NFS: Fix the selection of security flavours in Kconfig

Randy Dunlap reports:

ERROR: "svc_gss_principal" [fs/nfs/nfs.ko] undefined!


because in fs/nfs/Kconfig, NFS_V4 selects RPCSEC_GSS_KRB5
and/or in fs/nfsd/Kconfig, NFSD_V4 selects RPCSEC_GSS_KRB5.

RPCSEC_GSS_KRB5 does 5 selects, but none of these is enforced/followed
by the fs/nfs[d]/Kconfig configs:

	select SUNRPC_GSS
	select CRYPTO
	select CRYPTO_MD5
	select CRYPTO_DES
	select CRYPTO_CBC

Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: J. Bruce Fields <bfields@fieldses.org>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/Kconfig

@@ -63,7 +63,6 @@ config NFS_V3_ACL
 config NFS_V4
 	bool "NFS client support for NFS version 4"
 	depends on NFS_FS
-	select RPCSEC_GSS_KRB5
 	help
 	  This option enables support for version 4 of the NFS protocol
 	  (RFC 3530) in the kernel's NFS client.

fs/nfsd/Kconfig

@@ -69,7 +69,6 @@ config NFSD_V4
 	depends on NFSD && PROC_FS && EXPERIMENTAL
 	select NFSD_V3
 	select FS_POSIX_ACL
-	select RPCSEC_GSS_KRB5
 	help
 	  This option enables support in your system's NFS server for
 	  version 4 of the NFS protocol (RFC 3530).

net/sunrpc/Kconfig

@@ -18,10 +18,11 @@ config SUNRPC_XPRT_RDMA
 	  If unsure, say N.
 
 config RPCSEC_GSS_KRB5
-	tristate "Secure RPC: Kerberos V mechanism (EXPERIMENTAL)"
-	depends on SUNRPC && EXPERIMENTAL
+	tristate
+	depends on SUNRPC && CRYPTO
+	prompt "Secure RPC: Kerberos V mechanism" if !(NFS_V4 || NFSD_V4)
+	default y
 	select SUNRPC_GSS
-	select CRYPTO
 	select CRYPTO_MD5
 	select CRYPTO_DES
 	select CRYPTO_CBC
@@ -34,7 +35,7 @@ config RPCSEC_GSS_KRB5
 	  available from http://linux-nfs.org/.  In addition, user-space
 	  Kerberos support should be installed.
 
-	  If unsure, say N.
+	  If unsure, say Y.
 
 config RPCSEC_GSS_SPKM3
 	tristate "Secure RPC: SPKM3 mechanism (EXPERIMENTAL)"