[dpdk-dev] [PATCH v9 01/25] eal: define macro container_of
Ferruh Yigit
ferruh.yigit at intel.com
Thu Sep 8 16:16:34 CEST 2016
On 9/7/2016 3:07 PM, Shreyansh Jain wrote:
> Signed-off-by: Jan Viktorin <viktorin at rehivetech.com>
> Signed-off-by: Shreyansh Jain <shreyansh.jain at nxp.com>
> ---
> lib/librte_eal/common/include/rte_common.h | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)
>
> diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
> index 332f2a4..c5d94f3 100644
> --- a/lib/librte_eal/common/include/rte_common.h
> +++ b/lib/librte_eal/common/include/rte_common.h
> @@ -322,6 +322,27 @@ rte_bsf32(uint32_t v)
> #define offsetof(TYPE, MEMBER) __builtin_offsetof (TYPE, MEMBER)
> #endif
>
> +/**
> + * Return pointer to the wrapping struct instance.
> + * Example:
> + *
> + * struct wrapper {
> + * ...
> + * struct child c;
> + * ...
> + * };
> + *
> + * struct child *x = obtain(...);
> + * struct wrapper *w = container_of(x, struct wrapper, c);
> + *
> + * Some implementation already have this defined, thus, conditional
> + * declaration.
> + */
> +#ifndef container_of
> +#define container_of(p, type, member) \
> + ((type *) (((char *) (p)) - offsetof(type, member)))
> +#endif
> +
> #define _RTE_STR(x) #x
> /** Take a macro value and get a string version of it */
> #define RTE_STR(x) _RTE_STR(x)
>
Some mlx5 files includes dpdk version of container_of first, they
produce following warning:
In file included from .../dpdk/build/include/rte_mbuf.h:57:0,
from .../dpdk/build/include/rte_ether.h:52,
from .../dpdk/drivers/net/mlx5/mlx5_trigger.c:38:
/usr/include/infiniband/verbs.h: In function ‘verbs_get_device’:
.../dpdk/build/include/rte_common.h:343:14: warning: cast discards
‘const’ qualifier from pointer target type [-Wcast-qual]
((type *) (((char *) (p)) - offsetof(type, member)))
The verbs.h version of container_of is same with dpdk one, I am not able
to find why one gives warning but other not.
Regards,
ferruh
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