[PATCH 10/33] iommu/vt-d: Stop dmar_insert_dev_info() freeing domains on losing race

[David Woodhouse]

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.woodho...@intel.com>
---
 drivers/iommu/intel-iommu.c | 45 +++++++++++++++++++++------------------------
 1 file changed, 21 insertions(+), 24 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 1ab7c18..b50d1d6 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;
-- 
1.8.5.3

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