On 07.11.2014 13:21, Zoltan Kiss wrote: > > > On 07/11/14 12:15, Stefan Bader wrote: >> On 07.11.2014 12:22, Eric Dumazet wrote: >>> On Fri, 2014-11-07 at 09:25 +0000, Zoltan Kiss wrote: >>> >>> Please do not top post. >>> >>>> Hi, >>>> >>>> AFAIK in this scenario your skb frag is wrong. The page pointer should >>>> point to the original compound page (not a member of it), and offset >>>> should be set accordingly. >>>> For example, if your compound page is 16K (4 page), then the page >>>> pointer should point to the first page, and if the data starts at the >>>> 3rd page, then offset should be >8K >>> >>> This is not accurate. >>> >>> This BUG_ON() is wrong. >>> >>> It should instead be : >>> >>> BUG_ON(len + offset > PAGE_SIZE<<compound_order(compound_head(page))); >> >> would that not have to be >> >> BUG_ON((page-compound_head(page)*PAGE_SIZE)+offset+len > >> PAGE_SIZE<<compound_order(compound_head(page))); > > There should be a parentheses around "page-compound_head(page)".
*sigh* before submitting anything I'll have to make sure I run it past the compiler at least. I never manager to type the beast without some error. But you got the drift... >> >> since offset is adjusted to start from the tail page in that case. >>> >>> splice() code can generate such cases. >>> >>> >> >>
signature.asc
Description: OpenPGP digital signature
