iommu-dma direct call fixups

iommu-dma direct call fixups

[Christoph Hellwig]

Hi all,

this fixes a reported regression with the direct dma-iommu calls when
using the dma_alloc_noncontigous API, and also removes the not actually
needed stubs in iommu-dma.h that I noticed while looking at the header
again.

Diffstat:
 drivers/iommu/dma-iommu.c   |   33 ++++++++++++
 include/linux/dma-map-ops.h |   19 -------
 include/linux/iommu-dma.h   |  114 +++++---------------------------------------
 kernel/dma/mapping.c        |   37 +++-----------
 4 files changed, 57 insertions(+), 146 deletions(-)

[PATCH 1/2] dma-mapping: fix vmap and mmap of noncontiougs allocations

[Christoph Hellwig]

Commit b5c58b2fdc42 ("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: b5c58b2fdc42 ("dma-mapping: direct calls for dma-iommu")
Reported-by: Xi Ruoyao <xry111@xry111.site>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Xi Ruoyao <xry111@xry111.site>
---
 drivers/iommu/dma-iommu.c   | 33 +++++++++++++++++++++++++++++++++
 include/linux/dma-map-ops.h | 19 -------------------
 include/linux/iommu-dma.h   |  6 ++++++
 kernel/dma/mapping.c        | 37 ++++++++++---------------------------
 4 files changed, 49 insertions(+), 46 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 3672d619bcb691..2a9fa0c8cc00fe 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/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)
 {
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index 9668ddf3696e71..b7773201414c27 100644
--- a/include/linux/dma-map-ops.h
+++ b/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);
diff --git a/include/linux/iommu-dma.h b/include/linux/iommu-dma.h
index 1bb55ca1ab79d7..7bf145a52d6a1a 100644
--- a/include/linux/iommu-dma.h
+++ b/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,
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index b839683da0baf0..7911c754d9f42a 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -750,7 +750,6 @@ 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))
@@ -758,9 +757,7 @@ struct sg_table *dma_alloc_noncontiguous(struct device *dev, size_t size,
 	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);
-- 
2.45.2

Re: [PATCH 1/2] dma-mapping: fix vmap and mmap of noncontiougs allocations

[Leon Romanovsky]

On Sun, Sep 22, 2024 at 04:07:34PM +0200, Christoph Hellwig wrote:
> Commit b5c58b2fdc42 ("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: b5c58b2fdc42 ("dma-mapping: direct calls for dma-iommu")
> Reported-by: Xi Ruoyao <xry111@xry111.site>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Tested-by: Xi Ruoyao <xry111@xry111.site>
> ---
>  drivers/iommu/dma-iommu.c   | 33 +++++++++++++++++++++++++++++++++
>  include/linux/dma-map-ops.h | 19 -------------------
>  include/linux/iommu-dma.h   |  6 ++++++
>  kernel/dma/mapping.c        | 37 ++++++++++---------------------------
>  4 files changed, 49 insertions(+), 46 deletions(-)
> 

Thanks,
Reviewed-by: Leon Romanovsky <leon@kernel.org>

[PATCH 2/2] iommu/dma: remove most stubs in iommu-dma.h

[Christoph Hellwig]

The direct calls from mapping.c all guarded by use_dma_iommu(), so don't
bother to provide stubs, but instead just expose the prototypes
unconditionally.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/iommu-dma.h | 108 +++-----------------------------------
 1 file changed, 8 insertions(+), 100 deletions(-)

