Re: [Xen-devel] [PATCH] xen/netback: calculate correctly the SKB slots.

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Tue, May 22, 2012 at 03:01:55PM -0400, Simon Graham wrote:
> > >
> > > > >       int i, copy_off;
> > > > >
> > > > >       count = DIV_ROUND_UP(
> > > > > -                     offset_in_page(skb->data)+skb_headlen(skb),
> > PAGE_SIZE);
> > > > > +                     offset_in_page(skb->data + skb_headlen(skb)),
> > PAGE_SIZE);
> > > >
> > > > The new version would be equivalent to:
> > > >         count = offset_in_page(skb->data + skb_headlen(skb)) != 0;
> > > > which is not right, as netbk_gop_skb() will use one slot per page.
> > >
> > > Just outside the context of this patch we separately count the frag
> > > pages.
> > >
> > > However I think you are right if skb->data covers > 1 page, since the
> > > new version can only ever return 0 or 1. I expect this patch papers
> > over
> > > the underlying issue by not stopping often enough, rather than
> > actually
> > > fixing the underlying issue.
> > 
> > Ah, any thoughts? Have you guys seen this behavior as well?
> 
> We ran into this same problem and the fix we've been running with for a while 
> now (been meaning to submit it!) is:

Where is the patchqueue of the patches? Is it only on the src.rpm or
is it in some nice mercurial tree? Asking b/c if we run into other trouble
it would be also time-saving for us (and I presume other companies
too) to check that. Thanks!

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