23 @@ int rpc_sysfs_init(void)
 	return 0;
 }
 
+static ssize_t rpc_netns_address_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct rpc_netns_client *c = container_of(kobj,
+				struct rpc_netns_client, kobject);
+	struct rpc_clnt *clnt = c->clnt;
+	struct rpc_xprt *xprt = rcu_dereference(clnt->cl_xprt);
+
+	return rpc_ntop((struct sockaddr *)&xprt->addr, buf, PAGE_SIZE);
+}
+
+static ssize_t rpc_netns_address_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	return count;
+}
+
 static void rpc_netns_client_release(struct kobject *kobj)
 {
 	struct rpc_netns_client *c;
@@ -68,8 +86,17 @@ static const void *rpc_netns_client_namespace(struct kobject *kobj)
 	return container_of(kobj, struct rpc_netns_client, kobject)->net;
 }
 
+static struct kobj_attribute rpc_netns_client_address = __ATTR(address,
+		0644, rpc_netns_address_show, rpc_netns_address_store);
+
+static struct attribute *rpc_netns_client_attrs[] = {
+	&rpc_netns_client_address.attr,
+	NULL,
+};
+
 static struct kobj_type rpc_netns_client_type = {
 	.release = rpc_netns_client_release,
+	.default_attrs = rpc_netns_client_attrs,
 	.sysfs_ops = &kobj_sysfs_ops,
 	.namespace = rpc_netns_client_namespace,
 };
@@ -100,10 +127,15 @@ static struct rpc_netns_client *rpc_netns_client_alloc(struct kobject *parent,
 void rpc_netns_sysfs_setup(struct rpc_clnt *clnt, struct net *net)
 {
 	struct rpc_netns_client *rpc_client;
+	struct rpc_xprt *xprt = rcu_dereference(clnt->cl_xprt);
+
+	if (!(xprt->prot & (IPPROTO_TCP | XPRT_TRANSPORT_RDMA)))
+		return;
 
 	rpc_client = rpc_netns_client_alloc(rpc_client_kobj, net, clnt->cl_clid);
 	if (rpc_client) {
 		clnt->cl_sysfs = rpc_client;
+		rpc_client->clnt = clnt;
 		kobject_uevent(&rpc_client->kobject, KOBJ_ADD);
 	}
 }
diff --git a/net/sunrpc/sysfs.h b/net/sunrpc/sysfs.h
index 279a836594e7..137a12c87954 100644
--- a/net/sunrpc/sysfs.h
+++ b/net/sunrpc/sysfs.h
@@ -8,6 +8,7 @@
 struct rpc_netns_client {
 	struct kobject kobject;
 	struct net *net;
+	struct rpc_clnt *clnt;
 };
 
 extern struct kobject *rpc_client_kobj;
-- 
2.29.2