Re: news about IDE PIO HIGHMEM bug (was: Re: 2.6.9-mm1)

Martin J. Bligh
2004-10-27T15:52:39Z

> Bartlomiej Zolnierkiewicz wrote:
>> We have stuct page of the first page and a offset.
>> We need to obtain struct page of the current page and map it.
>
>
> Opening this question to a wider audience.
>
> struct scatterlist gives us struct page*, and an offset+length pair. The struct page* is the _starting_ page of a potentially multi-page run of data.
>
> The question: how does one get struct page* for the second, and successive pages in a known-contiguous multi-page run, if one only knows the first page?

If it's a higher order allocation, just page+1 should be safe. If it just
happens to be contig, it might cross a discontig boundary, and not obey
that rule. Very unlikely, but possible.

M.