Re: [PATCH 02/10] block: copy bip_max_vcnt vecs instead of bip_vcnt during clone

Keith Busch
2024-04-30T08:25:43Z

On Mon, Apr 29, 2024 at 07:07:29PM +0200, Christoph Hellwig wrote:
> On Mon, Apr 29, 2024 at 01:04:12PM +0100, Keith Busch wrote:
> > An earlier version added a field in the bip to point to the original
> > bvec from the user address. That extra field wouldn't be used in the far
> > majority of cases, so moving the user bvec to the end of the existing
> > bip_vec is a spatial optimization. The code may look a little more
> > confusing that way, but I think it's better than making the bip bigger.
>
> I think we need to do something like that - just hiding the bounce
> buffer is not really maintainable once we get multiple levels of stacking
> and other creative bio cloning.

Not sure I follow that. From patches 2-4 here, I think that pretty much
covers it. It's just missing a good code comment, but the implementation
side looks complete for any amount of stacking and splitting.