On Sun, Nov 06, 2022 at 10:01:33PM +0000, Catalin Marinas wrote: > @@ -1202,7 +1203,10 @@ static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg, > goto out; > } > > - if (dev_use_swiotlb(dev)) > + if (dma_sg_kmalloc_needs_bounce(dev, sg, nents, dir)) > + sg_dma_mark_bounced(sg); > + > + if (dev_use_swiotlb(dev) || sg_is_dma_bounced(sg)) > return iommu_dma_map_sg_swiotlb(dev, sg, nents, dir, attrs); Shouldn't you add a similar check in the iommu_dma_unmap_sg() path to free any SWIOTLB memory that may have been allocated to bounce a scatter gather list?