Re: [PATCH] xen/gnttab: leave lazy MMU mode in the case of a m2p override failure

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Fri, Nov 29, 2013 at 12:22:40PM +0000, Stefano Stabellini wrote:
> On Fri, 22 Nov 2013, Konrad Rzeszutek Wilk wrote:
> > On Wed, Nov 20, 2013 at 12:11:35PM -0800, Matt Wilson wrote:
> > > From: Matt Wilson <msw@amazon.com>
> > > 
> > > Commit f62805f1 introduced a bug where lazy MMU mode isn't exited if a
> > > m2p_add/remove_override call fails.
> > 
> > Stefano?
> > 
> 
> Already acked here:
> 
> http://marc.info/?l=linux-kernel&m=138505917602905&w=2

Sent to Linus today.

Thank you!
> 
> 
> 
> > > Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > > Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> > > Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> > > Cc: David Vrabel <david.vrabel@citrix.com>
> > > Cc: Anthony Liguori <aliguori@amazon.com>
> > > Cc: xen-devel@lists.xenproject.org
> > > Cc: linux-kernel@vger.kernel.org
> > > Signed-off-by: Matt Wilson <msw@amazon.com>
> > > ---
> > >  drivers/xen/grant-table.c |    6 ++++--
> > >  1 file changed, 4 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
> > > index 62ccf54..0283871 100644
> > > --- a/drivers/xen/grant-table.c
> > > +++ b/drivers/xen/grant-table.c
> > > @@ -930,9 +930,10 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
> > >  		ret = m2p_add_override(mfn, pages[i], kmap_ops ?
> > >  				       &kmap_ops[i] : NULL);
> > >  		if (ret)
> > > -			return ret;
> > > +			goto out;
> > >  	}
> > >  
> > > + out:
> > >  	if (lazy)
> > >  		arch_leave_lazy_mmu_mode();
> > >  
> > > @@ -969,9 +970,10 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
> > >  		ret = m2p_remove_override(pages[i], kmap_ops ?
> > >  				       &kmap_ops[i] : NULL);
> > >  		if (ret)
> > > -			return ret;
> > > +			goto out;
> > >  	}
> > >  
> > > + out:
> > >  	if (lazy)
> > >  		arch_leave_lazy_mmu_mode();
> > >  
> > > -- 
> > > 1.7.9.5
> > > 
> >