Re: [BLOCK] bh: Ensure bh fits within a page

From: Jens Axboe
Date: Wed Aug 02 2006 - 07:09:10 EST


On Wed, Aug 02 2006, Herbert Xu wrote:
> On Tue, Aug 01, 2006 at 09:33:54PM +0200, Andi Kleen wrote:
> > > diff --git a/fs/buffer.c b/fs/buffer.c
> > > index 71649ef..b998f08 100644
> > > --- a/fs/buffer.c
> > > +++ b/fs/buffer.c
> > > @@ -2790,6 +2790,7 @@ int submit_bh(int rw, struct buffer_head
> > > BUG_ON(!buffer_locked(bh));
> > > BUG_ON(!buffer_mapped(bh));
> > > BUG_ON(!bh->b_end_io);
> > > + WARN_ON(bh_offset(bh) + bh->b_size > PAGE_SIZE);
> >
> > What happens when someone implements direct large page IO?
>
> Then they'll need to change submit_bh to generate more than one bvec.
> At that time they can remove this warning :)

Or just use a proper interface, no new code should touch submit_bh().

--
Jens Axboe

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