iommu/vt-d: Stop dmar_insert_dev_info() freeing domains on losing race

By moving this into get_domain_for_dev() we can make dmar_insert_dev_info()
suitable for use with "special" domains such as the si_domain, which
currently use domain_add_dev_info().

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

1 files changed, 21 insertions, 24 deletions

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 1c43a7b3008a..c1c564233768 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -2147,16 +2147,17 @@ dmar_search_domain_by_dev_info(int segment, int bus, int devfn)
         return NULL;
 }
 
-static int dmar_insert_dev_info(int segment, int bus, int devfn,
-                                struct device *dev, struct dmar_domain **domp)
+static struct dmar_domain *dmar_insert_dev_info(int segment, int bus, int devfn,
+                                                struct device *dev,
+                                                struct dmar_domain *domain)
 {
-        struct dmar_domain *found, *domain = *domp;
+        struct dmar_domain *found;
         struct device_domain_info *info;
         unsigned long flags;
 
         info = alloc_devinfo_mem();
         if (!info)
-                return -ENOMEM;
+                return NULL;
 
         info->segment = segment;
         info->bus = bus;
@@ -2174,19 +2175,17 @@ static int dmar_insert_dev_info(int segment, int bus, int devfn,
         if (found) {
                 spin_unlock_irqrestore(&device_domain_lock, flags);
                 free_devinfo_mem(info);
-                if (found != domain) {
-                        domain_exit(domain);
-                        *domp = found;
-                }
-        } else {
-                list_add(&info->link, &domain->devices);
-                list_add(&info->global, &device_domain_list);
-                if (dev)
-                        dev->archdata.iommu = info;
-                spin_unlock_irqrestore(&device_domain_lock, flags);
+                /* Caller must free the original domain */
+                return found;
         }
 
-        return 0;
+        list_add(&info->link, &domain->devices);
+        list_add(&info->global, &device_domain_list);
+        if (dev)
+                dev->archdata.iommu = info;
+        spin_unlock_irqrestore(&device_domain_lock, flags);
+
+        return domain;
 }
 
 /* domain is initialized */
@@ -2245,21 +2244,19 @@ static struct dmar_domain *get_domain_for_dev(struct pci_dev *pdev, int gaw)
 
         /* register pcie-to-pci device */
         if (dev_tmp) {
-                if (dmar_insert_dev_info(segment, bus, devfn, NULL, &domain))
+                domain = dmar_insert_dev_info(segment, bus, devfn, NULL, domain);
+                if (!domain)
                         goto error;
-                else
-                        free = NULL;
         }
 
 found_domain:
-        if (dmar_insert_dev_info(segment, pdev->bus->number, pdev->devfn,
-                                 &pdev->dev, &domain) == 0)
-                return domain;
+        domain = dmar_insert_dev_info(segment, pdev->bus->number, pdev->devfn,
+                                      &pdev->dev, domain);
 error:
-        if (free)
+        if (free != domain)
                 domain_exit(free);
-        /* recheck it here, maybe others set it */
-        return find_domain(&pdev->dev);
+
+        return domain;
 }
 
 static int iommu_identity_mapping;