From: Barry Song <[email protected]>

Apply batched DMA synchronization to iommu_dma_sync_sg_for_cpu() and
iommu_dma_sync_sg_for_device(). For all buffers in an SG list, only
a single flush operation is needed.

I do not have the hardware to test this, so the patch is marked as
RFC. I would greatly appreciate any testing feedback.

Cc: Leon Romanovsky <[email protected]>
Cc: Marek Szyprowski <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Ada Couprie Diaz <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Robin Murphy <[email protected]>
Cc: Joerg Roedel <[email protected]>
Cc: Tangquan Zheng <[email protected]>
Signed-off-by: Barry Song <[email protected]>
---
 drivers/iommu/dma-iommu.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index ffa940bdbbaf..b68dbfcb7846 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -1131,10 +1131,9 @@ void iommu_dma_sync_sg_for_cpu(struct device *dev, 
struct scatterlist *sgl,
                        iommu_dma_sync_single_for_cpu(dev, sg_dma_address(sg),
                                                      sg->length, dir);
        } else if (!dev_is_dma_coherent(dev)) {
-               for_each_sg(sgl, sg, nelems, i) {
+               for_each_sg(sgl, sg, nelems, i)
                        arch_sync_dma_for_cpu(sg_phys(sg), sg->length, dir);
-                       arch_sync_dma_flush();
-               }
+               arch_sync_dma_flush();
        }
 }
 
@@ -1144,16 +1143,16 @@ void iommu_dma_sync_sg_for_device(struct device *dev, 
struct scatterlist *sgl,
        struct scatterlist *sg;
        int i;
 
-       if (sg_dma_is_swiotlb(sgl))
+       if (sg_dma_is_swiotlb(sgl)) {
                for_each_sg(sgl, sg, nelems, i)
                        iommu_dma_sync_single_for_device(dev,
                                                         sg_dma_address(sg),
                                                         sg->length, dir);
-       else if (!dev_is_dma_coherent(dev))
-               for_each_sg(sgl, sg, nelems, i) {
+       } else if (!dev_is_dma_coherent(dev)) {
+               for_each_sg(sgl, sg, nelems, i)
                        arch_sync_dma_for_device(sg_phys(sg), sg->length, dir);
-                       arch_sync_dma_flush();
-               }
+               arch_sync_dma_flush();
+       }
 }
 
 static phys_addr_t iommu_dma_map_swiotlb(struct device *dev, phys_addr_t phys,
-- 
2.43.0


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