From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Coquelin Subject: Re: [PATCH v2 01/10] lib/librte_vhost: add vhost user private info structure Date: Wed, 21 Mar 2018 14:02:35 +0100 Message-ID: <87a9b225-dfa0-adbd-5a5e-483a1dcd0027@redhat.com> References: <20180227162917.35125-1-roy.fan.zhang@intel.com> <20180227162917.35125-2-roy.fan.zhang@intel.com> <0f21227c-5b5f-a3f7-707a-60476826158e@redhat.com> <9F7182E3F746AB4EA17801C148F3C60433102660@IRSMSX101.ger.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: "jianjay.zhou@huawei.com" , "yliu@fridaylinux.org" , "Tan, Jianfeng" , "Bie, Tiwei" To: "Zhang, Roy Fan" , "dev@dpdk.org" , "Kulasek, TomaszX" , "Wodkowski, PawelX" Return-path: Received: from mx1.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by dpdk.org (Postfix) with ESMTP id 8C4CE4F9A for ; Wed, 21 Mar 2018 14:02:39 +0100 (CET) In-Reply-To: <9F7182E3F746AB4EA17801C148F3C60433102660@IRSMSX101.ger.corp.intel.com> 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" Hi, On 03/21/2018 10:10 AM, Zhang, Roy Fan wrote: > Hi Maxime, > > Thanks for the review. > >> >> I think this include isn't needed looking at the rest of the patch. > > I agree. I will remove this line here. > >>> #define VHOST_USER_VERSION 0x1 >>> >>> +typedef int (*msg_handler)(struct virtio_net *dev, struct VhostUserMsg >> *msg, >>> + int fd); >>> + >>> +struct vhost_user_dev_priv { >>> + msg_handler vhost_user_msg_handler; >>> + char data[0]; >>> +}; >>> >>> /* vhost_user.c */ >>> int vhost_user_msg_handler(int vid, int fd); >>> >> >> I think the wording is a bit misleading, I'm fine with having a private_data >> pointer, but it should only be used by the external backend. >> >> Maybe what you need here is a new API to be to register a callback for the >> external backend to handle specific requests. > > That's exactly what I need. > Shall I rework the code like this? These new API are to be placed in rte_vhost.h, else it won't be exported. > /* vhost.h */ > struct virtio_net { > .... > void *extern_data; /*<< private data for external backend */ > > } Looks good, you may need to add getter and setter APIs as struct virtio_net isn't part of the API. > /* vhost_user.h */ > typedef int (*msg_handler)(struct virtio_net *dev, struct VhostUserMsg *msg, > int fd); I wonder if the fd is really necessary, as if a reply is to be sent, it can be done by the vhost lib. > struct vhost_user_dev_extern { > msg_handler post_vhost_user_msg_handler; > char data[0]; Why is this filed needed? > }; I would change this to: struct rte_vhost_user_dev_extern_ops { rte_vhost_msg_handler pre_vhost_user_msg_handler; rte_vhost_msg_handler post_vhost_user_msg_handler; }; > int > vhost_user_register_call_back(struct virtio_net *dev, msg_handler post_msg_handler); and something like: rte_vhost_user_register_extern_ops(struct virtio_net *dev, struct rte_vhost_user_dev_extern_ops *ops); >> >> Also, it might be interesting for the external backend to register callbacks for >> existing requests. For example .pre_vhost_user_msg_handler >> and .post_vhost_user_msg_handler. Doing so, the external backend could >> for example catch beforehand any change that could affect resources being >> used. Tomasz, Pawel, do you think that could help for the issue you reported? >> > > > I think it is definitely a good idea. However there will be a problem. As vhost_crypto does not require pre_vhost_user_msg_handler I think it may not appropriate to add pre_vhost_user_msg_handler in this patchset. I see, but please add the pre_ callback directly in this series, as we know it will be useful (thanks Pawel). It will avoid breaking the API again when we'll need it. Thanks, Maxime > Thanks a million Maxime. > >> Thanks, >> Maxime