[dpdk-dev] [PATCH v4 1/2] mbuf: add function returning default buffer address
David Marchand
david.marchand at redhat.com
Fri Jan 11 09:11:39 CET 2019
On Thu, Jan 10, 2019 at 11:40 PM Yongseok Koh <yskoh at mellanox.com> wrote:
> This patch introduces two new functions - rte_mbuf_buf_addr() and
> rte_mbuf_data_addr_default().
>
> rte_mbuf_buf_addr() reutrns the default buffer address of given mbuf which
>
returns
> comes after mbuf structure and private data.
>
> rte_mbuf_data_addr_default() returns the default address of mbuf data
> taking the headroom into account.
>
> Signed-off-by: Yongseok Koh <yskoh at mellanox.com>
> ---
>
> Please ignore v3, there were errors with some compilers.
>
> v4:
> * fix compilation error due to the experimental tag
> * add warning of experimental tag to the comments
>
> v3:
> * rename functions
>
> v2:
> * initial implementation
>
> lib/librte_mbuf/rte_mbuf.h | 46
> ++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 46 insertions(+)
>
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> index bc562dc8a9..5787616999 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -788,8 +788,54 @@ rte_mbuf_from_indirect(struct rte_mbuf *mi)
> }
>
> /**
> + * Return the default buffer address of the mbuf.
>
Nit: missed it... s/default //
+ *
> + * @warning
> + * @b EXPERIMENTAL: This API may change without prior notice.
> + * This will be used by rte_mbuf_to_baddr() which has redundant code once
> + * experimental tag is removed.
>
Good point.
I wonder if we have a "todolist" for release n+2 so that we don't forget
about such things to do.
Thomas ?
+ *
> + * @param mb
> + * The pointer to the mbuf.
> + * @param mp
> + * The pointer to the mempool of the mbuf.
> + * @return
> + * The pointer of the mbuf buffer.
> + */
> +static inline char * __rte_experimental
> +rte_mbuf_buf_addr(struct rte_mbuf *mb, struct rte_mempool *mp)
> +{
> + char *buffer_addr;
> +
> + buffer_addr = (char *)mb + sizeof(*mb) + rte_pktmbuf_priv_size(mp);
> + return buffer_addr;
> +}
>
Nit:
+ return (char *)mb + sizeof(*mb) + rte_pktmbuf_priv_size(mp);
+
> +/**
> + * Return the default address of the beginning of the mbuf data.
> + *
> + * @warning
> + * @b EXPERIMENTAL: This API may change without prior notice.
> + *
> + * @param mb
> + * The pointer to the mbuf.
> + * @return
> + * The pointer of the beginning of the mbuf data.
> + */
> +static inline char * __rte_experimental
> +rte_mbuf_data_addr_default(struct rte_mbuf *mb)
> +{
> + return rte_mbuf_buf_addr(mb, mb->pool) + RTE_PKTMBUF_HEADROOM;
> +}
> +
> +/**
> * Return the buffer address embedded in the given mbuf.
> *
> + * @note: Accessing mempool pointer of a mbuf is expensive because the
> + * pointer is stored in the 2nd cache line of mbuf. If mempool is known,
> it
> + * is better not to reference the mempool pointer in mbuf but calling
> + * rte_mbuf_buf_addr() would be more efficient.
> + *
> * @param md
> * The pointer to the mbuf.
> * @return
> --
> 2.11.0
>
>
Thanks Yongseok.
Reviewed-by: David Marchand <david.marchand at redhat.com>
--
David Marchand
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