iommu/vt-d: Use device_domain_lock accurately

The device_domain_lock is used to protect the device tracking list of
a domain. Remove unnecessary spin_lock/unlock()'s and move the necessary
ones around the list access.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20220706025524.2904370-11-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index ccddf634fae928ab653cecdc03006cddcc7595f6..ae42a9e43997376170319874ec2357f551320709 100644 (file)
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -535,15 +535,8 @@ static int domain_update_device_node(struct dmar_domain *domain)
        struct device_domain_info *info;
        int nid = NUMA_NO_NODE;
 
-       assert_spin_locked(&device_domain_lock);
-
-       if (list_empty(&domain->devices))
-               return NUMA_NO_NODE;
-
+       spin_lock(&device_domain_lock);
        list_for_each_entry(info, &domain->devices, link) {
-               if (!info->dev)
-                       continue;
-
                /*
                 * There could possibly be multiple device numa nodes as devices
                 * within the same domain may sit behind different IOMMUs. There
@@ -554,6 +547,7 @@ static int domain_update_device_node(struct dmar_domain *domain)
                if (nid != NUMA_NO_NODE)
                        break;
        }
+       spin_unlock(&device_domain_lock);
 
        return nid;
 }
@@ -1376,23 +1370,23 @@ static void __iommu_flush_iotlb(struct intel_iommu *iommu, u16 did,
 }
 
 static struct device_domain_info *
-iommu_support_dev_iotlb (struct dmar_domain *domain, struct intel_iommu *iommu,
-                        u8 bus, u8 devfn)
+iommu_support_dev_iotlb(struct dmar_domain *domain, struct intel_iommu *iommu,
+                       u8 bus, u8 devfn)
 {
        struct device_domain_info *info;
 
-       assert_spin_locked(&device_domain_lock);
-
        if (!iommu->qi)
                return NULL;
 
-       list_for_each_entry(info, &domain->devices, link)
+       spin_lock(&device_domain_lock);
+       list_for_each_entry(info, &domain->devices, link) {
                if (info->iommu == iommu && info->bus == bus &&
                    info->devfn == devfn) {
-                       if (info->ats_supported && info->dev)
-                               return info;
-                       break;
+                       spin_unlock(&device_domain_lock);
+                       return info->ats_supported ? info : NULL;
                }
+       }
+       spin_unlock(&device_domain_lock);
 
        return NULL;
 }
@@ -1402,23 +1396,21 @@ static void domain_update_iotlb(struct dmar_domain *domain)
        struct device_domain_info *info;
        bool has_iotlb_device = false;
 
-       assert_spin_locked(&device_domain_lock);
-
-       list_for_each_entry(info, &domain->devices, link)
+       spin_lock(&device_domain_lock);
+       list_for_each_entry(info, &domain->devices, link) {
                if (info->ats_enabled) {
                        has_iotlb_device = true;
                        break;
                }
-
+       }
        domain->has_iotlb_device = has_iotlb_device;
+       spin_unlock(&device_domain_lock);
 }
 
 static void iommu_enable_dev_iotlb(struct device_domain_info *info)
 {
        struct pci_dev *pdev;
 
-       assert_spin_locked(&device_domain_lock);
-
        if (!info || !dev_is_pci(info->dev))
                return;
 
@@ -1464,8 +1456,6 @@ static void iommu_disable_dev_iotlb(struct device_domain_info *info)
 {
        struct pci_dev *pdev;
 
-       assert_spin_locked(&device_domain_lock);
-
        if (!dev_is_pci(info->dev))
                return;
 
@@ -1906,9 +1896,10 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
                                      struct pasid_table *table,
                                      u8 bus, u8 devfn)
 {
+       struct device_domain_info *info =
+                       iommu_support_dev_iotlb(domain, iommu, bus, devfn);
        u16 did = domain->iommu_did[iommu->seq_id];
        int translation = CONTEXT_TT_MULTI_LEVEL;
-       struct device_domain_info *info = NULL;
        struct context_entry *context;
        int ret;
 
@@ -1922,9 +1913,7 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
 
        BUG_ON(!domain->pgd);
 
-       spin_lock(&device_domain_lock);
        spin_lock(&iommu->lock);
-
        ret = -ENOMEM;
        context = iommu_context_addr(iommu, bus, devfn, 1);
        if (!context)
@@ -1975,7 +1964,6 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
                 * Setup the Device-TLB enable bit and Page request
                 * Enable bit:
                 */
-               info = iommu_support_dev_iotlb(domain, iommu, bus, devfn);
                if (info && info->ats_supported)
                        context_set_sm_dte(context);
                if (info && info->pri_supported)
@@ -1998,7 +1986,6 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
                                        goto out_unlock;
                        }
 
-                       info = iommu_support_dev_iotlb(domain, iommu, bus, devfn);
                        if (info && info->ats_supported)
                                translation = CONTEXT_TT_DEV_IOTLB;
                        else
@@ -2044,7 +2031,6 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
 
 out_unlock:
        spin_unlock(&iommu->lock);
-       spin_unlock(&device_domain_lock);
 
        return ret;
 }
@@ -2456,13 +2442,11 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
        if (!iommu)
                return -ENODEV;
 
-       spin_lock(&device_domain_lock);
-       info->domain = domain;
        ret = domain_attach_iommu(domain, iommu);
-       if (ret) {
-               spin_unlock(&device_domain_lock);
+       if (ret)
                return ret;
-       }
+       info->domain = domain;
+       spin_lock(&device_domain_lock);
        list_add(&info->link, &domain->devices);
        spin_unlock(&device_domain_lock);
 
@@ -4638,9 +4622,7 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev)
        if (!domain)
                return -EINVAL;
 
-       spin_lock(&device_domain_lock);
        spin_lock(&iommu->lock);
-
        ret = -EINVAL;
        if (!info->pasid_supported)
                goto out;
@@ -4670,7 +4652,6 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev)
 
  out:
        spin_unlock(&iommu->lock);
-       spin_unlock(&device_domain_lock);
 
        return ret;
 }