[dpdk-dev] [PATCH V2 2/3] mbuf: avoid cast-align warning in pktmbuf mtod offset macro
Eli Britstein
elibr at nvidia.com
Thu Oct 21 10:51:31 CEST 2021
In rte_pktmbuf_mtod_offset macro, there is a casting from char * to type
't', which may cause cast-align warning when using strict cast align
flag with supporting gcc:
gcc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0
CFLAGS="-Wcast-align=strict" make V=1 -C examples/l2fwd clean static
main.c: In function 'l2fwd_mac_updating':
/dpdk/build/include/rte_mbuf_core.h:719:3: warning: cast increases
required alignment of target type [-Wcast-align]
719 | ((t)((char *)(m)->buf_addr + (m)->data_off + (o)))
| ^
/dpdk/build/include/rte_mbuf_core.h:733:32: note: in expansion of macro
'rte_pktmbuf_mtod_offset'
733 | #define rte_pktmbuf_mtod(m, t) rte_pktmbuf_mtod_offset(m, t, 0)
| ^~~~~~~~~~~~~~~~~~~~~~~
As the code assumes correct alignment, add first a (void *) casting, to
avoid the warning.
Fixes: af75078fece3 ("first public release")
Cc: stable at dpdk.org
Signed-off-by: Eli Britstein <elibr at nvidia.com>
Acked-by: Olivier Matz <olivier.matz at 6wind.com>
---
lib/mbuf/rte_mbuf_core.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/mbuf/rte_mbuf_core.h b/lib/mbuf/rte_mbuf_core.h
index fdaaaf67f2..dd08d42aca 100644
--- a/lib/mbuf/rte_mbuf_core.h
+++ b/lib/mbuf/rte_mbuf_core.h
@@ -716,7 +716,7 @@ struct rte_mbuf_ext_shared_info {
* The type to cast the result into.
*/
#define rte_pktmbuf_mtod_offset(m, t, o) \
- ((t)((char *)(m)->buf_addr + (m)->data_off + (o)))
+ ((t)(void *)((char *)(m)->buf_addr + (m)->data_off + (o)))
/**
* A macro that points to the start of the data in the mbuf.
--
2.28.0.2311.g225365fb51
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