From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ferruh Yigit Subject: Re: [PATCH v4] ethdev: return named opaque type instead of void pointer Date: Fri, 9 Mar 2018 13:00:35 +0000 Message-ID: References: <20180117215802.90809-2-ferruh.yigit@intel.com> <20180309112531.292163-1-ferruh.yigit@intel.com> <20180309123651.GB19004@hmswarspite.think-freely.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: John McNamara , Marko Kovacevic , Thomas Monjalon , dev@dpdk.org To: Neil Horman Return-path: Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by dpdk.org (Postfix) with ESMTP id 784435F13 for ; Fri, 9 Mar 2018 14:00:38 +0100 (CET) In-Reply-To: <20180309123651.GB19004@hmswarspite.think-freely.org> Content-Language: en-US List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On 3/9/2018 12:36 PM, Neil Horman wrote: > On Fri, Mar 09, 2018 at 11:25:31AM +0000, Ferruh Yigit wrote: >> "struct rte_eth_rxtx_callback" is defined as internal data structure and >> used as named opaque type. >> >> So the functions that are adding callbacks can return objects in this >> type instead of void pointer. >> >> Signed-off-by: Ferruh Yigit >> Acked-by: Stephen Hemminger >> --- >> v2: >> * keep using struct * in parameters, instead add callback functions >> return struct rte_eth_rxtx_callback pointer. >> >> v4: >> * Remove deprecation notice. LIBABIVER already increased in this release >> --- >> doc/guides/rel_notes/deprecation.rst | 7 ------- >> lib/librte_ether/rte_ethdev.c | 6 +++--- >> lib/librte_ether/rte_ethdev.h | 13 ++++++++----- >> 3 files changed, 11 insertions(+), 15 deletions(-) >> > This doesn't quite make sense to me. If rte_eth_rxtx_callback is defined as an > internal data structure, then it shouldn't be used as part of the prototype for > an exported function, as the structure will then no longer be a internal data > structure, but rather part of the public ABI. "struct rte_eth_rxtx_callback" is internal data structure. And application should not access elements of this structure. "struct rte_eth_rxtx_callback;" is defined in the public header, so applications can use it as opaque type. It is possible that both "add" and "remove" APIs use "void *" and API itself can cast it. But the inconsistency was "add" related APIs return "void *" and "remove" related APIs require a parameter in "struct rte_eth_rxtx_callback *" type. While unifying the usage, "struct rte_eth_rxtx_callback *" preferred against "void *", because named opaque type documents intention/usage better. Thanks, ferruh > > Neil >