x86/amd-iommu: Allow dev_data->alias to be NULL

Let dev_data->alias be just NULL if the device has no alias.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index a15a172319099a056da0a9096a6965668a01fb8c..2d914a49b19a8eb774a6359f009832870ded0238 100644 (file)
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -183,12 +183,14 @@ static int iommu_init_device(struct device *dev)
                return -ENOMEM;
 
        alias = amd_iommu_alias_table[dev_data->devid];
-       pdev = pci_get_bus_and_slot(PCI_BUS(alias), alias & 0xff);
-       if (pdev)
-               dev_data->alias = &pdev->dev;
-       else {
-               free_dev_data(dev_data);
-               return -ENOTSUPP;
+       if (alias != dev_data->devid) {
+               pdev = pci_get_bus_and_slot(PCI_BUS(alias), alias & 0xff);
+               if (pdev)
+                       dev_data->alias = &pdev->dev;
+               else {
+                       free_dev_data(dev_data);
+                       return -ENOTSUPP;
+               }
        }
 
        dev->archdata.iommu = dev_data;
@@ -1604,29 +1606,31 @@ static void do_detach(struct iommu_dev_data *dev_data)
 static int __attach_device(struct iommu_dev_data *dev_data,
                           struct protection_domain *domain)
 {
-       struct iommu_dev_data *alias_data;
        int ret;
 
-       alias_data = get_dev_data(dev_data->alias);
-
-       if (!alias_data)
-               return -EINVAL;
-
        /* lock domain */
        spin_lock(&domain->lock);
 
-       /* Some sanity checks */
-       ret = -EBUSY;
-       if (alias_data->domain != NULL &&
-           alias_data->domain != domain)
-               goto out_unlock;
+       if (dev_data->alias != NULL) {
+               struct iommu_dev_data *alias_data;
+
+               alias_data = get_dev_data(dev_data->alias);
+
+               ret = -EINVAL;
+               if (!alias_data)
+                       goto out_unlock;
 
-       if (dev_data->domain != NULL &&
-           dev_data->domain != domain)
-               goto out_unlock;
+               /* Some sanity checks */
+               ret = -EBUSY;
+               if (alias_data->domain != NULL &&
+                               alias_data->domain != domain)
+                       goto out_unlock;
 
-       /* Do real assignment */
-       if (dev_data->devid != alias_data->devid) {
+               if (dev_data->domain != NULL &&
+                               dev_data->domain != domain)
+                       goto out_unlock;
+
+               /* Do real assignment */
                if (alias_data->domain == NULL)
                        do_attach(alias_data, domain);
 
@@ -1696,8 +1700,8 @@ static void __detach_device(struct iommu_dev_data *dev_data)
 
        spin_lock_irqsave(&domain->lock, flags);
 
-       alias_data = get_dev_data(dev_data->alias);
-       if (dev_data->devid != alias_data->devid) {
+       if (dev_data->alias) {
+               alias_data = get_dev_data(dev_data->alias);
                if (atomic_dec_and_test(&alias_data->bind))
                        do_detach(alias_data);
        }
@@ -1744,24 +1748,25 @@ static void detach_device(struct device *dev)
  */
 static struct protection_domain *domain_for_device(struct device *dev)
 {
-       struct protection_domain *dom;
        struct iommu_dev_data *dev_data, *alias_data;
+       struct protection_domain *dom = NULL;
        unsigned long flags;
 
        dev_data   = get_dev_data(dev);
-       alias_data = get_dev_data(dev_data->alias);
-       if (!alias_data)
-               return NULL;
 
-       read_lock_irqsave(&amd_iommu_devtable_lock, flags);
-       dom = dev_data->domain;
-       if (dom == NULL &&
-           alias_data->domain != NULL) {
-               __attach_device(dev_data, alias_data->domain);
-               dom = alias_data->domain;
-       }
+       if (dev_data->domain)
+               return dev_data->domain;
 
-       read_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
+       if (dev_data->alias != NULL) {
+               alias_data = get_dev_data(dev_data->alias);
+
+               read_lock_irqsave(&amd_iommu_devtable_lock, flags);
+               if (alias_data->domain != NULL) {
+                       __attach_device(dev_data, alias_data->domain);
+                       dom = alias_data->domain;
+               }
+               read_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
+       }
 
        return dom;
 }