nfsd: Clean up the "glue" for the nfsrdma.ko module

Move svc_reg() calls into a helper function so that the nfsrdma.ko
can call that.  Create a new nfs_extern.h as a place to put the
nfs stuff that server side NFS over RDMA needs to access, with a
prototype for the helper function and a couple of definitions that
probably shouldn't be in svc.h.

No semantics change.

MFC after:	3 months
Fixes:	7144a1d58c ("nfsd: Add glue for the nfsrdma.ko module")

sys/fs/nfsserver/nfs_nfsdkrpc.c

@@ -39,6 +39,7 @@
 #include "opt_kern_tls.h"
 
 #include <fs/nfs/nfsport.h>
+#include <fs/nfs/nfs_extern.h>
 
 #include <rpc/rpc.h>
 #include <rpc/rpcsec_gss.h>
@@ -105,7 +106,6 @@ static int nfs_proc(struct nfsrv_descript *, u_int32_t, SVCXPRT *xprt,
     struct nfsrvcache **);
 
 extern u_long sb_max_adj;
-extern int newnfs_numnfsd;
 extern time_t nfsdev_time;
 extern int nfsrv_writerpc[NFS_NPROCS];
 extern volatile int nfsrv_devidcnt;
@@ -554,6 +554,21 @@ nfssvc_loss(SVCXPRT *xprt)
 	CURVNET_RESTORE();
 }
 
+/*
+ * Register xprt with the correct versions of NFS.
+ */
+void
+nfsrv_svc_reg(SVCXPRT *xprt)
+{
+
+	if (VNET(nfs_minvers) == NFS_VER2)
+		svc_reg(xprt, NFS_PROG, NFS_VER2, nfssvc_program, NULL);
+	if (VNET(nfs_minvers) <= NFS_VER3 && VNET(nfs_maxvers) >= NFS_VER3)
+		svc_reg(xprt, NFS_PROG, NFS_VER3, nfssvc_program, NULL);
+	if (VNET(nfs_maxvers) >= NFS_VER4)
+		svc_reg(xprt, NFS_PROG, NFS_VER4, nfssvc_program, NULL);
+}
+
 /*
  * Adds a socket to the list for servicing by nfsds.
  */
@@ -585,16 +600,7 @@ nfsrvd_addsock(struct file *fp)
 		fp->f_ops = &badfileops;
 		fp->f_data = NULL;
 		xprt->xp_sockref = ++sockref;
-		if (VNET(nfs_minvers) == NFS_VER2)
-			svc_reg(xprt, NFS_PROG, NFS_VER2, nfssvc_program,
-			    NULL);
-		if (VNET(nfs_minvers) <= NFS_VER3 &&
-		    VNET(nfs_maxvers) >= NFS_VER3)
-			svc_reg(xprt, NFS_PROG, NFS_VER3, nfssvc_program,
-			    NULL);
-		if (VNET(nfs_maxvers) >= NFS_VER4)
-			svc_reg(xprt, NFS_PROG, NFS_VER4, nfssvc_program,
-			    NULL);
+		nfsrv_svc_reg(xprt);
 		if (so->so_type == SOCK_STREAM)
 			svc_loss_reg(xprt, nfssvc_loss);
 		SVC_RELEASE(xprt);

sys/fs/nfsserver/nfs_nfsdport.c

@@ -43,6 +43,7 @@
  */
 
 #include <fs/nfs/nfsport.h>
+#include <fs/nfs/nfs_extern.h>
 #include <security/mac/mac_framework.h>
 #include <sys/callout.h>
 #include <sys/filio.h>
@@ -59,7 +60,6 @@ FEATURE(nfsd, "NFSv4 server");
 
 extern u_int32_t newnfs_true, newnfs_false, newnfs_xdrneg1;
 extern int nfsrv_useacl;
-extern int newnfs_numnfsd;
 extern int nfsrv_sessionhashsize;
 extern struct nfslayouthash *nfslayouthash;
 extern int nfsrv_layouthashsize;

sys/rpc/svc.h

@@ -350,8 +350,6 @@ typedef struct __rpc_svcpool {
  */
 typedef int	svc_rdma_listen_ftype(SVCPOOL *pool, int port);
 extern svc_rdma_listen_ftype *svc_rdma_listen;
-extern int	nfsrvd_rdma_port;
-extern int	newnfs_numnfsd;
 
 /*
  * Operations defined on an SVCXPRT handle