From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yuanhan Liu Subject: [PATCH 14/16] vhost: reserve few more space for future extension Date: Mon, 2 May 2016 15:25:25 -0700 Message-ID: <1462227927-22853-15-git-send-email-yuanhan.liu@linux.intel.com> References: <1462227927-22853-1-git-send-email-yuanhan.liu@linux.intel.com> Cc: huawei.xie@intel.com, Thomas Monjalon , Panu Matilainen , Tetsuya Mukawa , Traynor Kevin , Yuanhan Liu To: dev@dpdk.org Return-path: Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by dpdk.org (Postfix) with ESMTP id A35DE595C for ; Tue, 3 May 2016 00:22:41 +0200 (CEST) In-Reply-To: <1462227927-22853-1-git-send-email-yuanhan.liu@linux.intel.com> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" "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 388621e..4e50425 100644 --- a/lib/librte_vhost/rte_virtio_net.h +++ b/lib/librte_vhost/rte_virtio_net.h @@ -77,6 +77,8 @@ 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