[PATCHv2 1/7] blk-mq-dma: move the bio and bvec_iter to blk_dma_iter

[Christoph Hellwig]

On Sun, Jul 20, 2025 at 11:40:34AM -0700, Keith Busch wrote:
> From: Keith Busch <kbusch at kernel.org>
> 
> The req_iterator just happens to have a similar fields to what the dma
> iterator needs, but we're not necessarily iterating a bio_vec here. Have
> the dma iterator define its private fields directly. It also helps to
> remove eyesores like "iter->iter.iter".

Going back to this after looking at the later patches.  The level
for which this iter exists is only called blk_map_* as there is
nothing dma specific about, just mapping to physical addresses.

So maybe call it blk_map_iter instead?