[PATCH v5 2/4] xen: do not return -EEXIST if iommu_add_dt_device is called twice

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

If both legacy IOMMU bindings and generic bindings are present,
iommu_add_dt_device can be called twice. Do not return error in that
case, that way there is no need to check for -EEXIST at the call sites.
Remove the one existing -EEXIT check, now unneeded.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
---
Changes in v5:
- new patch
---
 xen/drivers/passthrough/device_tree.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/xen/drivers/passthrough/device_tree.c 
b/xen/drivers/passthrough/device_tree.c
index 999b831d90..32526ecabb 100644
--- a/xen/drivers/passthrough/device_tree.c
+++ b/xen/drivers/passthrough/device_tree.c
@@ -140,8 +140,13 @@ int iommu_add_dt_device(struct dt_device_node *np)
     if ( !ops )
         return -EINVAL;
 
+    /*
+     * Some Device Trees may expose both legacy SMMU and generic
+     * IOMMU bindings together. If both are present, the device
+     * can be already added.
+     */
     if ( dev_iommu_fwspec_get(dev) )
-        return -EEXIST;
+        return 0;
 
     /*
      * According to the Documentation/devicetree/bindings/iommu/iommu.txt
@@ -254,7 +259,7 @@ int iommu_do_dt_domctl(struct xen_domctl *domctl, struct 
domain *d,
          * already added to the IOMMU (positive result). Such happens after
          * re-creating guest domain.
          */
-        if ( ret < 0 && ret != -EEXIST )
+        if ( ret < 0 )
         {
             printk(XENLOG_G_ERR "Failed to add %s to the IOMMU\n",
                    dt_node_full_name(dev));
-- 
2.17.1