[PATCH] dma-mapping: Stub out dma_{alloc,free,map}_pages() API

From: James Clark
Date: Mon Jun 16 2025 - 07:19:31 EST


The implementations are in mapping.c which requires HAS_DMA so stub them
out if not present. This is required for some drivers to pass randconfig
builds.

Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-kbuild-all/202506160036.t9VDxF6p-lkp@xxxxxxxxx/
Signed-off-by: James Clark <james.clark@xxxxxxxxxx>
---
include/linux/dma-mapping.h | 28 +++++++++++++++++++++-------
1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 55c03e5fe8cb..766f28a0e11f 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -161,6 +161,12 @@ void *dma_vmap_noncontiguous(struct device *dev, size_t size,
void dma_vunmap_noncontiguous(struct device *dev, void *vaddr);
int dma_mmap_noncontiguous(struct device *dev, struct vm_area_struct *vma,
size_t size, struct sg_table *sgt);
+struct page *dma_alloc_pages(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp);
+void dma_free_pages(struct device *dev, size_t size, struct page *page,
+ dma_addr_t dma_handle, enum dma_data_direction dir);
+int dma_mmap_pages(struct device *dev, struct vm_area_struct *vma,
+ size_t size, struct page *page);
#else /* CONFIG_HAS_DMA */
static inline dma_addr_t dma_map_page_attrs(struct device *dev,
struct page *page, size_t offset, size_t size,
@@ -291,6 +297,21 @@ static inline int dma_mmap_noncontiguous(struct device *dev,
{
return -EINVAL;
}
+static inline struct page *dma_alloc_pages(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
+{
+ return NULL;
+}
+static inline void dma_free_pages(struct device *dev, size_t size,
+ struct page *page, dma_addr_t dma_handle,
+ enum dma_data_direction dir)
+{
+}
+static inline int dma_mmap_pages(struct device *dev, struct vm_area_struct *vma,
+ size_t size, struct page *page)
+{
+ return -EINVAL;
+}
#endif /* CONFIG_HAS_DMA */

#ifdef CONFIG_IOMMU_DMA
@@ -438,13 +459,6 @@ static inline bool dma_need_unmap(struct device *dev)
}
#endif /* !CONFIG_HAS_DMA || !CONFIG_DMA_NEED_SYNC */

-struct page *dma_alloc_pages(struct device *dev, size_t size,
- dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp);
-void dma_free_pages(struct device *dev, size_t size, struct page *page,
- dma_addr_t dma_handle, enum dma_data_direction dir);
-int dma_mmap_pages(struct device *dev, struct vm_area_struct *vma,
- size_t size, struct page *page);
-
static inline void *dma_alloc_noncoherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
{
--
2.34.1