Merge branch 'p2pdma-mmio-6.19.v5' into for-6.19/block

Merge MMIO P2P DMA series from Leon:

"This patch series improves block layer and NVMe driver support for MMIO
 memory regions, particularly for peer-to-peer (P2P) DMA transfers that
 go through the host bridge.

 The series addresses a critical gap where P2P transfers through the
 host bridge (PCI_P2PDMA_MAP_THRU_HOST_BRIDGE) were not properly marked
 as MMIO memory, leading to potential issues with:

 - Inappropriate CPU cache synchronization operations on MMIO regions
 - Incorrect DMA mapping/unmapping that doesn't respect MMIO semantics
 - Missing IOMMU configuration for MMIO memory handling

 This work is extracted from the larger DMA physical API improvement
 series [1] and focuses specifically on block layer and NVMe
 requirements for MMIO memory support.

 [1] https://lore.kernel.org/all/cover.1757423202.git.leonro@nvidia.com/"

Link: https://lore.kernel.org/linux-block/20251114-block-with-mmio-v5-0-69d00f73d766@nvidia.com/
Signed-off-by: Jens Axboe <axboe@kernel.dk>

* p2pdma-mmio-6.19.v5:
  block-dma: properly take MMIO path
  nvme-pci: migrate to dma_map_phys instead of map_page

4 files changed, 13 insertions, 32 deletions

diff --git a/include/linux/bio-integrity.h b/include/linux/bio-integrity.h
index 3d05296a5afe..21e4652dcfd2 100644
--- a/include/linux/bio-integrity.h
+++ b/include/linux/bio-integrity.h
@@ -13,7 +13,6 @@ enum bip_flags {
 	BIP_CHECK_GUARD		= 1 << 5, /* guard check */
 	BIP_CHECK_REFTAG	= 1 << 6, /* reftag check */
 	BIP_CHECK_APPTAG	= 1 << 7, /* apptag check */
-	BIP_P2P_DMA		= 1 << 8, /* using P2P address */
 
 	BIP_MEMPOOL		= 1 << 15, /* buffer backed by mempool */
 };
diff --git a/include/linux/blk-integrity.h b/include/linux/blk-integrity.h
index c2030fd8ba0a..a6b84206eb94 100644
--- a/include/linux/blk-integrity.h
+++ b/include/linux/blk-integrity.h
@@ -33,14 +33,6 @@ static inline bool queue_limits_stack_integrity_bdev(struct queue_limits *t,
 #ifdef CONFIG_BLK_DEV_INTEGRITY
 int blk_rq_map_integrity_sg(struct request *, struct scatterlist *);
 
-static inline bool blk_rq_integrity_dma_unmap(struct request *req,
-		struct device *dma_dev, struct dma_iova_state *state,
-		size_t mapped_len)
-{
-	return blk_dma_unmap(req, dma_dev, state, mapped_len,
-			bio_integrity(req->bio)->bip_flags & BIP_P2P_DMA);
-}
-
 int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
 int blk_rq_integrity_map_user(struct request *rq, void __user *ubuf,
 			      ssize_t bytes);
@@ -129,12 +121,6 @@ static inline int blk_rq_map_integrity_sg(struct request *q,
 {
 	return 0;
 }
-static inline bool blk_rq_integrity_dma_unmap(struct request *req,
-		struct device *dma_dev, struct dma_iova_state *state,
-		size_t mapped_len)
-{
-	return false;
-}
 static inline int blk_rq_integrity_map_user(struct request *rq,
 					    void __user *ubuf,
 					    ssize_t bytes)
diff --git a/include/linux/blk-mq-dma.h b/include/linux/blk-mq-dma.h
index 51829958d872..cb88fc791fbd 100644
--- a/include/linux/blk-mq-dma.h
+++ b/include/linux/blk-mq-dma.h
@@ -16,13 +16,13 @@ struct blk_dma_iter {
 	/* Output address range for this iteration */
 	dma_addr_t			addr;
 	u32				len;
+	struct pci_p2pdma_map_state	p2pdma;
 
 	/* Status code. Only valid when blk_rq_dma_map_iter_* returned false */
 	blk_status_t			status;
 
 	/* Internal to blk_rq_dma_map_iter_* */
 	struct blk_map_iter		iter;
-	struct pci_p2pdma_map_state	p2pdma;
 };
 
 bool blk_rq_dma_map_iter_start(struct request *req, struct device *dma_dev,
@@ -43,36 +43,34 @@ static inline bool blk_rq_dma_map_coalesce(struct dma_iova_state *state)
 }
 
 /**
- * blk_dma_unmap - try to DMA unmap a request
+ * blk_rq_dma_unmap - try to DMA unmap a request
  * @req:	request to unmap
  * @dma_dev:	device to unmap from
  * @state:	DMA IOVA state
  * @mapped_len: number of bytes to unmap
- * @is_p2p:	true if mapped with PCI_P2PDMA_MAP_BUS_ADDR
+ * @map:	peer-to-peer mapping type
  *
  * Returns %false if the callers need to manually unmap every DMA segment
  * mapped using @iter or %true if no work is left to be done.
  */
-static inline bool blk_dma_unmap(struct request *req, struct device *dma_dev,
-		struct dma_iova_state *state, size_t mapped_len, bool is_p2p)
+static inline bool blk_rq_dma_unmap(struct request *req, struct device *dma_dev,
+		struct dma_iova_state *state, size_t mapped_len,
+		enum pci_p2pdma_map_type map)
 {
-	if (is_p2p)
+	if (map == PCI_P2PDMA_MAP_BUS_ADDR)
 		return true;
 
 	if (dma_use_iova(state)) {
+		unsigned int attrs = 0;
+
+		if (map == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE)
+			attrs |= DMA_ATTR_MMIO;
+
 		dma_iova_destroy(dma_dev, state, mapped_len, rq_dma_dir(req),
-				 0);
+				 attrs);
 		return true;
 	}
 
 	return !dma_need_unmap(dma_dev);
 }
-
-static inline bool blk_rq_dma_unmap(struct request *req, struct device *dma_dev,
-		struct dma_iova_state *state, size_t mapped_len)
-{
-	return blk_dma_unmap(req, dma_dev, state, mapped_len,
-				req->cmd_flags & REQ_P2PDMA);
-}
-
 #endif /* BLK_MQ_DMA_H */
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 53501ebb0623..d884cc1256ec 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -393,7 +393,6 @@ enum req_flag_bits {
 	__REQ_DRV,		/* for driver use */
 	__REQ_FS_PRIVATE,	/* for file system (submitter) use */
 	__REQ_ATOMIC,		/* for atomic write operations */
-	__REQ_P2PDMA,		/* contains P2P DMA pages */
 	/*
 	 * Command specific flags, keep last:
 	 */
@@ -426,7 +425,6 @@ enum req_flag_bits {
 #define REQ_DRV		(__force blk_opf_t)(1ULL << __REQ_DRV)
 #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_NOUNMAP	(__force blk_opf_t)(1ULL << __REQ_NOUNMAP)