iommu/vt-d: Move domain helper to header

Move domain helper to header to be used by SVA code.
Signed-off-by: NJacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: NLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: NEric Auger <eric.auger@redhat.com>
Reviewed-by: NKevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20200516062101.29541-2-baolu.lu@linux.intel.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

drivers/iommu/intel-iommu.c

@@ -441,12 +441,6 @@ static void init_translation_status(struct intel_iommu *iommu)
 		iommu->flags |= VTD_FLAG_TRANS_PRE_ENABLED;
 }
 
-/* Convert generic 'struct iommu_domain to private struct dmar_domain */
-static struct dmar_domain *to_dmar_domain(struct iommu_domain *dom)
-{
-	return container_of(dom, struct dmar_domain, domain);
-}
-
 static int __init intel_iommu_setup(char *str)
 {
 	if (!str)

include/linux/intel-iommu.h

@@ -595,6 +595,12 @@ static inline void __iommu_flush_cache(
 		clflush_cache_range(addr, size);
 }
 
+/* Convert generic struct iommu_domain to private struct dmar_domain */
+static inline struct dmar_domain *to_dmar_domain(struct iommu_domain *dom)
+{
+	return container_of(dom, struct dmar_domain, domain);
+}
+
 /*
  * 0: readable
  * 1: writable