Re: news about IDE PIO HIGHMEM bug

William Lee Irwin III
2004-10-27T18:48:36Z

Christoph Hellwig wrote:
>> 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.

On Wed, Oct 27, 2004 at 02:33:45PM -0400, Jeff Garzik wrote:
> Why bother mapping anything larger than a page, when none of the users
> need it?
> P.S. In your scheme you would need four helpers; you forgot kmap_sg()
> and kunmap_sg().

This is all a non-issue. The page structure just represents little more
than a physical address to the block layer in the context of merging,
so the pfn_to_page(page_to_pfn(...) + ...) bits calculate this properly.
There is just nothing interesting going on here. Generate the page
structure for the piece of the segment, kmap_atomic() it, and it's done.

-- wli