iommu/amd: Skip attach device domain is same as new domain

If device->domain is same as new domain then we can skip the
device attach process.

Signed-off-by: Vasant Hegde <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Joerg Roedel <[email protected]>

Author: hegdevasant

drivers/iommu/amd/iommu.c

@@ -2184,6 +2184,13 @@ static int amd_iommu_attach_device(struct iommu_domain *dom,
 	struct amd_iommu *iommu = rlookup_amd_iommu(dev);
 	int ret;
 
+	/*
+	 * Skip attach device to domain if new domain is same as
+	 * devices current domain
+	 */
+	if (dev_data->domain == domain)
+		return 0;
+
 	dev_data->defer_attach = false;
 
 	if (dev_data->domain)