sunrpc: add add sysfs directory per xprt under each xprt_switch

Add individual transport directories under each transport switch
group. For instance, for each nconnect=X connections there will be
a transport directory. Naming conventions also identifies transport
type -- xprt-<id>-<type> where type is udp, tcp, rdma, local, bc.
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

include/linux/sunrpc/xprt.h

@@ -183,6 +183,7 @@ enum xprt_transports {
 	XPRT_TRANSPORT_LOCAL	= 257,
 };
 
+struct rpc_sysfs_xprt;
 struct rpc_xprt {
 	struct kref		kref;		/* Reference count */
 	const struct rpc_xprt_ops *ops;		/* transport methods */
@@ -291,6 +292,7 @@ struct rpc_xprt {
 #endif
 	struct rcu_head		rcu;
 	const struct xprt_class	*xprt_class;
+	struct rpc_sysfs_xprt	*xprt_sysfs;
 };
 
 #if defined(CONFIG_SUNRPC_BACKCHANNEL)

net/sunrpc/sysfs.c

@@ -82,6 +82,14 @@ static void rpc_sysfs_xprt_switch_release(struct kobject *kobj)
 	kfree(xprt_switch);
 }
 
+static void rpc_sysfs_xprt_release(struct kobject *kobj)
+{
+	struct rpc_sysfs_xprt *xprt;
+
+	xprt = container_of(kobj, struct rpc_sysfs_xprt, kobject);
+	kfree(xprt);
+}
+
 static const void *rpc_sysfs_client_namespace(struct kobject *kobj)
 {
 	return container_of(kobj, struct rpc_sysfs_client, kobject)->net;
@@ -92,6 +100,12 @@ static const void *rpc_sysfs_xprt_switch_namespace(struct kobject *kobj)
 	return container_of(kobj, struct rpc_sysfs_xprt_switch, kobject)->net;
 }
 
+static const void *rpc_sysfs_xprt_namespace(struct kobject *kobj)
+{
+	return container_of(kobj, struct rpc_sysfs_xprt,
+			    kobject)->xprt->xprt_net;
+}
+
 static struct kobj_type rpc_sysfs_client_type = {
 	.release = rpc_sysfs_client_release,
 	.sysfs_ops = &kobj_sysfs_ops,
@@ -104,6 +118,12 @@ static struct kobj_type rpc_sysfs_xprt_switch_type = {
 	.namespace = rpc_sysfs_xprt_switch_namespace,
 };
 
+static struct kobj_type rpc_sysfs_xprt_type = {
+	.release = rpc_sysfs_xprt_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.namespace = rpc_sysfs_xprt_namespace,
+};
+
 void rpc_sysfs_exit(void)
 {
 	kobject_put(rpc_sunrpc_client_kobj);
@@ -151,6 +171,25 @@ rpc_sysfs_xprt_switch_alloc(struct kobject *parent,
 	return NULL;
 }
 
+static struct rpc_sysfs_xprt *rpc_sysfs_xprt_alloc(struct kobject *parent,
+						   struct rpc_xprt *xprt,
+						   gfp_t gfp_flags)
+{
+	struct rpc_sysfs_xprt *p;
+
+	p = kzalloc(sizeof(*p), gfp_flags);
+	if (!p)
+		goto out;
+	p->kobject.kset = rpc_sunrpc_kset;
+	if (kobject_init_and_add(&p->kobject, &rpc_sysfs_xprt_type,
+				 parent, "xprt-%d-%s", xprt->id,
+				 xprt->address_strings[RPC_DISPLAY_PROTO]) == 0)
+		return p;
+	kobject_put(&p->kobject);
+out:
+	return NULL;
+}
+
 void rpc_sysfs_client_setup(struct rpc_clnt *clnt,
 			    struct rpc_xprt_switch *xprt_switch,
 			    struct net *net)
@@ -199,6 +238,22 @@ void rpc_sysfs_xprt_switch_setup(struct rpc_xprt_switch *xprt_switch,
 	}
 }
 
