dma-mapping: fix vmap and mmap of noncontiougs allocations

Commit b5c58b2 ("dma-mapping: direct calls for dma-iommu") switched
to use direct calls to dma-iommu, but missed the dma_vmap_noncontiguous,
dma_vunmap_noncontiguous and dma_mmap_noncontiguous behavior keyed off the
presence of the alloc_noncontiguous method.

Fix this by removing the now unused alloc_noncontiguous and
free_noncontiguous methods and moving the vmapping and mmaping of the
noncontiguous allocations into the iommu code, as it is the only provider
of actually noncontiguous allocations.

Fixes: b5c58b2 ("dma-mapping: direct calls for dma-iommu")
Reported-by: Xi Ruoyao <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Leon Romanovsky <[email protected]>
Tested-by: Xi Ruoyao <[email protected]>

Author: Christoph Hellwig

drivers/iommu/dma-iommu.c

@@ -1038,6 +1038,21 @@ static void *iommu_dma_alloc_remap(struct device *dev, size_t size,
 	return NULL;
 }
 
+/*
+ * This is the actual return value from the iommu_dma_alloc_noncontiguous.
+ *
+ * The users of the DMA API should only care about the sg_table, but to make
+ * the DMA-API internal vmaping and freeing easier we stash away the page
+ * array as well (except for the fallback case).  This can go away any time,
+ * e.g. when a vmap-variant that takes a scatterlist comes along.
+ */
+struct dma_sgt_handle {
+	struct sg_table sgt;
+	struct page **pages;
+};
+#define sgt_handle(sgt) \
+	container_of((sgt), struct dma_sgt_handle, sgt)
+
 struct sg_table *iommu_dma_alloc_noncontiguous(struct device *dev, size_t size,
 	       enum dma_data_direction dir, gfp_t gfp, unsigned long attrs)
 {
@@ -1066,6 +1081,24 @@ void iommu_dma_free_noncontiguous(struct device *dev, size_t size,
 	kfree(sh);
 }
 
+void *iommu_dma_vmap_noncontiguous(struct device *dev, size_t size,
+		struct sg_table *sgt)
+{
+	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+
+	return vmap(sgt_handle(sgt)->pages, count, VM_MAP, PAGE_KERNEL);
+}
+
+int iommu_dma_mmap_noncontiguous(struct device *dev, struct vm_area_struct *vma,
+		size_t size, struct sg_table *sgt)
+{
+	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+
+	if (vma->vm_pgoff >= count || vma_pages(vma) > count - vma->vm_pgoff)
+		return -ENXIO;
+	return vm_map_pages(vma, sgt_handle(sgt)->pages, count);
+}
+
 void iommu_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
 		size_t size, enum dma_data_direction dir)
 {

include/linux/dma-map-ops.h

@@ -24,11 +24,6 @@ struct dma_map_ops {
 			gfp_t gfp);
 	void (*free_pages)(struct device *dev, size_t size, struct page *vaddr,
 			dma_addr_t dma_handle, enum dma_data_direction dir);
-	struct sg_table *(*alloc_noncontiguous)(struct device *dev, size_t size,
-			enum dma_data_direction dir, gfp_t gfp,
-			unsigned long attrs);
-	void (*free_noncontiguous)(struct device *dev, size_t size,
-			struct sg_table *sgt, enum dma_data_direction dir);
 	int (*mmap)(struct device *, struct vm_area_struct *,
 			void *, dma_addr_t, size_t, unsigned long attrs);
 
@@ -206,20 +201,6 @@ static inline int dma_mmap_from_global_coherent(struct vm_area_struct *vma,
 }
 #endif /* CONFIG_DMA_GLOBAL_POOL */
 
-/*
- * This is the actual return value from the ->alloc_noncontiguous method.
- * The users of the DMA API should only care about the sg_table, but to make
- * the DMA-API internal vmaping and freeing easier we stash away the page
- * array as well (except for the fallback case).  This can go away any time,
- * e.g. when a vmap-variant that takes a scatterlist comes along.
- */
-struct dma_sgt_handle {
-	struct sg_table sgt;
-	struct page **pages;
-};
-#define sgt_handle(sgt) \
-	container_of((sgt), struct dma_sgt_handle, sgt)
-
 int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
 		void *cpu_addr, dma_addr_t dma_addr, size_t size,
 		unsigned long attrs);

