[RFC] net/hns3: clarify handling of crc reinsert

[Stephen Hemminger <stephen@networkplumber.org>]

Use a static assert rather than a comment to express why
there will be space in the buffer.  Use memcpy() rather
than rte_memcpy().

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 drivers/net/hns3/hns3_rxtx.c | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/drivers/net/hns3/hns3_rxtx.c b/drivers/net/hns3/hns3_rxtx.c
index 861511547d..9272584d24 100644
--- a/drivers/net/hns3/hns3_rxtx.c
+++ b/drivers/net/hns3/hns3_rxtx.c
@@ -2449,6 +2449,15 @@ hns3_need_recalculate_crc(struct hns3_rx_queue *rxq, struct rte_mbuf *m)
 	return true;
 }
 
+/*
+ * The hns3 driver requires that mbuf size must be at least 512B.
+ * When CRC is stripped by hardware, the pkt_len must be less than
+ * or equal to 60B. Therefore, the space of the mbuf is enough
+ * to insert the CRC.
+ */
+static_assert(HNS3_KEEP_CRC_OK_MIN_PKT_LEN < HNS3_MIN_BD_BUF_SIZE,
+	      "buffer size too small to insert CRC");
+
 static inline void
 hns3_recalculate_crc(struct rte_mbuf *m)
 {
@@ -2459,18 +2468,13 @@ hns3_recalculate_crc(struct rte_mbuf *m)
 			       m->data_len, RTE_NET_CRC32_ETH);
 
 	/*
-	 * The hns3 driver requires that mbuf size must be at least 512B.
-	 * When CRC is stripped by hardware, the pkt_len must be less than
-	 * or equal to 60B. Therefore, the space of the mbuf is enough
-	 * to insert the CRC.
-	 *
-	 * In addition, after CRC is stripped by hardware, pkt_len and data_len
-	 * do not contain the CRC length. Therefore, after CRC data is appended
-	 * by PMD again, both pkt_len and data_len add the CRC length.
+	 * After CRC is stripped by hardware, pkt_len and data_len do not contain the CRC length.
+	 * Therefore, after CRC data is appended by PMD again.
 	 */
 	append_data = rte_pktmbuf_append(m, RTE_NET_CRC32_ETH);
-	/* The CRC data is binary data and does not care about the byte order. */
-	rte_memcpy(append_data, (void *)&crc, RTE_NET_CRC32_ETH);
+
+	/* CRC data is binary data and does not care about the byte order. */
+	memcpy(append_data, &crc, RTE_NET_CRC32_ETH);
 }
 
 uint16_t
-- 
2.45.2