Re: 5.10 regression caused by: "uas: fix sdev->host->dma_dev": many XHCI swiotlb buffer is full / DMAR: Device bounce map failed errors on thunderbolt connected XHCI controller

[Christoph Hellwig]

Can you give this one-liner a spin?

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index c6622011d4938c..e889111b55c71d 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4007,6 +4007,7 @@ static const struct dma_map_ops bounce_dma_ops = {
        .alloc_pages            = dma_common_alloc_pages,
        .free_pages             = dma_common_free_pages,
        .dma_supported          = dma_direct_supported,
+       .max_mapping_size       = swiotlb_max_mapping_size,
 };
 
 static inline int iommu_domain_cache_init(void)