The dma masks in struct device are always 64-bits wide. But for builds
using a 32-bit dma_addr_t we need to ensure we don't store an
unsupportable value. Before Linux 5.0 this was handled at least by
the ARM dma mapping code by never allowing to set a larger dma_mask,
but these days we allow the driver to just set the largest supported
value and never fall back to a smaller one. Ensure this always works
by truncating the value.
Fixes:
9eb9e96e97b3 ("Documentation/DMA-API-HOWTO: update dma_mask sections")
Signed-off-by: Christoph Hellwig <hch@lst.de>
int dma_set_mask(struct device *dev, u64 mask)
{
+ /*
+ * Truncate the mask to the actually supported dma_addr_t width to
+ * avoid generating unsupportable addresses.
+ */
+ mask = (dma_addr_t)mask;
+
if (!dev->dma_mask || !dma_supported(dev, mask))
return -EIO;
#ifndef CONFIG_ARCH_HAS_DMA_SET_COHERENT_MASK
int dma_set_coherent_mask(struct device *dev, u64 mask)
{
+ /*
+ * Truncate the mask to the actually supported dma_addr_t width to
+ * avoid generating unsupportable addresses.
+ */
+ mask = (dma_addr_t)mask;
+
if (!dma_supported(dev, mask))
return -EIO;