This helper returns if the device has issues addressing all present memory in the system.
Signed-off-by: Christoph Hellwig <[email protected]> --- include/linux/dma-mapping.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 8d13e28a8e07..e11b115dd0e4 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -679,6 +679,20 @@ static inline int dma_coerce_mask_and_coherent(struct device *dev, u64 mask) return dma_set_mask_and_coherent(dev, mask); } +/** + * dma_addressing_limited - return if the device is addressing limited + * @dev: device to check + * + * Return %true if the devices DMA mask is too small to address all memory in + * the system, else %false. Lack of addressing bits is the prime reason for + * bounce buffering, but might not be the only one. + */ +static inline bool dma_addressing_limited(struct device *dev) +{ + return min_not_zero(*dev->dma_mask, dev->bus_dma_mask) < + dma_get_required_mask(dev); +} + #ifdef CONFIG_ARCH_HAS_SETUP_DMA_OPS void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size, const struct iommu_ops *iommu, bool coherent); -- 2.20.1 _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
