Re: [PATCH v4 15/16] block-dma: properly take MMIO path

[Keith Busch <kbusch@xxxxxxxxxx>]

On Tue, Aug 19, 2025 at 08:36:59PM +0300, Leon Romanovsky wrote:
> diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
> index 09b99d52fd36..283058bcb5b1 100644
> --- a/include/linux/blk_types.h
> +++ b/include/linux/blk_types.h
> @@ -387,6 +387,7 @@ enum req_flag_bits {
>       __REQ_FS_PRIVATE,       /* for file system (submitter) use */
>       __REQ_ATOMIC,           /* for atomic write operations */
>       __REQ_P2PDMA,           /* contains P2P DMA pages */
> +     __REQ_MMIO,             /* contains MMIO memory */
>       /*
>        * Command specific flags, keep last:
>        */
> @@ -420,6 +421,7 @@ enum req_flag_bits {
>  #define REQ_FS_PRIVATE       (__force blk_opf_t)(1ULL << __REQ_FS_PRIVATE)
>  #define REQ_ATOMIC   (__force blk_opf_t)(1ULL << __REQ_ATOMIC)
>  #define REQ_P2PDMA   (__force blk_opf_t)(1ULL << __REQ_P2PDMA)
> +#define REQ_MMIO     (__force blk_opf_t)(1ULL << __REQ_MMIO)

Now that my integrity metadata DMA series is staged, I don't think we
can use REQ flags like this because data and metadata may have different
mapping types. I think we should add a flags field to the dma_iova_state
instead.