[dpdk-dev,v4,7/9] librte_mbuf: Add rte_pktmbuf_mtod_offset()
Commit Message
There are a number of instances in the code where rte_pktmbuf_mtod()
is used to get the mbuf data pointer, only to add an offset before
casting the result to some other header type. This patch adds a new
rte_pktmbuf_mtod_offset() macro to eliminate these awful double cast
situations.
Change-Id: I4dec35a15e44a7b8c767559a8d3b294177f39552
Signed-off-by: Cyril Chemparathy <cchemparathy@ezchip.com>
---
lib/librte_mbuf/rte_mbuf.h | 24 +++++++++++++++++++++---
1 file changed, 21 insertions(+), 3 deletions(-)
@@ -54,6 +54,7 @@
*/
#include <stdint.h>
+#include <rte_common.h>
#include <rte_mempool.h>
#include <rte_memory.h>
#include <rte_atomic.h>
@@ -1080,18 +1081,35 @@ static inline struct rte_mbuf *rte_pktmbuf_lastseg(struct rte_mbuf *m)
}
/**
+ * A macro that points to an offset into the data in the mbuf.
+ *
+ * The returned pointer is cast to type t. Before using this
+ * function, the user must ensure that the first segment is large
+ * enough to accomodate its data.
+ *
+ * @param m
+ * The packet mbuf.
+ * @param o
+ * The offset into the mbuf data.
+ * @param t
+ * The type to cast the result into.
+ */
+#define rte_pktmbuf_mtod_offset(m, t, o) \
+ ((t)((char *)(m)->buf_addr + (m)->data_off + (o)))
+
+/**
* A macro that points to the start of the data in the mbuf.
*
* The returned pointer is cast to type t. Before using this
- * function, the user must ensure that m_headlen(m) is large enough to
- * read its data.
+ * function, the user must ensure that the first segment is large
+ * enough to accomodate its data.
*
* @param m
* The packet mbuf.
* @param t
* The type to cast the result into.
*/
-#define rte_pktmbuf_mtod(m, t) ((t)((char *)(m)->buf_addr + (m)->data_off))
+#define rte_pktmbuf_mtod(m, t) rte_pktmbuf_mtod_offset(m, t, 0)
/**
* A macro that returns the length of the packet.