diff --git a/include/linux/iommu-dma.h b/include/linux/iommu-dma.h
index 7bf145a52d6a1a..508beaa44c39e8 100644
--- a/include/linux/iommu-dma.h
+++ b/include/linux/iommu-dma.h
@@ -14,6 +14,13 @@ static inline bool use_dma_iommu(struct device *dev)
 {
 	return dev->dma_iommu;
 }
+#else
+static inline bool use_dma_iommu(struct device *dev)
+{
+	return false;
+}
+#endif /* CONFIG_IOMMU_DMA */
+
 dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
 		unsigned long offset, size_t size, enum dma_data_direction dir,
 		unsigned long attrs);
@@ -58,104 +65,5 @@ void iommu_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sgl,
 		int nelems, enum dma_data_direction dir);
 void iommu_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sgl,
 		int nelems, enum dma_data_direction dir);
-#else
-static inline bool use_dma_iommu(struct device *dev)
-{
-	return false;
-}
-static inline dma_addr_t iommu_dma_map_page(struct device *dev,
-		struct page *page, unsigned long offset, size_t size,
-		enum dma_data_direction dir, unsigned long attrs)
-{
-	return DMA_MAPPING_ERROR;
-}
-static inline void iommu_dma_unmap_page(struct device *dev,
-		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir,
-		unsigned long attrs)
-{
-}
-static inline int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
-		int nents, enum dma_data_direction dir, unsigned long attrs)
-{
-	return -EINVAL;
-}
-static inline void iommu_dma_unmap_sg(struct device *dev,
-		struct scatterlist *sg, int nents, enum dma_data_direction dir,
-		unsigned long attrs)
-{
-}
-static inline void *iommu_dma_alloc(struct device *dev, size_t size,
-		dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
-{
-	return NULL;
-}
-static inline int iommu_dma_mmap(struct device *dev, struct vm_area_struct *vma,
-		void *cpu_addr, dma_addr_t dma_addr, size_t size,
-		unsigned long attrs)
-{
-	return -EINVAL;
-}
-static inline int iommu_dma_get_sgtable(struct device *dev,
-		struct sg_table *sgt, void *cpu_addr, dma_addr_t dma_addr,
-		size_t size, unsigned long attrs)
-{
-	return -EINVAL;
-}
-static inline unsigned long iommu_dma_get_merge_boundary(struct device *dev)
-{
-	return 0;
-}
-static inline size_t iommu_dma_opt_mapping_size(void)
-{
-	return 0;
-}
-static inline size_t iommu_dma_max_mapping_size(struct device *dev)
-{
-	return 0;
-}
-static inline void iommu_dma_free(struct device *dev, size_t size,
-		void *cpu_addr, dma_addr_t handle, unsigned long attrs)
-{
-}
-static inline dma_addr_t iommu_dma_map_resource(struct device *dev,
-		phys_addr_t phys, size_t size, enum dma_data_direction dir,
-		unsigned long attrs)
-{
-	return DMA_MAPPING_ERROR;
-}
-static inline void iommu_dma_unmap_resource(struct device *dev,
-		dma_addr_t handle, size_t size, enum dma_data_direction dir,
-		unsigned long attrs)
-{
-}
-static inline struct sg_table *
-iommu_dma_alloc_noncontiguous(struct device *dev, size_t size,
-		enum dma_data_direction dir, gfp_t gfp, unsigned long attrs)
-{
-	return NULL;
-}
-static inline void iommu_dma_free_noncontiguous(struct device *dev, size_t size,
-		struct sg_table *sgt, enum dma_data_direction dir)
-{
-}
-static inline void iommu_dma_sync_single_for_cpu(struct device *dev,
-		dma_addr_t dma_handle, size_t size,
-		enum dma_data_direction dir)
-{
-}
-static inline void iommu_dma_sync_single_for_device(struct device *dev,
-		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
-{
-}
-static inline void iommu_dma_sync_sg_for_cpu(struct device *dev,
-		struct scatterlist *sgl, int nelems,
-		enum dma_data_direction dir)
-{
-}
-static inline void iommu_dma_sync_sg_for_device(struct device *dev,
-		struct scatterlist *sgl, int nelems,
-		enum dma_data_direction dir)
-{
-}
-#endif /* CONFIG_IOMMU_DMA */
+
 #endif /* _LINUX_IOMMU_DMA_H */
-- 
2.45.2

Re: [PATCH 2/2] iommu/dma: remove most stubs in iommu-dma.h

[Leon Romanovsky]

On Sun, Sep 22, 2024 at 04:07:35PM +0200, Christoph Hellwig wrote:
> The direct calls from mapping.c all guarded by use_dma_iommu(), so don't
> bother to provide stubs, but instead just expose the prototypes
> unconditionally.

I was afraid to do such a change because of fear that some compiler will
call to the !CONFIG_IOMMU_DMA functions without checking the condition.

