arm64/dma-mapping: Mildly optimise non-coherent IOMMU ops

fix #27432135

commit 7adb562c3e90f87b0da196c372afe251ad4ec62e upstream

Whilst the symmetry of deferring to the existing sync callback in
__iommu_map_page() is nice, taking a round-trip through
iommu_iova_to_phys() is a pretty heavyweight way to get an address we
can trivially compute from the page we already have. Tweaking it to just
perform the cache maintenance directly when appropriate doesn't really
make the code any more complicated, and the runtime efficiency gain can
only be a benefit.

Furthermore, the sync operations themselves know they can only be
invoked on a managed DMA ops domain, so can use the fast specific domain
lookup to avoid excessive manipulation of the group refcount
(particularly in the scatterlist cases).
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Tested-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NRongwei Wang <rongwei.wang@linux.alibaba.com>
Acked-by: Nzou cao <zoucao@linux.alibaba.com>

arch/arm64/mm/dma-mapping.c

@@ -722,7 +722,7 @@ static void __iommu_sync_single_for_cpu(struct device *dev,
 	if (is_device_dma_coherent(dev))
 		return;
 
-	phys = iommu_iova_to_phys(iommu_get_domain_for_dev(dev), dev_addr);
+	phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dev_addr);
 	__dma_unmap_area(phys_to_virt(phys), size, dir);
 }
 
@@ -735,7 +735,7 @@ static void __iommu_sync_single_for_device(struct device *dev,
 	if (is_device_dma_coherent(dev))
 		return;
 
-	phys = iommu_iova_to_phys(iommu_get_domain_for_dev(dev), dev_addr);
+	phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dev_addr);
 	__dma_map_area(phys_to_virt(phys), size, dir);
 }
 
@@ -748,9 +748,9 @@ static dma_addr_t __iommu_map_page(struct device *dev, struct page *page,
 	int prot = dma_info_to_prot(dir, coherent, attrs);
 	dma_addr_t dev_addr = iommu_dma_map_page(dev, page, offset, size, prot);
 
-	if (!iommu_dma_mapping_error(dev, dev_addr) &&
-	    (attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
-		__iommu_sync_single_for_device(dev, dev_addr, size, dir);
+	if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
+	    !iommu_dma_mapping_error(dev, dev_addr))
+		__dma_map_area(page_address(page) + offset, size, dir);
 
 	return dev_addr;
 }