[RFC PATCH v2 2/5] dma-mapping: Use the correct phys_to_dma() for DMA_RESTRICTED_POOL

Mostafa Saleh
2026-03-30T14:51:33Z

As restricted dma pools are always decrypted, in swiotlb.c it uses
phys_to_dma_unencrypted() for address conversion.

However, in DMA-direct, calls to phys_to_dma_direct() with
force_dma_unencrypted() returning false, will fallback to
phys_to_dma() which is inconsistent for memory allocated from
restricted dma pools.

Fixes: f4111e39a52a ("swiotlb: Add restricted DMA alloc/free support")
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
kernel/dma/direct.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 27d804f0473f..1a402bb956d9 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -26,7 +26,7 @@ u64 zone_dma_limit __ro_after_init = DMA_BIT_MASK(24);
static inline dma_addr_t phys_to_dma_direct(struct device *dev,
phys_addr_t phys)
{
- if (force_dma_unencrypted(dev))
+ if (force_dma_unencrypted(dev) || is_swiotlb_for_alloc(dev))
return phys_to_dma_unencrypted(dev, phys);
return phys_to_dma(dev, phys);
}
--
2.53.0.1185.g05d4b7b318-goog