On Thu, Aug 28, 2025 at 09:19:20AM -0600, Keith Busch wrote:

On Tue, Aug 19, 2025 at 08:36:59PM +0300, Leon Romanovsky wrote:

quoted

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.

Before integrity metadata code was merged, the assumption was that request is
only one type or p2p or host. Is it still holding now?

And we can't store in dma_iova_state() as HMM/RDMA code works in page-based
granularity and one dma_iova_state() can mix different types.

Thanks