From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31AA4C4727C for ; Wed, 30 Sep 2020 02:49:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E43B620936 for ; Wed, 30 Sep 2020 02:49:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729779AbgI3Ctf (ORCPT ); Tue, 29 Sep 2020 22:49:35 -0400 Received: from mga04.intel.com ([192.55.52.120]:42724 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729446AbgI3Ctf (ORCPT ); Tue, 29 Sep 2020 22:49:35 -0400 IronPort-SDR: ndhiDGJTxZjxf4YdrsuPqv3CMEiwp2zgXnhpqK2scDHO1OX6tdrhWhnfgm4eNbbfySjsxnCfbo 29OnTjhKI7MA== X-IronPort-AV: E=McAfee;i="6000,8403,9759"; a="159728460" X-IronPort-AV: E=Sophos;i="5.77,320,1596524400"; d="scan'208";a="159728460" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Sep 2020 19:49:33 -0700 IronPort-SDR: spis1oSx1F7YFD3eIP15/vaNC0KRWPa8nEFs1uHkZCRixULSY5PPiAA3Yb/Xti72dfEKZahoCz uYH63akBls9w== X-IronPort-AV: E=Sophos;i="5.77,320,1596524400"; d="scan'208";a="494945791" Received: from shuo-intel.sh.intel.com (HELO localhost) ([10.239.154.30]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Sep 2020 19:49:29 -0700 Date: Wed, 30 Sep 2020 10:49:27 +0800 From: Shuo A Liu To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, x86@kernel.org, "H . Peter Anvin" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Sean Christopherson , Yu Wang , Reinette Chatre , Zhi Wang , Zhenyu Wang Subject: Re: [PATCH v4 06/17] virt: acrn: Introduce VM management interfaces Message-ID: <20200930024927.GH1057@shuo-intel.sh.intel.com> References: <20200922114311.38804-1-shuo.a.liu@intel.com> <20200922114311.38804-7-shuo.a.liu@intel.com> <20200927104702.GE88650@kroah.com> <20200928035030.GD1057@shuo-intel.sh.intel.com> <20200928052516.GD767987@kroah.com> <20200928062934.GF1057@shuo-intel.sh.intel.com> <20200928122602.GB682772@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20200928122602.GB682772@kroah.com> User-Agent: Mutt/1.8.3 (2017-05-23) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 28.Sep'20 at 14:26:02 +0200, Greg Kroah-Hartman wrote: >On Mon, Sep 28, 2020 at 02:29:34PM +0800, Shuo A Liu wrote: >> On Mon 28.Sep'20 at 7:25:16 +0200, Greg Kroah-Hartman wrote: >> > On Mon, Sep 28, 2020 at 11:50:30AM +0800, Shuo A Liu wrote: >> > > > > + write_lock_bh(&acrn_vm_list_lock); >> > > > > + list_add(&vm->list, &acrn_vm_list); >> > > > > + write_unlock_bh(&acrn_vm_list_lock); >> > > > >> > > > Why are the _bh() variants being used here? >> > > > >> > > > You are only accessing this list from userspace context in this patch. >> > > > >> > > > Heck, you aren't even reading from the list, only writing to it... >> > > >> > > acrn_vm_list is read in a tasklet which dispatch I/O requests and is wrote >> > > in VM creation ioctl. Use the rwlock mechanism to protect it. >> > > The reading operation is introduced in the following patches of this >> > > series. So i keep the lock type at the moment of introduction. >> > >> > Ok, but think about someone trying to review this code. Does this lock >> > actually make sense here? No, it does not. How am I supposed to know >> > to look at future patches to determine that it changes location and >> > usage to require this? >> >> OK. May i know how to handle such kind of code submission? Or which way >> following do you prefer? >> 1) Use a mutex lock here, then change it to rwlock in a later patch >> of this series. > >Wouldn't this make more sense if you had to read these one after >another? OK. I will change to mutex firstly for more readable. > >> 2) Add more comments in changelog about the lock. (Now, there is >> comment around the acrn_vm_list_lock) > >It's hard to verify a comment's statement without digging through other >patches in the series, right? You want the reviewer to just trust you? >:) > >Again, what would _YOU_ want to see if you had to review this? > >> > That's just not fair, would you want to review something like this? >> > >> > And a HUGE meta-comment, again, why am I the only one reviewing this >> > stuff? Why do you have a ton of Intel people on the Cc: yet it is, once >> > again, my job to do this? >> >> The patchset has been reviewed in Intel's internal mailist several >> rounds and got Reviewed-by: before send out. That's why i Cced many >> Intel people as well. > >Then why didn't any of those intel people on the cc: actually review it >after you have sent it out? Why is it only me? Do I need to wait >longer for them to get to this? I'll gladly do so next time... > >> This patchset is all about a common driver for the ACRN hypervisor >> support. I put the code in drivers/virt/ and found you are one of the >> maintainer of vboxguest driver which is in the same subdirectory. I >> thought you should be the right person to be Cced when i submitted this >> series. > >I am, I'm not complaining about that. I'm complaining that it seems to >be _only_ me reviewing this here, and not any of the people you are cc:ing >from intel. Most of those people should be giving you this same type of >review comments and not forcing an external person to do so, right? > >> Certainly, any comments are welcome. And really appreciate your review >> and help. I have little experience to submit a new driver to the >> community, my apologies if thing goes wrong. > >You didn't do anything wrong, I'm arguing about the larger meta-issue I >have right now with Intel and the lack of reviews that seems to happen >from other Intel people on their co-workers patches. > >Anyway, you are doing fine, it's an iterative process, hopefully you can >also review other people's patches in this area that are being posted as >well. Sorry, i have no answer about some of your question above. :( However, i will try my best to help review other people's patches in this area. Thanks shuo