Re: [Xen-devel] Re: [Xen-changelog] [xen-unstable] stubdom: mmap on /dev/mem support

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Wed, 21 Oct 2009, Samuel Thibault wrote:
> Xen patchbot-unstable, le Wed 21 Oct 2009 08:10:15 -0700, a écrit :
> > +        unsigned long mfns[n];
> > +        for (i = 0; i < n; i++)
> > +            mfns[i] = ((unsigned long) offset + (i * PAGE_SIZE)) >> 
> > PAGE_SHIFT;
> 
> Mmm, is there a reason for adding (i*PAGE_SIZE) before right-shifting?
> 
> > +        return map_frames_ex(mfns, n, 1, 0, 1, DOMID_IO, 0, 
> > _PAGE_PRESENT|_PAGE_RW);
> 
> Actually I think the whole could just be
> 
>       unsigned long first_mfn = offset >> PAGE_SHIFT;
>         return map_frames_ex(&first_mfn, n, 0, 1, 1, DOMID_IO, 0, 
> _PAGE_PRESENT|_PAGE_RW);
> 
> which avoids the need to prepare a table.

Yeah, you are right.
Both versions are fine for me.

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