svc: Add an svc transport class

The transport class (svc_xprt_class) represents a type of transport, e.g.
udp, tcp, rdma.  A transport class has a unique name and a set of transport
operations kept in the svc_xprt_ops structure.

A transport class can be dynamically registered and unregisterd. The
svc_xprt_class represents the module that implements the transport
type and keeps reference counts on the module to avoid unloading while
there are active users.

The endpoint (svc_xprt) is a generic, transport independent endpoint that can
be used to send and receive data for an RPC service. It inherits it's
operations from the transport class.

A transport driver module registers and unregisters itself with svc sunrpc
by calling svc_reg_xprt_class, and svc_unreg_xprt_class respectively.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Acked-by: Neil Brown <neilb@suse.de>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Greg Banks <gnb@sgi.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

2 files changed, 32 insertions, 0 deletions

diff --git a/include/linux/sunrpc/debug.h b/include/linux/sunrpc/debug.h
index 3912cf16361..092fcfa9ceb 100644
--- a/include/linux/sunrpc/debug.h
+++ b/include/linux/sunrpc/debug.h
@@ -21,6 +21,7 @@
 #define RPCDBG_SCHED            0x0040
 #define RPCDBG_TRANS            0x0080
 #define RPCDBG_SVCSOCK          0x0100
+#define RPCDBG_SVCXPRT          0x0100
 #define RPCDBG_SVCDSP           0x0200
 #define RPCDBG_MISC             0x0400
 #define RPCDBG_CACHE            0x0800
diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
new file mode 100644
index 00000000000..fe8e787bb95
--- /dev/null
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -0,0 +1,31 @@
+/*
+ * linux/include/linux/sunrpc/svc_xprt.h
+ *
+ * RPC server transport I/O
+ */
+
+#ifndef SUNRPC_SVC_XPRT_H
+#define SUNRPC_SVC_XPRT_H
+
+#include <linux/sunrpc/svc.h>
+
+struct svc_xprt_ops {
+};
+
+struct svc_xprt_class {
+        const char              *xcl_name;
+        struct module           *xcl_owner;
+        struct svc_xprt_ops     *xcl_ops;
+        struct list_head        xcl_list;
+};
+
+struct svc_xprt {
+        struct svc_xprt_class   *xpt_class;
+        struct svc_xprt_ops     *xpt_ops;
+};
+
+int     svc_reg_xprt_class(struct svc_xprt_class *);
+void    svc_unreg_xprt_class(struct svc_xprt_class *);
+void    svc_xprt_init(struct svc_xprt_class *, struct svc_xprt *);
+
+#endif /* SUNRPC_SVC_XPRT_H */