[dpdk-dev] [PATCH v2 1/2] mbuf: add function returning default buffer address
Yongseok Koh
yskoh at mellanox.com
Wed Jan 9 14:19:07 CET 2019
This patch introduces two new functions - rte_mbuf_buf_addr_default() and
rte_mbuf_data_baddr_default().
rte_mbuf_buf_addr_default() reutrns the default buffer address of given
mbuf which comes after mbuf structure and private data.
rte_mbuf_data_baddr_default() returns the default address of mbuf data
taking the headroom into account.
Signed-off-by: Yongseok Koh <yskoh at mellanox.com>
---
v2:
* initial implementation
lib/librte_mbuf/rte_mbuf.h | 43 ++++++++++++++++++++++++++++++++++++++++---
1 file changed, 40 insertions(+), 3 deletions(-)
diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index bc562dc8a9..6c4c1bd3e8 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -788,8 +788,47 @@ rte_mbuf_from_indirect(struct rte_mbuf *mi)
}
/**
+ * Return the default buffer address of the mbuf.
+ *
+ * @param mb
+ * The pointer to the mbuf.
+ * @param mp
+ * The pointer to the mempool of the mbuf.
+ * @return
+ * The pointer of the mbuf buffer.
+ */
+static inline char *
+rte_mbuf_buf_addr_default(struct rte_mbuf *mb, struct rte_mempool *mp)
+{
+ char *buffer_addr;
+
+ buffer_addr = (char *)mb + sizeof(*mb) + rte_pktmbuf_priv_size(mp);
+ return buffer_addr;
+}
+
+
+/**
+ * Return the default address of the beginning of the mbuf data.
+ *
+ * @param mb
+ * The pointer to the mbuf.
+ * @return
+ * The pointer of the beginning of the mbuf data.
+ */
+static inline char *
+rte_mbuf_data_baddr_default(struct rte_mbuf *mb)
+{
+ return rte_mbuf_buf_addr_default(mb, mb->pool) + RTE_PKTMBUF_HEADROOM;
+}
+
+/**
* Return the buffer address embedded in the given mbuf.
*
+ * Note that accessing mempool pointer of a mbuf is expensive because the
+ * pointer is stored in the 2nd cache line of mbuf. If mempool is known, it
+ * is better not to reference the mempool pointer in mbuf but calling
+ * rte_mbuf_buf_addr_default() would be more efficient.
+ *
* @param md
* The pointer to the mbuf.
* @return
@@ -798,9 +837,7 @@ rte_mbuf_from_indirect(struct rte_mbuf *mi)
static inline char *
rte_mbuf_to_baddr(struct rte_mbuf *md)
{
- char *buffer_addr;
- buffer_addr = (char *)md + sizeof(*md) + rte_pktmbuf_priv_size(md->pool);
- return buffer_addr;
+ return rte_mbuf_buf_addr_default(md, md->pool);
}
/**
--
2.11.0
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