From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zoltan Kiss Subject: Re: [Xen-devel] [PATCH v3] xen/grant-table: Avoid m2p_override during mapping Date: Thu, 23 Jan 2014 13:05:50 +0000 Message-ID: <52E113AE.5060405@citrix.com> References: <1390244288-3186-1-git-send-email-zoltan.kiss@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit To: Konrad Rzeszutek Wilk , , , , , , Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 20/01/14 21:22, Konrad Rzeszutek Wilk wrote: > Zoltan Kiss wrote: >> The grant mapping API does m2p_override unnecessarily: only gntdev >> needs it, >> for blkback and future netback patches it just cause a lock contention, >> as >> those pages never go to userspace. Therefore this series does the >> following: >> - the original functions were renamed to __gnttab_[un]map_refs, with a >> new >> parameter m2p_override >> - based on m2p_override either they follow the original behaviour, or >> just set >> the private flag and call set_phys_to_machine >> - gnttab_[un]map_refs are now a wrapper to call __gnttab_[un]map_refs >> with >> m2p_override false >> - a new function gnttab_[un]map_refs_userspace provides the old >> behaviour > > You don't say anything about the 'return ret' changed to 'return 0'. > > Any particular reason for that? That's the only possible return value there, so it just makes it more obvious. I'll add a description about that. Zoli