Messages in this thread Patch in this message | | | From | Lu Baolu <> | Subject | [PATCH v2 1/6] ARM/dma-mapping: Remove iommu_detach_device() | Date | Fri, 17 Feb 2023 17:47:31 +0800 |
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iommu_detach_device() attaches the default domain to the device, or if default domain is not supported by the IOMMU driver, it calls its set_platform_dma_ops callback. If the default domain is supported or the IOMMU driver is not iommu-dma aware, iommu_detach_device() is actually a noop.
The 64-bit ARM drivers always support default domain and iommu-dma is even not enabled for 32-bit ARM. This turns out that iommu_detach_device() is always a noop in arm_iommu_detach_device(). Remove it to avoid dead code.
The bonus is that it also removes a obstacle of arm_iommu_detach_device() re-entering the iommu core during release_device. With this removed, the iommu core code could be simplified a lot.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> --- arch/arm/mm/dma-mapping.c | 1 - 1 file changed, 1 deletion(-)
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 8bc01071474a..dcbc2f4586d4 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -1699,7 +1699,6 @@ void arm_iommu_detach_device(struct device *dev) return; } - iommu_detach_device(mapping->domain, dev); kref_put(&mapping->kref, release_iommu_mapping); to_dma_iommu_mapping(dev) = NULL; set_dma_ops(dev, NULL); -- 2.34.1
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