fixed the following sparse warning by adding proper cast:
drivers/staging//lustre/lustre/obdclass/obd_config.c:1055:74: warning: incorrect type in argument 2 (different address spaces)
drivers/staging//lustre/lustre/obdclass/obd_config.c:1055:74:    expected char const [noderef] <asn:1>*<noident>
drivers/staging//lustre/lustre/obdclass/obd_config.c:1055:74:    got char *[assigned] sval
Signed-off-by: Mario Bambagini <mario.bambagini@gmail.com>
Acked-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 
                                        oldfs = get_fs();
                                        set_fs(KERNEL_DS);
-                                       rc = var->fops->write(&fakefile, sval,
+                                       rc = var->fops->write(&fakefile,
+                                               (const char __user *)sval,
                                                                vallen, NULL);
                                        set_fs(oldfs);
                                }