Thanks

> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  include/linux/iommu-dma.h | 108 +++-----------------------------------
>  1 file changed, 8 insertions(+), 100 deletions(-)
> 
> diff --git a/include/linux/iommu-dma.h b/include/linux/iommu-dma.h
> index 7bf145a52d6a1a..508beaa44c39e8 100644
> --- a/include/linux/iommu-dma.h
> +++ b/include/linux/iommu-dma.h
> @@ -14,6 +14,13 @@ static inline bool use_dma_iommu(struct device *dev)
>  {
>  	return dev->dma_iommu;
>  }
> +#else
> +static inline bool use_dma_iommu(struct device *dev)
> +{
> +	return false;
> +}
> +#endif /* CONFIG_IOMMU_DMA */
> +
>  dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
>  		unsigned long offset, size_t size, enum dma_data_direction dir,
>  		unsigned long attrs);
> @@ -58,104 +65,5 @@ void iommu_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sgl,
>  		int nelems, enum dma_data_direction dir);
>  void iommu_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sgl,
>  		int nelems, enum dma_data_direction dir);
> -#else
> -static inline bool use_dma_iommu(struct device *dev)
> -{
> -	return false;
> -}
> -static inline dma_addr_t iommu_dma_map_page(struct device *dev,
> -		struct page *page, unsigned long offset, size_t size,
> -		enum dma_data_direction dir, unsigned long attrs)
> -{
> -	return DMA_MAPPING_ERROR;
> -}
> -static inline void iommu_dma_unmap_page(struct device *dev,
> -		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir,
> -		unsigned long attrs)
> -{
> -}
> -static inline int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
> -		int nents, enum dma_data_direction dir, unsigned long attrs)
> -{
> -	return -EINVAL;
> -}
> -static inline void iommu_dma_unmap_sg(struct device *dev,
> -		struct scatterlist *sg, int nents, enum dma_data_direction dir,
> -		unsigned long attrs)
> -{
> -}
> -static inline void *iommu_dma_alloc(struct device *dev, size_t size,
> -		dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
> -{
> -	return NULL;
> -}
> -static inline int iommu_dma_mmap(struct device *dev, struct vm_area_struct *vma,
> -		void *cpu_addr, dma_addr_t dma_addr, size_t size,
> -		unsigned long attrs)
> -{
> -	return -EINVAL;
> -}
> -static inline int iommu_dma_get_sgtable(struct device *dev,
> -		struct sg_table *sgt, void *cpu_addr, dma_addr_t dma_addr,
> -		size_t size, unsigned long attrs)
> -{
> -	return -EINVAL;
> -}
> -static inline unsigned long iommu_dma_get_merge_boundary(struct device *dev)
> -{
> -	return 0;
> -}
> -static inline size_t iommu_dma_opt_mapping_size(void)
> -{
> -	return 0;
> -}
> -static inline size_t iommu_dma_max_mapping_size(struct device *dev)
> -{
> -	return 0;
> -}
> -static inline void iommu_dma_free(struct device *dev, size_t size,
> -		void *cpu_addr, dma_addr_t handle, unsigned long attrs)
> -{
> -}
> -static inline dma_addr_t iommu_dma_map_resource(struct device *dev,
> -		phys_addr_t phys, size_t size, enum dma_data_direction dir,
> -		unsigned long attrs)
> -{
> -	return DMA_MAPPING_ERROR;
> -}
> -static inline void iommu_dma_unmap_resource(struct device *dev,
> -		dma_addr_t handle, size_t size, enum dma_data_direction dir,
> -		unsigned long attrs)
> -{
> -}
> -static inline struct sg_table *
> -iommu_dma_alloc_noncontiguous(struct device *dev, size_t size,
> -		enum dma_data_direction dir, gfp_t gfp, unsigned long attrs)
> -{
> -	return NULL;
> -}
> -static inline void iommu_dma_free_noncontiguous(struct device *dev, size_t size,
> -		struct sg_table *sgt, enum dma_data_direction dir)
> -{
> -}
> -static inline void iommu_dma_sync_single_for_cpu(struct device *dev,
> -		dma_addr_t dma_handle, size_t size,
> -		enum dma_data_direction dir)
> -{
> -}
> -static inline void iommu_dma_sync_single_for_device(struct device *dev,
> -		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
> -{
> -}
> -static inline void iommu_dma_sync_sg_for_cpu(struct device *dev,
> -		struct scatterlist *sgl, int nelems,
> -		enum dma_data_direction dir)
> -{
> -}
> -static inline void iommu_dma_sync_sg_for_device(struct device *dev,
> -		struct scatterlist *sgl, int nelems,
> -		enum dma_data_direction dir)
> -{
> -}
> -#endif /* CONFIG_IOMMU_DMA */
> +
>  #endif /* _LINUX_IOMMU_DMA_H */
> -- 
> 2.45.2
> 

Re: [PATCH 2/2] iommu/dma: remove most stubs in iommu-dma.h

[Christoph Hellwig]

On Sun, Sep 22, 2024 at 05:28:19PM +0300, Leon Romanovsky wrote:
> On Sun, Sep 22, 2024 at 04:07:35PM +0200, Christoph Hellwig wrote:
> > The direct calls from mapping.c all guarded by use_dma_iommu(), so don't
> > bother to provide stubs, but instead just expose the prototypes
> > unconditionally.
> 
> I was afraid to do such a change because of fear that some compiler will
> call to the !CONFIG_IOMMU_DMA functions without checking the condition.

The kernel relies on this style of dead code elimination in many
places.  The IS_ENABLED() macro could not exist without it.

Re: [PATCH 2/2] iommu/dma: remove most stubs in iommu-dma.h

[Leon Romanovsky]

On Sun, Sep 22, 2024 at 04:07:35PM +0200, Christoph Hellwig wrote:
> The direct calls from mapping.c all guarded by use_dma_iommu(), so don't
> bother to provide stubs, but instead just expose the prototypes
> unconditionally.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  include/linux/iommu-dma.h | 108 +++-----------------------------------
>  1 file changed, 8 insertions(+), 100 deletions(-)
> 

Thanks,
Reviewed-by: Leon Romanovsky <leon@kernel.org>