Re: remove block layer bounce buffering for MMC

[Robin Murphy]

On 14/01/2019 09:57, Christoph Hellwig wrote:
> Hi everyone,
>
> this series converts the remaining MMC host drivers to properly kmap the
> scatterlist entries it does PIO operations on, and then goes on to
> remove the usage of block layer bounce buffering (which I plan to remove
> eventually) from the MMC layer.
>
> As a bonus I've converted various drivers to the proper scatterlist
> helpers so that at least in theory they are ready for chained
> scatterlists.
>
> All the changes are compile tested only as I don't have any of the
> hardware, so a careful review would be appreciated.

One general point for the kmap() conversions - it's not obvious (to me 
at least) whether or how that would work for a segment where sg->length 
> PAGE_SIZE. Or is there some cast-iron guarantee from the MMC 
mid-layer that it will never let the block layer generate such things in 
the first place?

Robin.