x86/amd_gart: fix unmapping of non-GART mappings

In many cases we don't have to create a GART mapping at all, which
also means there is nothing to unmap.  Fix the range check that was
incorrectly modified when removing the mapping_error method.

Fixes: 9e8aa6b546 ("x86/amd_gart: remove the mapping_error dma_map_ops method")
Reported-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Michal Kubecek <mkubecek@suse.cz>

diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
index e0ff3ac8c127403a384b37c9ae15fe3902236f7d..2c0aa34af69c557a56dbf41fed11b595631434bd 100644 (file)
--- a/arch/x86/kernel/amd_gart_64.c
+++ b/arch/x86/kernel/amd_gart_64.c
@@ -256,7 +256,15 @@ static void gart_unmap_page(struct device *dev, dma_addr_t dma_addr,
        int npages;
        int i;
 
-       if (dma_addr == DMA_MAPPING_ERROR ||
+       if (WARN_ON_ONCE(dma_addr == DMA_MAPPING_ERROR))
+               return;
+
+       /*
+        * This driver will not always use a GART mapping, but might have
+        * created a direct mapping instead.  If that is the case there is
+        * nothing to unmap here.
+        */
+       if (dma_addr < iommu_bus_base ||
            dma_addr >= iommu_bus_base + iommu_size)
                return;