spin_lock(&ch_index_lock);
ch = idr_find(&ch_index_idr, minor);
if (NULL == ch || scsi_device_get(ch->device)) {
spin_unlock(&ch_index_lock);
spin_lock(&ch_index_lock);
ch = idr_find(&ch_index_idr, minor);
if (NULL == ch || scsi_device_get(ch->device)) {
spin_unlock(&ch_index_lock);