From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Xu Subject: Re: [PATCH v3 08/10] migration: handle the error condition properly Date: Wed, 8 Aug 2018 14:56:19 +0800 Message-ID: <20180808065619.GK24415@xz-mi> References: <20180807091209.13531-1-xiaoguangrong@tencent.com> <20180807091209.13531-9-xiaoguangrong@tencent.com> <20180808050846.GG24415@xz-mi> <503d7733-e2e7-09c5-75a3-1e250f549065@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: kvm@vger.kernel.org, mst@redhat.com, mtosatti@redhat.com, Xiao Guangrong , dgilbert@redhat.com, qemu-devel@nongnu.org, wei.w.wang@intel.com, jiang.biao2@zte.com.cn, pbonzini@redhat.com To: Xiao Guangrong Return-path: Content-Disposition: inline In-Reply-To: <503d7733-e2e7-09c5-75a3-1e250f549065@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel2=m.gmane.org@nongnu.org Sender: "Qemu-devel" List-Id: kvm.vger.kernel.org On Wed, Aug 08, 2018 at 02:29:52PM +0800, Xiao Guangrong wrote: > > > On 08/08/2018 01:08 PM, Peter Xu wrote: > > On Tue, Aug 07, 2018 at 05:12:07PM +0800, guangrong.xiao@gmail.com wrote: > > > From: Xiao Guangrong > > > > > > ram_find_and_save_block() can return negative if any error hanppens, > > > however, it is completely ignored in current code > > > > Could you hint me where we'll return an error? > > > > I think control_save_page() may return a error condition but i am not > good at it ... Other places look safe _currently_. These functions were > designed to have error returned anyway. Ah, the RDMA codes... Then I feel like this patch would be more suitable to be put into some of the RDMA series - at least we'd better be clear about what errors we're going to capture. For non-RDMA, it seems a bit helpless after all - AFAIU we're depending on the few qemu_file_get_error() calls to detect output errors. > > > (Anyway I agree that the error handling is not that good, mostly > > because the QEMUFile APIs does not provide proper return code, e.g., > > qemu_put_be64 returns void) > > > > Yes, it is, the returned error condition is mixed in file's API and > function's return value... :( > Regards, -- Peter Xu