Re: [Xen-devel] [PATCH v2 2/4] xen: introduce grant_map_exists

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Fri, 3 Oct 2014, Andrew Cooper wrote:
> On 03/10/14 15:50, Stefano Stabellini wrote:
> > Check whether an mfn has been granted to a given domain on a target
> > grant table.
> >
> > Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> >
> > ---
> >
> > Changes in v2:
> > - make the function static;
> > - remove the spin_lock.
> > ---
> >  xen/common/grant_table.c |   30 ++++++++++++++++++++++++++++++
> >  1 file changed, 30 insertions(+)
> >
> > diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
> > index 23266c3..7a6399b 100644
> > --- a/xen/common/grant_table.c
> > +++ b/xen/common/grant_table.c
> > @@ -484,6 +484,36 @@ static int _set_status(unsigned gt_version,
> >          return _set_status_v2(domid, readonly, mapflag, shah, act, status);
> >  }
> >  
> > +static bool_t grant_map_exists(struct domain *ld,
> > +                        struct grant_table *rgt,
> > +                        unsigned long mfn)
> > +{
> > +    struct active_grant_entry *act;
> > +    grant_ref_t ref;
> > +    bool_t ret = 0;
> > +
> > +    ASSERT(&rgt->lock);
> 
> I presume you mean spin_is_locked()?  This assertion is currently a
> tautology.

Ooops, you are right.


> ~Andrew
> 
> > +
> > +    for ( ref = 0; ref != nr_grant_entries(rgt); ref++ )
> > +    {
> > +        act = &active_entry(rgt, ref);
> > +
> > +        if ( !act->pin )
> > +            continue;
> > +
> > +        if ( act->domid != ld->domain_id )
> > +            continue;
> > +
> > +        if ( act->frame != mfn )
> > +            continue;
> > +        
> > +        ret = 1;
> > +        break;
> > +    }
> > +
> > +    return ret;
> > +}
> > +
> >  static void mapcount(
> >      struct grant_table *lgt, struct domain *rd, unsigned long mfn,
> >      unsigned int *wrc, unsigned int *rdc)
> 

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