mbuf: use macros only to access metadata

Removed the explicit zero-sized metadata definition at the end of the
mbuf data structure. Updated the metadata macros to take account of this
change so that all existing code which uses those macros still works.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>

diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index 6ce852a..f855e64 100644 (file)
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -171,31 +171,25 @@ struct rte_mbuf {
        struct rte_mempool *pool; /**< Pool from which mbuf was allocated. */
        struct rte_mbuf *next;    /**< Next segment of scattered packet. */
 
-       union {
-               uint8_t metadata[0];
-               uint16_t metadata16[0];
-               uint32_t metadata32[0];
-               uint64_t metadata64[0];
-       } __rte_cache_aligned;
 } __rte_cache_aligned;
 
 #define RTE_MBUF_METADATA_UINT8(mbuf, offset)              \
-       (mbuf->metadata[offset])
+       (((uint8_t *)&(mbuf)[1])[offset])
 #define RTE_MBUF_METADATA_UINT16(mbuf, offset)             \
-       (mbuf->metadata16[offset/sizeof(uint16_t)])
+       (((uint16_t *)&(mbuf)[1])[offset/sizeof(uint16_t)])
 #define RTE_MBUF_METADATA_UINT32(mbuf, offset)             \
-       (mbuf->metadata32[offset/sizeof(uint32_t)])
+       (((uint32_t *)&(mbuf)[1])[offset/sizeof(uint32_t)])
 #define RTE_MBUF_METADATA_UINT64(mbuf, offset)             \
-       (mbuf->metadata64[offset/sizeof(uint64_t)])
+       (((uint64_t *)&(mbuf)[1])[offset/sizeof(uint64_t)])
 
 #define RTE_MBUF_METADATA_UINT8_PTR(mbuf, offset)          \
-       (&mbuf->metadata[offset])
+       (&RTE_MBUF_METADATA_UINT8(mbuf, offset))
 #define RTE_MBUF_METADATA_UINT16_PTR(mbuf, offset)         \
-       (&mbuf->metadata16[offset/sizeof(uint16_t)])
+       (&RTE_MBUF_METADATA_UINT16(mbuf, offset))
 #define RTE_MBUF_METADATA_UINT32_PTR(mbuf, offset)         \
-       (&mbuf->metadata32[offset/sizeof(uint32_t)])
+       (&RTE_MBUF_METADATA_UINT32(mbuf, offset))
 #define RTE_MBUF_METADATA_UINT64_PTR(mbuf, offset)         \
-       (&mbuf->metadata64[offset/sizeof(uint64_t)])
+       (&RTE_MBUF_METADATA_UINT64(mbuf, offset))
 
 /**
  * Given the buf_addr returns the pointer to corresponding mbuf.