Re: news about IDE PIO HIGHMEM bug

Jeff Garzik
2004-10-27T18:33:45Z

Christoph Hellwig wrote:
>>To repeat what I said in IRC ... ;-)
>>
>>Actually, you could check this with the pfns being the same when >> MAX_ORDER-1.
>>We should be aligned on a MAX_ORDER boundary, I think.
>>
>>However, pfn_to_page(page_to_pfn(page) + 1) might be safer. If rather slower.
>
>
> I think this is the wrong level of interface exposed. Just add two hepler
> kmap_atomic_sg/kunmap_atomic_sg that gurantee to map/unmap a sg list entry,
> even if it's bigger than a page.

Why bother mapping anything larger than a page, when none of the users
need it?

Jeff

P.S. In your scheme you would need four helpers; you forgot kmap_sg()
and kunmap_sg().