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Subject[RFC 4/5] dma-direct: Allocate dma pages directly if global pool allocation fails
DMA_GLOBAL_POOL config may be enabled for platforms where global pool is
not supported because a generic defconfig is expected to boot on different
platforms. Specifically, some RISC-V platforms may use global pool for
non-coherent devices while some other platforms are completely coherent.
However, it is expected that single kernel image must boot on all the

Continue the dma direct allocation if a allocation from global pool failed.
This indicates that the platform is relying on some other method (direct
remap) or just have coherent devices.

Signed-off-by: Atish Patra <>
kernel/dma/direct.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index d1d0258ed6d0..984ea776f099 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -161,8 +161,11 @@ void *dma_direct_alloc(struct device *dev, size_t size,
return arch_dma_alloc(dev, size, dma_handle, gfp, attrs);

- !dev_is_dma_coherent(dev))
- return dma_alloc_from_global_coherent(dev, size, dma_handle);
+ !dev_is_dma_coherent(dev)) {
+ ret = dma_alloc_from_global_coherent(dev, size, dma_handle);
+ if (ret)
+ return ret;
+ }

* Remapping or decrypting memory may block. If either is required and
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