Hi Bruce,
On 09/03/2014 05:49 PM, Bruce Richardson wrote:
> Removed the explicit zero-sized metadata definition at the end of the
> mbuf data structure. Updated the metadata macros to take account of this
> change so that all existing code which uses those macros still works.
>
> Signed-off-by: Bruce Richardson <bruce.richardson at intel.com>
> ---
> lib/librte_mbuf/rte_mbuf.h | 22 ++++++++--------------
> 1 file changed, 8 insertions(+), 14 deletions(-)
>
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> index 5260001..ca66d9a 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -166,31 +166,25 @@ struct rte_mbuf {
> struct rte_mempool *pool; /**< Pool from which mbuf was allocated. */
> struct rte_mbuf *next; /**< Next segment of scattered packet. */
>
> - union {
> - uint8_t metadata[0];
> - uint16_t metadata16[0];
> - uint32_t metadata32[0];
> - uint64_t metadata64[0];
> - } __rte_cache_aligned;
> } __rte_cache_aligned;
>
> #define RTE_MBUF_METADATA_UINT8(mbuf, offset) \
> - (mbuf->metadata[offset])
> + (((uint8_t *)&(mbuf)[1])[offset])
> #define RTE_MBUF_METADATA_UINT16(mbuf, offset) \
> - (mbuf->metadata16[offset/sizeof(uint16_t)])
> + (((uint16_t *)&(mbuf)[1])[offset/sizeof(uint16_t)])
> #define RTE_MBUF_METADATA_UINT32(mbuf, offset) \
> - (mbuf->metadata32[offset/sizeof(uint32_t)])
> + (((uint32_t *)&(mbuf)[1])[offset/sizeof(uint32_t)])
> #define RTE_MBUF_METADATA_UINT64(mbuf, offset) \
> - (mbuf->metadata64[offset/sizeof(uint64_t)])
> + (((uint64_t *)&(mbuf)[1])[offset/sizeof(uint64_t)])
>
> #define RTE_MBUF_METADATA_UINT8_PTR(mbuf, offset) \
> - (&mbuf->metadata[offset])
> + (&RTE_MBUF_METADATA_UINT8(mbuf, offset))
> #define RTE_MBUF_METADATA_UINT16_PTR(mbuf, offset) \
> - (&mbuf->metadata16[offset/sizeof(uint16_t)])
> + (&RTE_MBUF_METADATA_UINT16(mbuf, offset))
> #define RTE_MBUF_METADATA_UINT32_PTR(mbuf, offset) \
> - (&mbuf->metadata32[offset/sizeof(uint32_t)])
> + (&RTE_MBUF_METADATA_UINT32(mbuf, offset))
> #define RTE_MBUF_METADATA_UINT64_PTR(mbuf, offset) \
> - (&mbuf->metadata64[offset/sizeof(uint64_t)])
> + (&RTE_MBUF_METADATA_UINT64(mbuf, offset))
>
> /**
> * Given the buf_addr returns the pointer to corresponding mbuf.
>
I think it goes in the good direction. So:
Acked-by: Olivier Matz <olivier.matz at 6wind.com>
Just one question: why not removing RTE_MBUF_METADATA*() macros?
I'd just provide one macro that gives a (void*) to the first byte
after the mbuf structure.
The format of the metadata is up to the application, that usually
casts (m + 1) into a private structure, making the macros not very
useful. I suggest to move these macros outside rte_mbuf.h, in the
application-specific or library-specific header, what do you think?
Regards,
Olivier
