x86/amd-iommu: Cleanup attach/detach_device code

This patch cleans up the attach_device and detach_device
paths and fixes reference counting while at it.

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 530d608..e3363fd 100644 (file)
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -1329,7 +1329,6 @@ static bool dma_ops_domain(struct protection_domain *domain)
 
 static void set_dte_entry(u16 devid, struct protection_domain *domain)
 {
-       struct amd_iommu *iommu = amd_iommu_rlookup_table[devid];
        u64 pte_root = virt_to_phys(domain->pt_root);
 
        BUG_ON(amd_iommu_pd_table[devid] != NULL);
@@ -1344,18 +1343,11 @@ static void set_dte_entry(u16 devid, struct protection_domain *domain)
 
        amd_iommu_pd_table[devid] = domain;
 
-       /* Do reference counting */
-       domain->dev_iommu[iommu->index] += 1;
-       domain->dev_cnt                 += 1;
-
-       /* Flush the changes DTE entry */
-       iommu_queue_inv_dev_entry(iommu, devid);
 }
 
 static void clear_dte_entry(u16 devid)
 {
        struct protection_domain *domain = amd_iommu_pd_table[devid];
-       struct amd_iommu *iommu = amd_iommu_rlookup_table[devid];
 
        BUG_ON(domain == NULL);
 
@@ -1368,11 +1360,51 @@ static void clear_dte_entry(u16 devid)
        amd_iommu_dev_table[devid].data[2] = 0;
 
        amd_iommu_apply_erratum_63(devid);
+}
+
+static void do_attach(struct device *dev, struct protection_domain *domain)
+{
+       struct iommu_dev_data *dev_data;
+       struct amd_iommu *iommu;
+       u16 devid;
+
+       devid    = get_device_id(dev);
+       iommu    = amd_iommu_rlookup_table[devid];
+       dev_data = get_dev_data(dev);
+
+       /* Update data structures */
+       dev_data->domain = domain;
+       list_add(&dev_data->list, &domain->dev_list);
+       set_dte_entry(devid, domain);
+
+       /* Do reference counting */
+       domain->dev_iommu[iommu->index] += 1;
+       domain->dev_cnt                 += 1;
+
+       /* Flush the DTE entry */
+       iommu_queue_inv_dev_entry(iommu, devid);
+}
+
+static void do_detach(struct device *dev)
+{
+       struct iommu_dev_data *dev_data;
+       struct amd_iommu *iommu;
+       u16 devid;
+
+       devid    = get_device_id(dev);
+       iommu    = amd_iommu_rlookup_table[devid];
+       dev_data = get_dev_data(dev);
 
        /* decrease reference counters */
-       domain->dev_iommu[iommu->index] -= 1;
-       domain->dev_cnt                 -= 1;
+       dev_data->domain->dev_iommu[iommu->index] -= 1;
+       dev_data->domain->dev_cnt                 -= 1;
+
+       /* Update data structures */
+       dev_data->domain = NULL;
+       list_del(&dev_data->list);
+       clear_dte_entry(devid);
 
+       /* Flush the DTE entry */
        iommu_queue_inv_dev_entry(iommu, devid);
 }
 
@@ -1384,12 +1416,10 @@ static int __attach_device(struct device *dev,
                           struct protection_domain *domain)
 {
        struct iommu_dev_data *dev_data, *alias_data;
-       u16 devid, alias;
 
-       devid      = get_device_id(dev);
-       alias      = amd_iommu_alias_table[devid];
        dev_data   = get_dev_data(dev);
        alias_data = get_dev_data(dev_data->alias);
+
        if (!alias_data)
                return -EINVAL;
 
@@ -1406,21 +1436,16 @@ static int __attach_device(struct device *dev,
                return -EBUSY;
 
        /* Do real assignment */
-       if (alias != devid) {
-               if (alias_data->domain == NULL) {
-                       alias_data->domain = domain;
-                       list_add(&alias_data->list, &domain->dev_list);
-                       set_dte_entry(alias, domain);
-               }
+       if (dev_data->alias != dev) {
+               alias_data = get_dev_data(dev_data->alias);
+               if (alias_data->domain == NULL)
+                       do_attach(dev_data->alias, domain);
 
                atomic_inc(&alias_data->bind);
        }
 
-       if (dev_data->domain == NULL) {
-               dev_data->domain = domain;
-               list_add(&dev_data->list, &domain->dev_list);
-               set_dte_entry(devid, domain);
-       }
+       if (dev_data->domain == NULL)
+               do_attach(dev, domain);
 
        atomic_inc(&dev_data->bind);
 
@@ -1459,35 +1484,24 @@ static int attach_device(struct device *dev,
  */
 static void __detach_device(struct device *dev)
 {
-       u16 devid = get_device_id(dev), alias;
-       struct amd_iommu *iommu = amd_iommu_rlookup_table[devid];
        struct iommu_dev_data *dev_data = get_dev_data(dev);
        struct iommu_dev_data *alias_data;
        unsigned long flags;
 
-       BUG_ON(!iommu);
+       BUG_ON(!dev_data->domain);
 
-       devid = get_device_id(dev);
-       alias = get_device_id(dev_data->alias);
+       spin_lock_irqsave(&dev_data->domain->lock, flags);
 
-       if (devid != alias) {
+       if (dev_data->alias != dev) {
                alias_data = get_dev_data(dev_data->alias);
-               if (atomic_dec_and_test(&alias_data->bind)) {
-                       spin_lock_irqsave(&alias_data->domain->lock, flags);
-                       clear_dte_entry(alias);
-                       list_del(&alias_data->list);
-                       spin_unlock_irqrestore(&alias_data->domain->lock, flags);
-                       alias_data->domain = NULL;
-               }
+               if (atomic_dec_and_test(&alias_data->bind))
+                       do_detach(dev_data->alias);
        }
 
-       if (atomic_dec_and_test(&dev_data->bind)) {
-               spin_lock_irqsave(&dev_data->domain->lock, flags);
-               clear_dte_entry(devid);
-               list_del(&dev_data->list);
-               spin_unlock_irqrestore(&dev_data->domain->lock, flags);
-               dev_data->domain = NULL;
-       }
+       if (atomic_dec_and_test(&dev_data->bind))
+               do_detach(dev);
+
+       spin_unlock_irqrestore(&dev_data->domain->lock, flags);
 
        /*
         * If we run in passthrough mode the device must be assigned to the