[PATCH 4/7] dma-mapping: Add helpers for dma_range_map bounds

[Christoph Hellwig]

On Wed, Nov 29, 2023 at 05:43:01PM +0000, Robin Murphy wrote:
> Several places want to compute the lower and/or upper bounds of a
> dma_range_map, so let's factor that out into reusable helpers.

As the build bot pointed out this will need a fix for the initialization
all-Fs for a 32-bit dma_addr_t, e.g. by using (dma_addr_t)-1, but
otherwise looks good:

Reviewed-by: Christoph Hellwig <hch at lst.de>