[PATCH v4 2/8] dma: contiguous: Make dev_get_cma_area() a proper function

Maxime Ripard
2026-03-31T10:00:27Z

As we try to enable dma-buf heaps, and the CMA one in particular, to
compile as modules, we need to export dev_get_cma_area(). It's currently
implemented as an inline function that returns either the content of
device->cma_area or dma_contiguous_default_area.

Thus, it means we need to export dma_contiguous_default_area, which
isn't really something we want any module to have access to.

Instead, let's make dev_get_cma_area() a proper function we will be able
to export so we can avoid exporting dma_contiguous_default_area.

Signed-off-by: Maxime Ripard <mripard@kernel.org>
---
include/linux/dma-map-ops.h | 7 +------
kernel/dma/contiguous.c | 8 ++++++++
2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index c4c93c72ff6ff3ff5c59b7161970805422e9dccb..8604106c0c01b6a9dadc45263f3b1d9ecfacd4aa 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -91,16 +91,11 @@ static inline void set_dma_ops(struct device *dev,
#endif /* CONFIG_ARCH_HAS_DMA_OPS */

#ifdef CONFIG_DMA_CMA
extern struct cma *dma_contiguous_default_area;

-static inline struct cma *dev_get_cma_area(struct device *dev)
-{
- if (dev && dev->cma_area)
- return dev->cma_area;
- return dma_contiguous_default_area;
-}
+struct cma *dev_get_cma_area(struct device *dev);
struct cma *dma_contiguous_get_area_by_idx(unsigned int idx);

void dma_contiguous_reserve(phys_addr_t addr_limit);
int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
phys_addr_t limit, struct cma **res_cma, bool fixed);
diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index afa9fd31304051d200cd4396dec26dd50becc375..40a0ead24979cfdf25e4779545536a5438e26356 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -129,10 +129,18 @@ early_param("cma", early_cma);
bool __init cma_skip_dt_default_reserved_mem(void)
{
return size_cmdline != -1;
}

+struct cma *dev_get_cma_area(struct device *dev)
+{
+ if (dev && dev->cma_area)
+ return dev->cma_area;
+
+ return dma_contiguous_default_area;
+}
+
#ifdef CONFIG_DMA_NUMA_CMA

static struct cma *dma_contiguous_numa_area[MAX_NUMNODES];
static phys_addr_t numa_cma_size[MAX_NUMNODES] __initdata;
static struct cma *dma_contiguous_pernuma_area[MAX_NUMNODES];

--
2.53.0