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>

1 files changed, 58 insertions, 44 deletions

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 530d6080940f..e3363fd5eef5 100644
--- 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