arm64: Remove pointless WARN_ON in DMA teardown

We expect arch_teardown_dma_ops() to be called very late in a device's
life, after it has been removed from its bus, and thus after the IOMMU
bus notifier has run. As such, even if this funny little check did make
sense, it's unlikely to achieve what it thinks it's trying to do anyway.
It's a residual trace of an earlier implementation which didn't belong
here from the start; belatedly snuff it out.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 3f74d0d98de63322b15b387cb967009db17079ff..aa6c8f834d9e43927683a17f16f4bd9d53e167ec 100644 (file)
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -938,11 +938,6 @@ static void __iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
 
 void arch_teardown_dma_ops(struct device *dev)
 {
-       struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
-
-       if (WARN_ON(domain))
-               iommu_detach_device(domain, dev);
-
        dev->archdata.dma_ops = NULL;
 }