diff --git a/include/scsi-lowlevel.h b/include/scsi-lowlevel.h
index d25f905..9075d04 100644
--- a/include/scsi-lowlevel.h
+++ b/include/scsi-lowlevel.h
@@ -176,9 +176,6 @@ struct scsi_readtoc_list {
 	struct scsi_readtoc_desc desc[0];
 };
 
-struct scsi_preventallow_params {
-	int prevent;
-};
 struct scsi_orwrite_params {
 	uint64_t lba;
 	uint32_t num_blocks;
@@ -280,7 +277,6 @@ struct scsi_task {
 	int expxferlen;
 	unsigned char cdb[SCSI_CDB_MAX_SIZE];
 	union {
-		struct scsi_preventallow_params    preventallow;
 		struct scsi_orwrite_params         orwrite;
 		struct scsi_compareandwrite_params compareandwrite;
 		struct scsi_writeverify10_params   writeverify10;
diff --git a/lib/scsi-lowlevel.c b/lib/scsi-lowlevel.c
index 2f70aa9..667c4ec 100644
--- a/lib/scsi-lowlevel.c
+++ b/lib/scsi-lowlevel.c
@@ -1894,8 +1894,6 @@ scsi_cdb_preventallow(int prevent)
 	task->xfer_dir   = SCSI_XFER_NONE;
 	task->expxferlen = 0;
 
-	task->params.preventallow.prevent = prevent;
-
 	return task;
 }