[PATCH v1 1/7] dma: make dma_mapping_error() NULL-safe

[Johannes Schneider]

dma_mapping_error() dereferenced dev->dma_mask unconditionally, while the
neighbouring cpu_to_dma()/dma_to_cpu() helpers already guard with 'dev &&'.
Callers with no device (e.g. the PBL SDHCI layer, which has no mci/device
yet) thus dereferenced a NULL pointer. Guard the dereference.

Assisted-by: Claude Opus 4.8 (1M context)
Signed-off-by: Johannes Schneider <johannes.schneider at leica-geosystems.com>
---
 include/dma.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/dma.h b/include/dma.h
index b8016c2e89..8f8ac78cdc 100644
--- a/include/dma.h
+++ b/include/dma.h
@@ -70,7 +70,7 @@ static inline void dma_set_mask(struct device *dev, u64 dma_mask)
 static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 {
 	return dma_addr == DMA_ERROR_CODE ||
-		(dev->dma_mask && dma_addr > dev->dma_mask);
+		(dev && dev->dma_mask && dma_addr > dev->dma_mask);
 }
 
 static inline dma_addr_t cpu_to_dma(struct device *dev, void *cpu_addr)

base-commit: da91ab6cb505fb09415bf8df3fae552e7b37c5e1
-- 
2.43.0