+void rpc_sysfs_xprt_setup(struct rpc_xprt_switch *xprt_switch,
+			  struct rpc_xprt *xprt,
+			  gfp_t gfp_flags)
+{
+	struct rpc_sysfs_xprt *rpc_xprt;
+	struct rpc_sysfs_xprt_switch *switch_obj =
+		(struct rpc_sysfs_xprt_switch *)xprt_switch->xps_sysfs;
+
+	rpc_xprt = rpc_sysfs_xprt_alloc(&switch_obj->kobject, xprt, gfp_flags);
+	if (rpc_xprt) {
+		xprt->xprt_sysfs = rpc_xprt;
+		rpc_xprt->xprt = xprt;
+		kobject_uevent(&rpc_xprt->kobject, KOBJ_ADD);
+	}
+}
+
 void rpc_sysfs_client_destroy(struct rpc_clnt *clnt)
 {
 	struct rpc_sysfs_client *rpc_client = clnt->cl_sysfs;
@@ -225,3 +280,15 @@ void rpc_sysfs_xprt_switch_destroy(struct rpc_xprt_switch *xprt_switch)
 		xprt_switch->xps_sysfs = NULL;
 	}
 }
+
+void rpc_sysfs_xprt_destroy(struct rpc_xprt *xprt)
+{
+	struct rpc_sysfs_xprt *rpc_xprt = xprt->xprt_sysfs;
+
+	if (rpc_xprt) {
+		kobject_uevent(&rpc_xprt->kobject, KOBJ_REMOVE);
+		kobject_del(&rpc_xprt->kobject);
+		kobject_put(&rpc_xprt->kobject);
+		xprt->xprt_sysfs = NULL;
+	}
+}

net/sunrpc/sysfs.h

@@ -19,6 +19,11 @@ struct rpc_sysfs_xprt_switch {
 	struct rpc_xprt *xprt;
 };
 
+struct rpc_sysfs_xprt {
+	struct kobject kobject;
+	struct rpc_xprt *xprt;
+};
+
 int rpc_sysfs_init(void);
 void rpc_sysfs_exit(void);
 
@@ -29,5 +34,8 @@ void rpc_sysfs_client_destroy(struct rpc_clnt *clnt);
 void rpc_sysfs_xprt_switch_setup(struct rpc_xprt_switch *xprt_switch,
 				 struct rpc_xprt *xprt, gfp_t gfp_flags);
 void rpc_sysfs_xprt_switch_destroy(struct rpc_xprt_switch *xprt);
+void rpc_sysfs_xprt_setup(struct rpc_xprt_switch *xprt_switch,
+			  struct rpc_xprt *xprt, gfp_t gfp_flags);
+void rpc_sysfs_xprt_destroy(struct rpc_xprt *xprt);
 
 #endif

net/sunrpc/xprtmultipath.c

@@ -57,6 +57,7 @@ void rpc_xprt_switch_add_xprt(struct rpc_xprt_switch *xps,
 	if (xps->xps_net == xprt->xprt_net || xps->xps_net == NULL)
 		xprt_switch_add_xprt_locked(xps, xprt);
 	spin_unlock(&xps->xps_lock);
+	rpc_sysfs_xprt_setup(xps, xprt, GFP_KERNEL);
 }
 
 static void xprt_switch_remove_xprt_locked(struct rpc_xprt_switch *xps,
@@ -85,6 +86,7 @@ void rpc_xprt_switch_remove_xprt(struct rpc_xprt_switch *xps,
 	spin_lock(&xps->xps_lock);
 	xprt_switch_remove_xprt_locked(xps, xprt);
 	spin_unlock(&xps->xps_lock);
+	rpc_sysfs_xprt_destroy(xprt);
 	xprt_put(xprt);
 }
 
@@ -137,6 +139,7 @@ struct rpc_xprt_switch *xprt_switch_alloc(struct rpc_xprt *xprt,
 		xps->xps_iter_ops = &rpc_xprt_iter_singular;
 		rpc_sysfs_xprt_switch_setup(xps, xprt, gfp_flags);
 		xprt_switch_add_xprt_locked(xps, xprt);
+		rpc_sysfs_xprt_setup(xps, xprt, gfp_flags);
 	}
 
 	return xps;
@@ -152,6 +155,7 @@ static void xprt_switch_free_entries(struct rpc_xprt_switch *xps)
 				struct rpc_xprt, xprt_switch);
 		xprt_switch_remove_xprt_locked(xps, xprt);
 		spin_unlock(&xps->xps_lock);
+		rpc_sysfs_xprt_destroy(xprt);
 		xprt_put(xprt);
 		spin_lock(&xps->xps_lock);
 	}