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

[Christoph Hellwig]

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.