From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yongseok Koh Subject: [PATCH v5 1/2] mbuf: add function returning buffer address Date: Mon, 14 Jan 2019 13:16:21 -0800 Message-ID: <20190114211622.6900-1-yskoh@mellanox.com> References: <20190109085426.39965-1-yskoh@mellanox.com> Cc: dev@dpdk.org, arybchenko@solarflare.com, roszenrami@gmail.com, david.marchand@redhat.com To: olivier.matz@6wind.com, shahafs@mellanox.com Return-path: Received: from mellanox.co.il (mail-il-dmz.mellanox.com [193.47.165.129]) by dpdk.org (Postfix) with ESMTP id B1BE21B150 for ; Mon, 14 Jan 2019 22:16:30 +0100 (CET) In-Reply-To: <20190109085426.39965-1-yskoh@mellanox.com> List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" This patch introduces two new functions - rte_mbuf_buf_addr() and rte_mbuf_data_addr_default(). rte_mbuf_buf_addr() reutrns the buffer address of given mbuf which 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 Acked-by: Olivier Matz Reviewed-by: David Marchand --- v5: * add more comment regarding mp arg * use ALLOW_EXPERIMENTAL_API for rte_mbuf_to_baddr() 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 | 54 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 53 insertions(+), 1 deletion(-) diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h index bc562dc8a9..4a03d5e6fc 100644 --- a/lib/librte_mbuf/rte_mbuf.h +++ b/lib/librte_mbuf/rte_mbuf.h @@ -788,7 +788,55 @@ rte_mbuf_from_indirect(struct rte_mbuf *mi) } /** - * Return the buffer address embedded in the given mbuf. + * Return address of buffer embedded in the given mbuf. + * + * The return value shall be same as mb->buf_addr if the mbuf is already + * initialized and direct. However, this API is useful if mempool of the + * mbuf is already known because it doesn't need to access mbuf contents in + * order to get the mempool pointer. + * + * @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. + * + * @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) +{ + 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 address of buffer 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. @@ -798,9 +846,13 @@ rte_mbuf_from_indirect(struct rte_mbuf *mi) static inline char * rte_mbuf_to_baddr(struct rte_mbuf *md) { +#ifdef ALLOW_EXPERIMENTAL_API + return rte_mbuf_buf_addr(md, md->pool); +#else char *buffer_addr; buffer_addr = (char *)md + sizeof(*md) + rte_pktmbuf_priv_size(md->pool); return buffer_addr; +#endif } /** -- 2.11.0