[PATCH 13/19] dma-iommu: don't remap contiguous allocations for coherent devices

[Christoph Hellwig]

There is no need to remap for pte attributes, or for a virtually
contiguous address, so just don't do it.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 drivers/iommu/dma-iommu.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index c9788e0c1d5d..710814a370b9 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -1041,10 +1041,10 @@ static void *iommu_dma_alloc(struct device *dev, size_t 
size,
 
                addr = iommu_dma_alloc_contiguous(dev, iosize, handle, gfp,
                                attrs);
-               if (!addr)
-                       return NULL;
-               page = virt_to_page(addr);
+               if (coherent || !addr)
+                       return addr;
 
+               page = virt_to_page(addr);
                addr = dma_common_contiguous_remap(page, size, VM_USERMAP, prot,
                                __builtin_return_address(0));
                if (!addr) {
@@ -1052,8 +1052,7 @@ static void *iommu_dma_alloc(struct device *dev, size_t 
size,
                        return NULL;
                }
 
-               if (!coherent)
-                       arch_dma_prep_coherent(page, iosize);
+               arch_dma_prep_coherent(page, iosize);
        } else {
                addr = iommu_dma_alloc_remap(dev, iosize, handle, gfp, attrs);
        }
-- 
2.20.1