From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [PATCHv11 2/4] gnttab: introduce maptrack lock Date: Fri, 5 Jun 2015 14:44:16 +0100 Message-ID: <5571A7B0.3090305@citrix.com> References: <1433262381-8965-1-git-send-email-david.vrabel@citrix.com> <1433262381-8965-3-git-send-email-david.vrabel@citrix.com> <5571C1D6020000780008168A@mail.emea.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1Z0rvd-0002rX-TE for xen-devel@lists.xenproject.org; Fri, 05 Jun 2015 13:44:57 +0000 In-Reply-To: <5571C1D6020000780008168A@mail.emea.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: xen-devel@lists.xenproject.org, Malcolm Crossley , Keir Fraser , Ian Campbell , Tim Deegan List-Id: xen-devel@lists.xenproject.org On 05/06/15 14:35, Jan Beulich wrote: >>>> On 02.06.15 at 18:26, wrote: >> --- a/xen/common/grant_table.c >> +++ b/xen/common/grant_table.c >> @@ -288,10 +288,10 @@ static inline void put_maptrack_handle( >> struct grant_table *t, int handle) >> { >> - spin_lock(&t->lock); >> + spin_lock(&t->maptrack_lock); >> maptrack_entry(t, handle).ref = t->maptrack_head; >> t->maptrack_head = handle; >> - spin_unlock(&t->lock); >> + spin_unlock(&t->maptrack_lock); > > Starting with this change it becomes unclear what protects the > maptrack entries - the grant table lock or the maptrack one? The grant table lock. The docs aren't very good here -- the maptrack lock is only for the maptrack free list. David