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From: Cyril Chemparathy <cchemparathy@ezchip.com>
To: dev@dpdk.org
Subject: [dpdk-dev] [PATCH v2 02/10] mbuf: silence -Wcast-align on pointer arithmetic
Date: Fri, 19 Jun 2015 10:34:45 -0700	[thread overview]
Message-ID: <1434735293-15469-3-git-send-email-cchemparathy@ezchip.com> (raw)
In-Reply-To: <1434735293-15469-1-git-send-email-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 *).

Acked-by: Olivier Matz <olivier.matz@6wind.com>
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

  parent reply	other threads:[~2015-06-19 17:35 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-19 17:34 [dpdk-dev] [PATCH v2 00/10] Improve cast alignment for strict aligned machines Cyril Chemparathy
2015-06-19 17:34 ` [dpdk-dev] [PATCH v2 01/10] mempool: silence -Wcast-align on pointer arithmetic Cyril Chemparathy
2015-06-19 17:34 ` Cyril Chemparathy [this message]
2015-06-19 17:34 ` [dpdk-dev] [PATCH v2 03/10] ethdev: " Cyril Chemparathy
2015-06-19 17:34 ` [dpdk-dev] [PATCH v2 04/10] hash: " Cyril Chemparathy
2015-06-19 17:34 ` [dpdk-dev] [PATCH v2 05/10] eal: add and use unaligned integer types Cyril Chemparathy
2015-06-22  9:36   ` Thomas Monjalon
2015-06-22 16:47     ` Cyril Chemparathy
2015-06-22 16:56       ` Thomas Monjalon
2015-06-19 17:34 ` [dpdk-dev] [PATCH v2 06/10] app/test-pmd: pack simple_gre_hdr Cyril Chemparathy
2015-06-19 17:34 ` [dpdk-dev] [PATCH v2 07/10] app/test: use struct ether_addr instead of a byte array cast Cyril Chemparathy
2015-06-22  1:56   ` Stephen Hemminger
2015-06-22 16:40     ` Cyril Chemparathy
2015-06-19 17:34 ` [dpdk-dev] [PATCH v2 08/10] librte_mbuf: Add rte_pktmbuf_mtod_offset() Cyril Chemparathy
2015-06-19 17:34 ` [dpdk-dev] [PATCH v2 09/10] librte_mbuf: Add transform for rte_pktmbuf_mtod_offset() Cyril Chemparathy
2015-06-19 17:34 ` [dpdk-dev] [PATCH v2 10/10] librte_mbuf: Apply mtod-offset.cocci transform Cyril Chemparathy

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