[Xen-changelog] [xen staging] VT-d/ATS: tidy device_in_domain()

[patchbot@xxxxxxx]

commit fa8f9792befc6ca4982d191b8b1e32f70087ee9d
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Sep 5 10:02:11 2019 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Sep 5 10:02:11 2019 +0200

    VT-d/ATS: tidy device_in_domain()
    
    Use appropriate types. Drop unnecessary casts. Check for failures which
    can (at least in theory because of non-obvious breakage elsewhere)
    occur, instead of ones which really can't (map_domain_page() won't
    return NULL).
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
---
 xen/drivers/passthrough/vtd/x86/ats.c | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/xen/drivers/passthrough/vtd/x86/ats.c 
b/xen/drivers/passthrough/vtd/x86/ats.c
index 1a3adb4acb..59722a751e 100644
--- a/xen/drivers/passthrough/vtd/x86/ats.c
+++ b/xen/drivers/passthrough/vtd/x86/ats.c
@@ -71,23 +71,25 @@ int ats_device(const struct pci_dev *pdev, const struct 
acpi_drhd_unit *drhd)
     return pos;
 }
 
-static int device_in_domain(const struct iommu *iommu,
-                            const struct pci_dev *pdev, u16 did)
+static bool device_in_domain(const struct iommu *iommu,
+                             const struct pci_dev *pdev, uint16_t did)
 {
-    struct root_entry *root_entry = NULL;
+    struct root_entry *root_entry;
     struct context_entry *ctxt_entry = NULL;
-    int tt, found = 0;
+    unsigned int tt;
+    bool found = false;
 
-    root_entry = (struct root_entry *) map_vtd_domain_page(iommu->root_maddr);
-    if ( !root_entry || !root_present(root_entry[pdev->bus]) )
-        goto out;
-
-    ctxt_entry = (struct context_entry *)
-                 map_vtd_domain_page(root_entry[pdev->bus].val);
+    if ( unlikely(!iommu->root_maddr) )
+    {
+        ASSERT_UNREACHABLE();
+        return false;
+    }
 
-    if ( ctxt_entry == NULL )
+    root_entry = map_vtd_domain_page(iommu->root_maddr);
+    if ( !root_present(root_entry[pdev->bus]) )
         goto out;
 
+    ctxt_entry = map_vtd_domain_page(root_entry[pdev->bus].val);
     if ( context_domain_id(ctxt_entry[pdev->devfn]) != did )
         goto out;
 
@@ -95,7 +97,7 @@ static int device_in_domain(const struct iommu *iommu,
     if ( tt != CONTEXT_TT_DEV_IOTLB )
         goto out;
 
-    found = 1;
+    found = true;
 out:
     if ( root_entry )
         unmap_vtd_domain_page(root_entry);
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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