[pnfs] [PATCH 04/10] nfs41: Backchannel bc_svc_process()

[Ricardo Labiaga]

Implement the NFSv4.1 backchannel service.  Invokes the common callback
processing logic svc_process_common() to authenticate the call and
dispatch the appropriate NFSv4.1 XDR decoder and operation procedure.
It then invokes bc_send() to send the reply over the same connection.
bc_send() is implemented in a separate patch.

At this time there is no slot validation or reply cache handling.

Signed-off-by: Ricardo Labiaga <ricardo.labiaga at netapp.com>
---
 include/linux/sunrpc/bc_xprt.h |    1 +
 net/sunrpc/sunrpc_syms.c       |    1 +
 net/sunrpc/svc.c               |   43 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 45 insertions(+), 0 deletions(-)

diff --git a/include/linux/sunrpc/bc_xprt.h b/include/linux/sunrpc/bc_xprt.h
index 8ad9337..b248f06 100644
--- a/include/linux/sunrpc/bc_xprt.h
+++ b/include/linux/sunrpc/bc_xprt.h
@@ -35,6 +35,7 @@ struct rpc_rqst *xprt_alloc_bc_request(struct rpc_xprt *xprt);
 void xprt_free_bc_request(struct rpc_rqst *req);
 int xprt_setup_backchannel(struct rpc_xprt *, unsigned int min_reqs);
 void xprt_destroy_backchannel(struct rpc_xprt *, int max_reqs);
+int bc_send(struct rpc_rqst *req);
 #endif /* CONFIG_NFS_V4_1 */
 #endif /* _LINUX_SUNRPC_BC_XPRT_H */
 
diff --git a/net/sunrpc/sunrpc_syms.c b/net/sunrpc/sunrpc_syms.c
index 928d447..dae41fd 100644
--- a/net/sunrpc/sunrpc_syms.c
+++ b/net/sunrpc/sunrpc_syms.c
@@ -72,6 +72,7 @@ EXPORT_SYMBOL(svc_exit_thread);
 EXPORT_SYMBOL(svc_destroy);
 EXPORT_SYMBOL(svc_drop);
 EXPORT_SYMBOL(svc_process);
+EXPORT_SYMBOL(bc_svc_process);
 EXPORT_SYMBOL(svc_recv);
 EXPORT_SYMBOL(svc_wake_up);
 EXPORT_SYMBOL(svc_makesock);
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index bfaefb4..e83dfd5 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -24,6 +24,7 @@
 #include <linux/sunrpc/stats.h>
 #include <linux/sunrpc/svcsock.h>
 #include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/bc_xprt.h>
 
 #define RPCDBG_FACILITY	RPCDBG_SVCDSP
 
@@ -1070,6 +1071,48 @@ svc_process(struct svc_rqst *rqstp)
 }
 
 /*
+ * Process a backchannel RPC request that arrived over an existing
+ * outbound connection
+ */
+int
+bc_svc_process(struct svc_serv *serv, struct rpc_rqst *req,
+	       struct svc_rqst *rqstp)
+{
+	struct kvec	*argv = &rqstp->rq_arg.head[0];
+	struct kvec	*resv = &rqstp->rq_res.head[0];
+	int 		error;
+
+	/* Build the svc_rqst used by the common processing routine */
+	rqstp->rq_xid = req->rq_xid;
+	rqstp->rq_prot = req->rq_xprt->prot;
+	rqstp->rq_server = serv;
+
+	rqstp->rq_addrlen = sizeof(req->rq_xprt->addr);
+	memcpy(&rqstp->rq_addr, &req->rq_xprt->addr, rqstp->rq_addrlen);
+	memcpy(&rqstp->rq_arg, &req->rq_private_buf, sizeof(rqstp->rq_arg));
+	memcpy(&rqstp->rq_res, &req->rq_snd_buf, sizeof(rqstp->rq_res));
+
+	if (rqstp->rq_prot != IPPROTO_TCP) {
+		printk(KERN_ERR "No support for Non-TCP transports!\n");
+		BUG();
+	}
+
+	/*
+	 * Skip the next two words because they've already been
+	 * processed in the trasport
+	 */
+	svc_getu32(argv);	/* XID */
+	svc_getnl(argv);	/* CALLDIR */
+
+	error = svc_process_common(rqstp, argv, resv);
+	if (error <= 0)
+		return error;
+
+	memcpy(&req->rq_snd_buf, &rqstp->rq_res, sizeof(req->rq_snd_buf));
+	return bc_send(req);
+}
+
+/*
  * Return (transport-specific) limit on the rpc payload.
  */
 u32 svc_max_payload(const struct svc_rqst *rqstp)
-- 
1.5.3.3