net/fm10k: add compile-time checks to vector driver

The vector PMD is very sensitive to the layout of the mbuf, especially on
the RX path. Add in some compile-time checks to make sure the mbuf layout
assumptions are valid, and to provide hints to anyone changing the mbuf
where things may need to be updated.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>

diff --git a/drivers/net/fm10k/fm10k_rxtx_vec.c b/drivers/net/fm10k/fm10k_rxtx_vec.c
index 03f6fd7..d23bfe9 100644 (file)
--- a/drivers/net/fm10k/fm10k_rxtx_vec.c
+++ b/drivers/net/fm10k/fm10k_rxtx_vec.c
@@ -331,6 +331,8 @@ fm10k_rxq_rearm(struct fm10k_rx_queue *rxq)
                *(uint64_t *)p1 = rxq->mbuf_initializer;
 
                /* load buf_addr(lo 64bit) and buf_physaddr(hi 64bit) */
+               RTE_BUILD_BUG_ON(offsetof(struct rte_mbuf, buf_physaddr) !=
+                               offsetof(struct rte_mbuf, buf_addr) + 8);
                vaddr0 = _mm_loadu_si128((__m128i *)&mb0->buf_addr);
                vaddr1 = _mm_loadu_si128((__m128i *)&mb1->buf_addr);
 
@@ -448,6 +450,19 @@ fm10k_recv_raw_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
                0xFF, 0xFF,  /* skip high 16 bits pkt_type */
                0xFF, 0xFF   /* Skip pkt_type field in shuffle operation */
                );
+       /*
+        * Compile-time verify the shuffle mask
+        * NOTE: some field positions already verified above, but duplicated
+        * here for completeness in case of future modifications.
+        */
+       RTE_BUILD_BUG_ON(offsetof(struct rte_mbuf, pkt_len) !=
+                       offsetof(struct rte_mbuf, rx_descriptor_fields1) + 4);
+       RTE_BUILD_BUG_ON(offsetof(struct rte_mbuf, data_len) !=
+                       offsetof(struct rte_mbuf, rx_descriptor_fields1) + 8);
+       RTE_BUILD_BUG_ON(offsetof(struct rte_mbuf, vlan_tci) !=
+                       offsetof(struct rte_mbuf, rx_descriptor_fields1) + 10);
+       RTE_BUILD_BUG_ON(offsetof(struct rte_mbuf, hash) !=
+                       offsetof(struct rte_mbuf, rx_descriptor_fields1) + 12);
 
        /* Cache is empty -> need to scan the buffer rings, but first move
         * the next 'n' mbufs into the cache