3.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

commit 1d057720609ed052a6371fe1d53300e5e6328e94 upstream.

Enable the compat keyctl wrapper on s390x so that 32-bit s390 userspace can
call the keyctl() syscall.

There's an s390x assembly wrapper that truncates all the register values to
32-bits and this then calls compat_sys_keyctl() - but the latter only exists if
CONFIG_KEYS_COMPAT is enabled, and the s390 Kconfig doesn't enable it.

Without this patch, 32-bit calls to the keyctl() syscall are given an ENOSYS
error:

	[root@devel4 ~]# keyctl show
	Session Keyring
	-3: key inaccessible (Function not implemented)

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: dan@danny.cz
Cc: Carsten Otte <redacted>
Reviewed-by: Christian Borntraeger <redacted>
Cc: linux-s390@vger.kernel.org
Signed-off-by: Heiko Carstens <redacted>
Signed-off-by: Martin Schwidefsky <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/s390/Kconfig |    3 +++
 1 file changed, 3 insertions(+)

--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig

@@ -228,6 +228,9 @@ config COMPAT
 config SYSVIPC_COMPAT
 	def_bool y if COMPAT && SYSVIPC
 
+config KEYS_COMPAT
+	def_bool y if COMPAT && KEYS
+
 config AUDIT_ARCH
 	def_bool y