svcrdma: Add backward direction service for RPC/RDMA transport

On NFSv4.1 mount points, the Linux NFS client uses this transport
endpoint to receive backward direction calls and route replies back
to the NFSv4.1 server.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: "J. Bruce Fields" <bfields@fieldses.org>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Tested-By: Devesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index 7ccc961..fb4013e 100644 (file)
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -228,9 +228,13 @@ extern void svc_rdma_put_frmr(struct svcxprt_rdma *,
                              struct svc_rdma_fastreg_mr *);
 extern void svc_sq_reap(struct svcxprt_rdma *);
 extern void svc_rq_reap(struct svcxprt_rdma *);
-extern struct svc_xprt_class svc_rdma_class;
 extern void svc_rdma_prep_reply_hdr(struct svc_rqst *);
 
+extern struct svc_xprt_class svc_rdma_class;
+#ifdef CONFIG_SUNRPC_BACKCHANNEL
+extern struct svc_xprt_class svc_rdma_bc_class;
+#endif
+
 /* svc_rdma.c */
 extern int svc_rdma_init(void);
 extern void svc_rdma_cleanup(void);

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 3f79c4a..82c0839 100644 (file)
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -158,6 +158,7 @@ enum xprt_transports {
        XPRT_TRANSPORT_TCP      = IPPROTO_TCP,
        XPRT_TRANSPORT_BC_TCP   = IPPROTO_TCP | XPRT_TRANSPORT_BC,
        XPRT_TRANSPORT_RDMA     = 256,
+       XPRT_TRANSPORT_BC_RDMA  = XPRT_TRANSPORT_RDMA | XPRT_TRANSPORT_BC,
        XPRT_TRANSPORT_LOCAL    = 257,
 };
 

diff --git a/net/sunrpc/xprtrdma/svc_rdma.c b/net/sunrpc/xprtrdma/svc_rdma.c
index 2cd252f..1b7051b 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma.c
+++ b/net/sunrpc/xprtrdma/svc_rdma.c
@@ -239,6 +239,9 @@ void svc_rdma_cleanup(void)
                unregister_sysctl_table(svcrdma_table_header);
                svcrdma_table_header = NULL;
        }
+#if defined(CONFIG_SUNRPC_BACKCHANNEL)
+       svc_unreg_xprt_class(&svc_rdma_bc_class);
+#endif
        svc_unreg_xprt_class(&svc_rdma_class);
        kmem_cache_destroy(svc_rdma_map_cachep);
        kmem_cache_destroy(svc_rdma_ctxt_cachep);
@@ -286,6 +289,9 @@ int svc_rdma_init(void)
 
        /* Register RDMA with the SVC transport switch */
        svc_reg_xprt_class(&svc_rdma_class);
+#if defined(CONFIG_SUNRPC_BACKCHANNEL)
+       svc_reg_xprt_class(&svc_rdma_bc_class);
+#endif
        return 0;
  err1:
        kmem_cache_destroy(svc_rdma_map_cachep);

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index fcc3eb8..a133b1e 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -56,6 +56,7 @@
 
 #define RPCDBG_FACILITY        RPCDBG_SVCXPRT
 
+static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *, int);
 static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
                                        struct net *net,
                                        struct sockaddr *sa, int salen,
@@ -95,6 +96,63 @@ struct svc_xprt_class svc_rdma_class = {
        .xcl_ident = XPRT_TRANSPORT_RDMA,
 };
 
+#if defined(CONFIG_SUNRPC_BACKCHANNEL)
+static struct svc_xprt *svc_rdma_bc_create(struct svc_serv *, struct net *,
+                                          struct sockaddr *, int, int);
+static void svc_rdma_bc_detach(struct svc_xprt *);
+static void svc_rdma_bc_free(struct svc_xprt *);
+
+static struct svc_xprt_ops svc_rdma_bc_ops = {
+       .xpo_create = svc_rdma_bc_create,
+       .xpo_detach = svc_rdma_bc_detach,
+       .xpo_free = svc_rdma_bc_free,
+       .xpo_prep_reply_hdr = svc_rdma_prep_reply_hdr,
+       .xpo_secure_port = svc_rdma_secure_port,
+};
+
+struct svc_xprt_class svc_rdma_bc_class = {
+       .xcl_name = "rdma-bc",
+       .xcl_owner = THIS_MODULE,
+       .xcl_ops = &svc_rdma_bc_ops,
+       .xcl_max_payload = (1024 - RPCRDMA_HDRLEN_MIN)
+};
+
+static struct svc_xprt *svc_rdma_bc_create(struct svc_serv *serv,
+                                          struct net *net,
+                                          struct sockaddr *sa, int salen,
+                                          int flags)
+{
+       struct svcxprt_rdma *cma_xprt;
+       struct svc_xprt *xprt;
+
+       cma_xprt = rdma_create_xprt(serv, 0);
+       if (!cma_xprt)
+               return ERR_PTR(-ENOMEM);
+       xprt = &cma_xprt->sc_xprt;
+
+       svc_xprt_init(net, &svc_rdma_bc_class, xprt, serv);
+       serv->sv_bc_xprt = xprt;
+
+       dprintk("svcrdma: %s(%p)\n", __func__, xprt);
+       return xprt;
+}
+
+static void svc_rdma_bc_detach(struct svc_xprt *xprt)
+{
+       dprintk("svcrdma: %s(%p)\n", __func__, xprt);
+}
+
+static void svc_rdma_bc_free(struct svc_xprt *xprt)
+{
+       struct svcxprt_rdma *rdma =
+               container_of(xprt, struct svcxprt_rdma, sc_xprt);
+
+       dprintk("svcrdma: %s(%p)\n", __func__, xprt);
+       if (xprt)
+               kfree(rdma);
+}
+#endif /* CONFIG_SUNRPC_BACKCHANNEL */
+
 struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
 {
        struct svc_rdma_op_ctxt *ctxt;