[dpdk-dev] [PATCH v4 2/9] mbuf: silence -Wcast-align on pointer arithmetic

[Cyril Chemparathy <cchemparathy@ezchip.com>]

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 *).

Change-Id: I60d9b7a9205ff0befb8dbb4cdcb1df6f9d9d0250
Signed-off-by: Cyril Chemparathy <cchemparathy@ezchip.com>
---
 lib/librte_mbuf/rte_mbuf.h | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index 6c9cfd6..6efd2b5 100644
--- 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);
 }
 
 /**
-- 
2.1.2