intel-iommu: Add iommu_should_identity_map() function

We do this twice, and it's about to get more complicated. This makes the
code slightly clearer about what it's doing, too.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 73a5c71dd37d..ae5ccdf8b19f 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -2442,6 +2442,11 @@ static int iommu_dummy(struct pci_dev *pdev)
         return pdev->dev.archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO;
 }
 
+static int iommu_should_identity_map(struct pci_dev *pdev)
+{
+        return pdev->dma_mask > DMA_BIT_MASK(32);
+}
+
 /* Check if the pdev needs to go through non-identity map and unmap process.*/
 static int iommu_no_mapping(struct pci_dev *pdev)
 {
@@ -2455,7 +2460,7 @@ static int iommu_no_mapping(struct pci_dev *pdev)
 
         found = identity_mapping(pdev);
         if (found) {
-                if (pdev->dma_mask > DMA_BIT_MASK(32))
+                if (iommu_should_identity_map(pdev))
                         return 1;
                 else {
                         /*
@@ -2472,7 +2477,7 @@ static int iommu_no_mapping(struct pci_dev *pdev)
                  * In case of a detached 64 bit DMA device from vm, the device
                  * is put into si_domain for identity mapping.
                  */
-                if (pdev->dma_mask > DMA_BIT_MASK(32)) {
+                if (iommu_should_identity_map(pdev)) {
                         int ret;
                         ret = domain_add_dev_info(si_domain, pdev);
                         if (ret)