From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by dpdk.org (Postfix) with ESMTP id 63A678E60 for ; Fri, 13 May 2016 07:20:34 +0200 (CEST) Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga101.fm.intel.com with ESMTP; 12 May 2016 22:20:35 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,612,1455004800"; d="scan'208";a="805315153" Received: from yliu-dev.sh.intel.com ([10.239.67.162]) by orsmga003.jf.intel.com with ESMTP; 12 May 2016 22:20:32 -0700 From: Yuanhan Liu To: dev@dpdk.org Cc: Thomas Monjalon , huawei.xie@intel.com, Panu Matilainen , Tetsuya Mukawa , Traynor Kevin , Rich Lane , Yuanhan Liu Date: Thu, 12 May 2016 22:25:09 -0700 Message-Id: <1463117111-27050-18-git-send-email-yuanhan.liu@linux.intel.com> X-Mailer: git-send-email 1.9.0 In-Reply-To: <1463117111-27050-1-git-send-email-yuanhan.liu@linux.intel.com> References: <1462227927-22853-1-git-send-email-yuanhan.liu@linux.intel.com> <1463117111-27050-1-git-send-email-yuanhan.liu@linux.intel.com> Subject: [dpdk-dev] [PATCH v2 17/19] vhost: reserve few more space for future extension X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 13 May 2016 05:20:35 -0000 "virtio_net_device_ops" is the only left open struct that an application can access, therefore, it's the only place that might introduce potential ABI break in future for extension. So, do some reservation for it. 5 should be pretty enough, considering that we have barely touched it for a long while. Another reason to choose 5 is for cache alignment: 5 makes the struct 64 bytes for 64 bit machine. With this, it's confidence to say that we might be able to be free from the ABI violation forever. Signed-off-by: Yuanhan Liu --- lib/librte_vhost/rte_virtio_net.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/lib/librte_vhost/rte_virtio_net.h b/lib/librte_vhost/rte_virtio_net.h index fc1d799..bc2b74b 100644 --- a/lib/librte_vhost/rte_virtio_net.h +++ b/lib/librte_vhost/rte_virtio_net.h @@ -66,6 +66,8 @@ struct virtio_net_device_ops { void (*destroy_device)(int vid); /**< Remove device. */ int (*vring_state_changed)(int vid, uint16_t queue_id, int enable); /**< triggered when a vring is enabled or disabled */ + + void *reserved[5]; /**< Reserved for future extension */ }; /** -- 1.9.0