RDMA/mlx5: Add support for drop action in DV steering

When drop action is used the matching packet will stop processing in
steering and will be dropped. This functionality will allow users to drop
matching packets.

Link: https://lore.kernel.org/r/20200504054227.271486-1-leon@kernel.org
Signed-off-by: Daria Velikovsky <daria@mellanox.com>
Reviewed-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx5/flow.c

@@ -69,35 +69,39 @@ static const struct uverbs_attr_spec mlx5_ib_flow_type[] = {
 
 static int get_dests(struct uverbs_attr_bundle *attrs,
 		     struct mlx5_ib_flow_matcher *fs_matcher, int *dest_id,
-		     int *dest_type, struct ib_qp **qp, bool *def_miss)
+		     int *dest_type, struct ib_qp **qp, u32 *flags)
 {
 	bool dest_devx, dest_qp;
 	void *devx_obj;
-	u32 flags;
 	int err;
 
 	dest_devx = uverbs_attr_is_valid(attrs,
 					 MLX5_IB_ATTR_CREATE_FLOW_DEST_DEVX);
 	dest_qp = uverbs_attr_is_valid(attrs,
 				       MLX5_IB_ATTR_CREATE_FLOW_DEST_QP);
 
-	*def_miss = false;
-	err = uverbs_get_flags32(&flags, attrs,
-				 MLX5_IB_ATTR_CREATE_FLOW_FLAGS,
-				 MLX5_IB_ATTR_CREATE_FLOW_FLAGS_DEFAULT_MISS);
+	*flags = 0;
+	err = uverbs_get_flags32(flags, attrs, MLX5_IB_ATTR_CREATE_FLOW_FLAGS,
+				 MLX5_IB_ATTR_CREATE_FLOW_FLAGS_DEFAULT_MISS |
+					 MLX5_IB_ATTR_CREATE_FLOW_FLAGS_DROP);
 	if (err)
 		return err;
-	*def_miss = flags & MLX5_IB_ATTR_CREATE_FLOW_FLAGS_DEFAULT_MISS;
+
+	/* Both flags are not allowed */
+	if (*flags & MLX5_IB_ATTR_CREATE_FLOW_FLAGS_DEFAULT_MISS &&
+	    *flags & MLX5_IB_ATTR_CREATE_FLOW_FLAGS_DROP)
+		return -EINVAL;
 
 	if (fs_matcher->ns_type == MLX5_FLOW_NAMESPACE_BYPASS) {
-		if (dest_devx && (dest_qp || *def_miss))
+		if (dest_devx && (dest_qp || *flags))
 			return -EINVAL;
-		else if (dest_qp && *def_miss)
+		else if (dest_qp && *flags)
 			return -EINVAL;
 	}
 
-	/* Allow only DEVX object as dest when inserting to FDB */
-	if (fs_matcher->ns_type == MLX5_FLOW_NAMESPACE_FDB && !dest_devx)
+	/* Allow only DEVX object, drop as dest for FDB */
+	if (fs_matcher->ns_type == MLX5_FLOW_NAMESPACE_FDB && !(dest_devx ||
+	     (*flags & MLX5_IB_ATTR_CREATE_FLOW_FLAGS_DROP)))
 		return -EINVAL;
 
 	/* Allow only DEVX object or QP as dest when inserting to RDMA_RX */
@@ -166,7 +170,7 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_CREATE_FLOW)(
 	void *devx_obj, *cmd_in;
 	struct ib_uobject *uobj;
 	struct mlx5_ib_dev *dev;
-	bool def_miss;
+	u32 flags;
 
 	if (!capable(CAP_NET_RAW))
 		return -EPERM;
@@ -176,12 +180,15 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_CREATE_FLOW)(
 	uobj =  uverbs_attr_get_uobject(attrs, MLX5_IB_ATTR_CREATE_FLOW_HANDLE);
 	dev = mlx5_udata_to_mdev(&attrs->driver_udata);
 
-	if (get_dests(attrs, fs_matcher, &dest_id, &dest_type, &qp, &def_miss))
+	if (get_dests(attrs, fs_matcher, &dest_id, &dest_type, &qp, &flags))
 		return -EINVAL;
 
-	if (def_miss)
+	if (flags & MLX5_IB_ATTR_CREATE_FLOW_FLAGS_DEFAULT_MISS)
 		flow_act.action |= MLX5_FLOW_CONTEXT_ACTION_FWD_NEXT_NS;
 
+	if (flags & MLX5_IB_ATTR_CREATE_FLOW_FLAGS_DROP)
+		flow_act.action |= MLX5_FLOW_CONTEXT_ACTION_DROP;
+
 	len = uverbs_attr_get_uobjs_arr(attrs,
 		MLX5_IB_ATTR_CREATE_FLOW_ARR_COUNTERS_DEVX, &arr_flow_actions);
 	if (len) {

include/uapi/rdma/mlx5_user_ioctl_cmds.h

@@ -243,6 +243,7 @@ enum mlx5_ib_flow_type {
 
 enum mlx5_ib_create_flow_flags {
 	MLX5_IB_ATTR_CREATE_FLOW_FLAGS_DEFAULT_MISS = 1 << 0,
+	MLX5_IB_ATTR_CREATE_FLOW_FLAGS_DROP = 1 << 1,
 };
 
 enum mlx5_ib_create_flow_attrs {