[dpdk-dev] [PATCH 2/3] [PMD] [VHOST] Support zero copy RX/TX in user space vhost

[Ouyang Changchun <changchun.ouyang@intel.com>]

Implement mbuf metadata macros to facilitate refering to space in mbuf headroom;

Signed-off-by: Ouyang Changchun <changchun.ouyang@intel.com>
---
 lib/librte_mbuf/rte_mbuf.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index edffc2c..baf3ca4 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -201,8 +201,25 @@ struct rte_mbuf {
 		struct rte_ctrlmbuf ctrl;
 		struct rte_pktmbuf pkt;
 	};
+
+	union {
+		uint8_t metadata[0];
+		uint16_t metadata16[0];
+		uint32_t metadata32[0];
+		uint64_t metadata64[0];
+	};
 } __rte_cache_aligned;
 
+#define RTE_MBUF_METADATA_UINT8(mbuf, offset)       (mbuf->metadata[offset])
+#define RTE_MBUF_METADATA_UINT16(mbuf, offset)      (mbuf->metadata16[offset/sizeof(uint16_t)])
+#define RTE_MBUF_METADATA_UINT32(mbuf, offset)      (mbuf->metadata32[offset/sizeof(uint32_t)])
+#define RTE_MBUF_METADATA_UINT64(mbuf, offset)      (mbuf->metadata64[offset/sizeof(uint64_t)])
+
+#define RTE_MBUF_METADATA_UINT8_PTR(mbuf, offset)   (&mbuf->metadata[offset])
+#define RTE_MBUF_METADATA_UINT16_PTR(mbuf, offset)  (&mbuf->metadata16[offset/sizeof(uint16_t)])
+#define RTE_MBUF_METADATA_UINT32_PTR(mbuf, offset)  (&mbuf->metadata32[offset/sizeof(uint32_t)])
+#define RTE_MBUF_METADATA_UINT64_PTR(mbuf, offset)  (&mbuf->metadata64[offset/sizeof(uint64_t)])
+
 /**
  * Given the buf_addr returns the pointer to corresponding mbuf.
  */
-- 
1.9.0