[PATCH 1/8] block: don't merge different kinds of P2P transfers in a single bio

[Keith Busch]

On Mon, Jun 23, 2025 at 04:12:23PM +0200, Christoph Hellwig wrote:
> To get out of the DMA mapping helpers having to check every segment for
> it's P2P status, ensure that bios either contain P2P transfers or non-P2P
> transfers, and that a P2P bio only contains ranges from a single device.
> 
> This means we do the page zone access in the bio add path where it should
> be still page hot, and will only have do the fairly expensive P2P topology
> lookup once per bio down in the DMA mapping path, and only for already
> marked bios.

Looks good.

Reviewed-by: Keith Busch <kbusch at kernel.org>