From mboxrd@z Thu Jan 1 00:00:00 1970 From: annie li Subject: Re: [Xen-devel] [PATCH net-next] xen-netfront: clean up code in xennet_release_rx_bufs Date: Wed, 15 Jan 2014 22:15:23 +0800 Message-ID: <52D697FB.3000304@oracle.com> References: <1389307718-2845-1-git-send-email-Annie.li@oracle.com> <20140115100743.GG5698@zion.uk.xensource.com> <52D66ADF.9070401@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Wei Liu , netdev@vger.kernel.org, ian.campbell@citrix.com, xen-devel@lists.xen.org To: Andrew Bennieston Return-path: Received: from userp1040.oracle.com ([156.151.31.81]:36008 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752089AbaAOOPh (ORCPT ); Wed, 15 Jan 2014 09:15:37 -0500 In-Reply-To: <52D66ADF.9070401@citrix.com> Sender: netdev-owner@vger.kernel.org List-ID: On 2014-1-15 19:02, Andrew Bennieston wrote: > On 15/01/14 10:07, Wei Liu wrote: >> On Fri, Jan 10, 2014 at 06:48:38AM +0800, Annie Li wrote: >>> Current netfront only grants pages for grant copy, not for grant >>> transfer, so >>> remove corresponding transfer code and add receiving copy code in >>> xennet_release_rx_bufs. >>> >> >> This path seldom gets call -- not that many people unload xen-netfront >> driver. If Annie has tested this patch and it works as expected I think >> it's fine. >> > In XenServer we have seen a number of cases where unplugging and > replugging VIFs results in leakage of grant references, eventually > leading to a case where you cannot plug a VIF (after ~ 400 such > cycles)... > > It's worth pointing out, as far as this patch is concerned, that > gnttab_end_foreign_access() can fail, Just like what Wei mentioned, it is gnttab_end_foreign_access_ref here, right? > which is not taken into account here. Good point, gnttab_end_foreign_access_ref fails for grant which is in use. Thanks Annie > > Andrew. > >> I'm not netfront maintainer but I'm happy to add >> Acked-by: Wei Liu >> if Annie confirms she's tested this patch. >> >> Wei. >> >> _______________________________________________ >> Xen-devel mailing list >> Xen-devel@lists.xen.org >> http://lists.xen.org/xen-devel >> >