mbuf: silence warning on pointer arithmetic

Translating from an mbuf element to the mbuf pointer does not break alignment
constraints.  However, the compiler is unaware of this fact and complains on
-Wcast-align.  This patch modifies the code to use RTE_PTR_SUB(), thereby
silencing the compiler by casting through (void *).

Signed-off-by: Cyril Chemparathy <cchemparathy@ezchip.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 eed481e..70da797 100644 (file)
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -347,13 +347,7 @@ static inline uint16_t rte_pktmbuf_priv_size(struct rte_mempool *mp);
 static inline struct rte_mbuf *
 rte_mbuf_from_indirect(struct rte_mbuf *mi)
 {
-       struct rte_mbuf *md;
-
-       /* mi->buf_addr and mi->priv_size correspond to buffer and
-        * private size of the direct mbuf */
-       md = (struct rte_mbuf *)((char *)mi->buf_addr - sizeof(*mi) -
-               mi->priv_size);
-       return md;
+       return RTE_PTR_SUB(mi->buf_addr, sizeof(*mi) + mi->priv_size);
 }
 
 /**