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

[Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>]

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.

Samuel

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