[PATCH v1 1/1] ethdev: add flow item structure size query

[Anatoly Burakov]

Add RTE_FLOW_CONV_OP_ITEM_SIZE to retrieve the fixed specification
structure size for a flow item type using the existing descriptor table.

Signed-off-by: Anatoly Burakov <anatoly.burakov at intel.com>
---
 lib/ethdev/rte_flow.c | 16 ++++++++++++++++
 lib/ethdev/rte_flow.h | 18 ++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/lib/ethdev/rte_flow.c b/lib/ethdev/rte_flow.c
index 0ebf59165d4..1b2d263331a 100644
--- a/lib/ethdev/rte_flow.c
+++ b/lib/ethdev/rte_flow.c
@@ -1266,6 +1266,22 @@ rte_flow_conv(enum rte_flow_conv_op op,
 	case RTE_FLOW_CONV_OP_ITEM_DEFAULT_MASK_PTR:
 		ret = rte_flow_conv_item_default_mask(dst, size, src, error);
 		break;
+	case RTE_FLOW_CONV_OP_ITEM_SIZE:
+	{
+		uintptr_t type = (uintptr_t)src;
+
+		if (type >= RTE_DIM(rte_flow_desc_item) ||
+				rte_flow_desc_item[type].name == NULL) {
+			ret = rte_flow_error_set(error, EINVAL,
+					RTE_FLOW_ERROR_TYPE_UNSPECIFIED, NULL,
+					"unknown item type to retrieve the size of");
+			break;
+		}
+		if (size >= sizeof(size_t))
+			*(size_t *)dst = rte_flow_desc_item[type].size;
+		ret = sizeof(size_t);
+		break;
+	}
 	default:
 		ret = rte_flow_error_set
 		(error, ENOTSUP, RTE_FLOW_ERROR_TYPE_UNSPECIFIED, NULL,
diff --git a/lib/ethdev/rte_flow.h b/lib/ethdev/rte_flow.h
index df8101e4395..3d6a56f51e3 100644
--- a/lib/ethdev/rte_flow.h
+++ b/lib/ethdev/rte_flow.h
@@ -4426,6 +4426,24 @@ enum rte_flow_conv_op {
 	 *   @code const void ** @endcode
 	 */
 	RTE_FLOW_CONV_OP_ITEM_DEFAULT_MASK_PTR,
+
+	/**
+	 * Retrieve the fixed size of an item specification structure.
+	 *
+	 * Writes the size of rte_flow_item_{name} to @p dst, or zero for
+	 * known item types without a specification structure. Does not include
+	 * variable-length or externally referenced data (for example, RAW
+	 * pattern bytes). Unknown and PMD-private item types return an error.
+	 *
+	 * No output is written if @p size is smaller than sizeof(size_t).
+	 * The return value is sizeof(size_t), not the item structure size.
+	 *
+	 * - @p src type:
+	 *   @code (const void *)(uintptr_t)enum rte_flow_item_type @endcode
+	 * - @p dst type:
+	 *   @code size_t * @endcode
+	 */
+	RTE_FLOW_CONV_OP_ITEM_SIZE,
 };
 
 /**
-- 
2.52.0