Re: bio_chain: proposed solution for bio_alloc failure and large IO simplification

From: Jens Axboe (axboe@suse.de)
Date: Mon Jun 17 2002 - 01:37:28 EST

On Sat, Jun 15 2002, Adam J. Richter wrote:
> >> Can't I make a macro to do a table lookup from bio->bi_max?
>
> >Not really. If I do
>
> > bio_alloc(GFP_KERNEL, 27);
>
> >then I'll get a 32-slot bvec. But presumably, I don't
> >want to put more than 27 pages into it.
>
> If you called bio_alloc with a smaller number, that would
> just be the result of a small IO that you knew could not generate
> more iovecs than that. So, that scenario will not happen.

But the macro lookup would fail for bios not coming from bio_alloc() 

-- 
Jens Axboe

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