7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peng Fan [ Upstream commit 057e5e07420c753f248f9ce148040ab6dcf8359f ] MMIO resources mapped via dma_map_resource() carry DMA_ATTR_MMIO. These never need swiotlb bounce buffering, but the current code enters the swiotlb path when the physical address is not page-aligned, then rejects the mapping because MMIO cannot be bounced. Move the DMA_ATTR_MMIO check before the swiotlb block so the entire bounce path is skipped for MMIO, falling through directly to __iommu_dma_map() which creates the IOVA mapping. Fixes: f9374de14c0e8 ("iommu/dma: implement DMA_ATTR_MMIO for iommu_dma_(un)map_phys()") Assisted-by: Claude:claude-opus-4-6 Signed-off-by: Peng Fan Acked-by: Robin Murphy Link: https://lore.kernel.org/r/20260916-iommu-dma-fix-v1-1-a59a0c45ec5b@nxp.com Signed-off-by: Marek Szyprowski Signed-off-by: Sasha Levin --- drivers/iommu/dma-iommu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index ae814d8c99c04..5f901b4baf216 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -1228,9 +1228,9 @@ dma_addr_t iommu_dma_map_phys(struct device *dev, phys_addr_t phys, size_t size, * If both the physical buffer start address and size are page aligned, * we don't need to use a bounce page. */ - if (dev_use_swiotlb(dev, size, dir) && + if (!(attrs & DMA_ATTR_MMIO) && dev_use_swiotlb(dev, size, dir) && iova_unaligned(iovad, phys, size)) { - if (attrs & (DMA_ATTR_MMIO | DMA_ATTR_REQUIRE_COHERENT)) + if (attrs & DMA_ATTR_REQUIRE_COHERENT) return DMA_MAPPING_ERROR; phys = iommu_dma_map_swiotlb(dev, phys, size, dir, attrs); -- 2.53.0