1 files changed, 31 insertions, 62 deletions

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 462b429ad243..4496a7c5c478 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -10,6 +10,7 @@
 
 #define pr_fmt(fmt) "pci-p2pdma: " fmt
 #include <linux/ctype.h>
+#include <linux/dma-map-ops.h>
 #include <linux/pci-p2pdma.h>
 #include <linux/module.h>
 #include <linux/slab.h>
@@ -20,13 +21,6 @@
 #include <linux/seq_buf.h>
 #include <linux/xarray.h>
 
-enum pci_p2pdma_map_type {
-	PCI_P2PDMA_MAP_UNKNOWN = 0,
-	PCI_P2PDMA_MAP_NOT_SUPPORTED,
-	PCI_P2PDMA_MAP_BUS_ADDR,
-	PCI_P2PDMA_MAP_THRU_HOST_BRIDGE,
-};
-
 struct pci_p2pdma {
 	struct gen_pool *pool;
 	bool p2pmem_published;
@@ -854,6 +848,7 @@ static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap,
 	struct pci_dev *provider = to_p2p_pgmap(pgmap)->provider;
 	struct pci_dev *client;
 	struct pci_p2pdma *p2pdma;
+	int dist;
 
 	if (!provider->p2pdma)
 		return PCI_P2PDMA_MAP_NOT_SUPPORTED;
@@ -870,74 +865,48 @@ static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap,
 		type = xa_to_value(xa_load(&p2pdma->map_types,
 					   map_types_idx(client)));
 	rcu_read_unlock();
-	return type;
-}
 
-static int __pci_p2pdma_map_sg(struct pci_p2pdma_pagemap *p2p_pgmap,
-		struct device *dev, struct scatterlist *sg, int nents)
-{
-	struct scatterlist *s;
-	int i;
-
-	for_each_sg(sg, s, nents, i) {
-		s->dma_address = sg_phys(s) + p2p_pgmap->bus_offset;
-		sg_dma_len(s) = s->length;
-	}
+	if (type == PCI_P2PDMA_MAP_UNKNOWN)
+		return calc_map_type_and_dist(provider, client, &dist, true);
 
-	return nents;
+	return type;
 }
 
 /**
- * pci_p2pdma_map_sg_attrs - map a PCI peer-to-peer scatterlist for DMA
- * @dev: device doing the DMA request
- * @sg: scatter list to map
- * @nents: elements in the scatterlist
- * @dir: DMA direction
- * @attrs: DMA attributes passed to dma_map_sg() (if called)
+ * pci_p2pdma_map_segment - map an sg segment determining the mapping type
+ * @state: State structure that should be declared outside of the for_each_sg()
+ *	loop and initialized to zero.
+ * @dev: DMA device that's doing the mapping operation
+ * @sg: scatterlist segment to map
  *
- * Scatterlists mapped with this function should be unmapped using
- * pci_p2pdma_unmap_sg_attrs().
+ * This is a helper to be used by non-IOMMU dma_map_sg() implementations where
+ * the sg segment is the same for the page_link and the dma_address.
  *
- * Returns the number of SG entries mapped or 0 on error.
+ * Attempt to map a single segment in an SGL with the PCI bus address.
+ * The segment must point to a PCI P2PDMA page and thus must be
+ * wrapped in a is_pci_p2pdma_page(sg_page(sg)) check.
+ *
+ * Returns the type of mapping used and maps the page if the type is
+ * PCI_P2PDMA_MAP_BUS_ADDR.
  */
-int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
-		int nents, enum dma_data_direction dir, unsigned long attrs)
+enum pci_p2pdma_map_type
+pci_p2pdma_map_segment(struct pci_p2pdma_map_state *state, struct device *dev,
+		       struct scatterlist *sg)
 {
-	struct pci_p2pdma_pagemap *p2p_pgmap =
-		to_p2p_pgmap(sg_page(sg)->pgmap);
-
-	switch (pci_p2pdma_map_type(sg_page(sg)->pgmap, dev)) {
-	case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE:
-		return dma_map_sg_attrs(dev, sg, nents, dir, attrs);
-	case PCI_P2PDMA_MAP_BUS_ADDR:
-		return __pci_p2pdma_map_sg(p2p_pgmap, dev, sg, nents);
-	default:
-		WARN_ON_ONCE(1);
-		return 0;
+	if (state->pgmap != sg_page(sg)->pgmap) {
+		state->pgmap = sg_page(sg)->pgmap;
+		state->map = pci_p2pdma_map_type(state->pgmap, dev);
+		state->bus_off = to_p2p_pgmap(state->pgmap)->bus_offset;
 	}
-}
-EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg_attrs);
 
-/**
- * pci_p2pdma_unmap_sg_attrs - unmap a PCI peer-to-peer scatterlist that was
- *	mapped with pci_p2pdma_map_sg()
- * @dev: device doing the DMA request
- * @sg: scatter list to map
- * @nents: number of elements returned by pci_p2pdma_map_sg()
- * @dir: DMA direction
- * @attrs: DMA attributes passed to dma_unmap_sg() (if called)
- */
-void pci_p2pdma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg,
-		int nents, enum dma_data_direction dir, unsigned long attrs)
-{
-	enum pci_p2pdma_map_type map_type;
-
-	map_type = pci_p2pdma_map_type(sg_page(sg)->pgmap, dev);
+	if (state->map == PCI_P2PDMA_MAP_BUS_ADDR) {
+		sg->dma_address = sg_phys(sg) + state->bus_off;
+		sg_dma_len(sg) = sg->length;
+		sg_dma_mark_bus_address(sg);
+	}
 
-	if (map_type == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE)
-		dma_unmap_sg_attrs(dev, sg, nents, dir, attrs);
+	return state->map;
 }
-EXPORT_SYMBOL_GPL(pci_p2pdma_unmap_sg_attrs);
 
 /**
  * pci_p2pdma_enable_store - parse a configfs/sysfs attribute store