[ofa-general] [RFC,PATCH 13/20] svc: Add svc_[un]register_transport

[Tom Tucker]

Add an exported function for transport modules to [un]register themselves
with the sunrpc server side transport switch.

Signed-off-by: Tom Tucker <tom at opengridcomputing.com>
---

 include/linux/sunrpc/svcsock.h |    6 +++++
 net/sunrpc/svcsock.c           |   50 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 0 deletions(-)

diff --git a/include/linux/sunrpc/svcsock.h b/include/linux/sunrpc/svcsock.h
index 7def951..cc911ab 100644
--- a/include/linux/sunrpc/svcsock.h
+++ b/include/linux/sunrpc/svcsock.h
@@ -13,6 +13,7 @@ #include <linux/sunrpc/svc.h>
 
 struct svc_xprt {
 	const char		*xpt_name;
+	struct module		*xpt_owner;
 	int			(*xpt_recvfrom)(struct svc_rqst *rqstp);
 	int			(*xpt_sendto)(struct svc_rqst *rqstp);
 	/*
@@ -45,7 +46,10 @@ struct svc_xprt {
 	 * Accept a pending connection, for connection-oriented transports
 	 */
 	int			(*xpt_accept)(struct svc_sock *svsk);
+	/* Transport list link */
+	struct list_head	xpt_list;
 };
+extern struct list_head svc_transport_list;
 
 /*
  * RPC server socket.
@@ -102,6 +106,8 @@ #define	SK_LISTENER	11			/* listener (e.
 /*
  * Function prototypes.
  */
+int 		svc_register_transport(struct svc_xprt *xprt);
+int 		svc_unregister_transport(struct svc_xprt *xprt);
 int		svc_makesock(struct svc_serv *, int, unsigned short, int flags);
 void		svc_force_close_socket(struct svc_sock *);
 int		svc_recv(struct svc_rqst *, long);
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 6acf22f..6183951 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -91,6 +91,54 @@ static struct svc_deferred_req *svc_defe
 static int svc_deferred_recv(struct svc_rqst *rqstp);
 static struct cache_deferred_req *svc_defer(struct cache_req *req);
 
+/* List of registered transports */
+static spinlock_t svc_transport_lock = SPIN_LOCK_UNLOCKED;
+LIST_HEAD(svc_transport_list);
+
+int svc_register_transport(struct svc_xprt *xprt)
+{
+	struct svc_xprt *ops;
+	int res;
+
+	dprintk("svc: Adding svc transport '%s'\n",
+		xprt->xpt_name);
+
+	res = -EEXIST;
+	INIT_LIST_HEAD(&xprt->xpt_list);
+	spin_lock(&svc_transport_lock);
+	list_for_each_entry(ops, &svc_transport_list, xpt_list) {
+		if (xprt == ops)
+			goto out;
+	}
+	list_add_tail(&xprt->xpt_list, &svc_transport_list);
+	res = 0;
+out:
+	spin_unlock(&svc_transport_lock);
+	return res;
+}
+EXPORT_SYMBOL_GPL(svc_register_transport);
+
+int svc_unregister_transport(struct svc_xprt *xprt)
+{
+	struct svc_xprt *ops;
+	int res = 0;
+
+	dprintk("svc: Removing svc transport '%s'\n", xprt->xpt_name);
+
+	spin_lock(&svc_transport_lock);
+	list_for_each_entry(ops, &svc_transport_list, xpt_list) {
+		if (xprt == ops) {
+			list_del_init(&ops->xpt_list);
+			goto out;
+		}
+	}
+	res = -ENOENT;
+ out:
+	spin_unlock(&svc_transport_lock);
+	return res;
+}
+EXPORT_SYMBOL_GPL(svc_unregister_transport);
+
 /* apparently the "standard" is that clients close
  * idle connections after 5 minutes, servers after
  * 6 minutes
@@ -887,6 +935,7 @@ svc_udp_has_wspace(struct svc_sock *svsk
 
 static const struct svc_xprt svc_udp_xprt = {
 	.xpt_name = "udp",
+	.xpt_owner = THIS_MODULE,
 	.xpt_recvfrom = svc_udp_recvfrom,
 	.xpt_sendto = svc_udp_sendto,
 	.xpt_detach = svc_sock_detach,
@@ -1346,6 +1395,7 @@ svc_tcp_has_wspace(struct svc_sock *svsk
 
 static const struct svc_xprt svc_tcp_xprt = {
 	.xpt_name = "tcp",
+	.xpt_owner = THIS_MODULE,
 	.xpt_recvfrom = svc_tcp_recvfrom,
 	.xpt_sendto = svc_tcp_sendto,
 	.xpt_detach = svc_sock_detach,