include/linux/iommu-dma.h

@@ -44,6 +44,12 @@ struct sg_table *iommu_dma_alloc_noncontiguous(struct device *dev, size_t size,
 		enum dma_data_direction dir, gfp_t gfp, unsigned long attrs);
 void iommu_dma_free_noncontiguous(struct device *dev, size_t size,
 		struct sg_table *sgt, enum dma_data_direction dir);
+void *iommu_dma_vmap_noncontiguous(struct device *dev, size_t size,
+		struct sg_table *sgt);
+#define iommu_dma_vunmap_noncontiguous(dev, vaddr) \
+	vunmap(vaddr);
+int iommu_dma_mmap_noncontiguous(struct device *dev, struct vm_area_struct *vma,
+		size_t size, struct sg_table *sgt);
 void iommu_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
 		size_t size, enum dma_data_direction dir);
 void iommu_dma_sync_single_for_device(struct device *dev, dma_addr_t dma_handle,

kernel/dma/mapping.c

@@ -750,17 +750,14 @@ static struct sg_table *alloc_single_sgt(struct device *dev, size_t size,
 struct sg_table *dma_alloc_noncontiguous(struct device *dev, size_t size,
 		enum dma_data_direction dir, gfp_t gfp, unsigned long attrs)
 {
-	const struct dma_map_ops *ops = get_dma_ops(dev);
 	struct sg_table *sgt;
 
 	if (WARN_ON_ONCE(attrs & ~DMA_ATTR_ALLOC_SINGLE_PAGES))
 		return NULL;
 	if (WARN_ON_ONCE(gfp & __GFP_COMP))
 		return NULL;
 
-	if (ops && ops->alloc_noncontiguous)
-		sgt = ops->alloc_noncontiguous(dev, size, dir, gfp, attrs);
-	else if (use_dma_iommu(dev))
+	if (use_dma_iommu(dev))
 		sgt = iommu_dma_alloc_noncontiguous(dev, size, dir, gfp, attrs);
 	else
 		sgt = alloc_single_sgt(dev, size, dir, gfp);
@@ -786,13 +783,10 @@ static void free_single_sgt(struct device *dev, size_t size,
 void dma_free_noncontiguous(struct device *dev, size_t size,
 		struct sg_table *sgt, enum dma_data_direction dir)
 {
-	const struct dma_map_ops *ops = get_dma_ops(dev);
-
 	trace_dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir, 0);
 	debug_dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
-	if (ops && ops->free_noncontiguous)
-		ops->free_noncontiguous(dev, size, sgt, dir);
-	else if (use_dma_iommu(dev))
+
+	if (use_dma_iommu(dev))
 		iommu_dma_free_noncontiguous(dev, size, sgt, dir);
 	else
 		free_single_sgt(dev, size, sgt, dir);
@@ -802,37 +796,26 @@ EXPORT_SYMBOL_GPL(dma_free_noncontiguous);
 void *dma_vmap_noncontiguous(struct device *dev, size_t size,
 		struct sg_table *sgt)
 {
-	const struct dma_map_ops *ops = get_dma_ops(dev);
-	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 
-	if (ops && ops->alloc_noncontiguous)
-		return vmap(sgt_handle(sgt)->pages, count, VM_MAP, PAGE_KERNEL);
+	if (use_dma_iommu(dev))
+		return iommu_dma_vmap_noncontiguous(dev, size, sgt);
+
 	return page_address(sg_page(sgt->sgl));
 }
 EXPORT_SYMBOL_GPL(dma_vmap_noncontiguous);
 
 void dma_vunmap_noncontiguous(struct device *dev, void *vaddr)
 {
-	const struct dma_map_ops *ops = get_dma_ops(dev);
-
-	if (ops && ops->alloc_noncontiguous)
-		vunmap(vaddr);
+	if (use_dma_iommu(dev))
+		iommu_dma_vunmap_noncontiguous(dev, vaddr);
 }
 EXPORT_SYMBOL_GPL(dma_vunmap_noncontiguous);
 
 int dma_mmap_noncontiguous(struct device *dev, struct vm_area_struct *vma,
 		size_t size, struct sg_table *sgt)
 {
-	const struct dma_map_ops *ops = get_dma_ops(dev);
-
-	if (ops && ops->alloc_noncontiguous) {
-		unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
-
-		if (vma->vm_pgoff >= count ||
-		    vma_pages(vma) > count - vma->vm_pgoff)
-			return -ENXIO;
-		return vm_map_pages(vma, sgt_handle(sgt)->pages, count);
-	}
+	if (use_dma_iommu(dev))
+		return iommu_dma_mmap_noncontiguous(dev, vma, size, sgt);
 	return dma_mmap_pages(dev, vma, size, sg_page(sgt->sgl));
 }
 EXPORT_SYMBOL_GPL(dma_mmap_noncontiguous);