iommu/vt-d: Fold __dmar_remove_one_dev_info() into its caller

Fold __dmar_remove_one_dev_info() into dmar_remove_one_dev_info() which
is its only caller. Make the spin lock critical range only cover the
device list change code and remove some unnecessary checks.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20220706025524.2904370-10-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: LuBaolu

drivers/iommu/intel/iommu.c

@@ -295,7 +295,6 @@ static LIST_HEAD(dmar_satc_units);
 static int g_num_of_iommus;
 
 static void dmar_remove_one_dev_info(struct device *dev);
-static void __dmar_remove_one_dev_info(struct device_domain_info *info);
 
 int dmar_disabled = !IS_ENABLED(CONFIG_INTEL_IOMMU_DEFAULT_ON);
 int intel_iommu_sm = IS_ENABLED(CONFIG_INTEL_IOMMU_SCALABLE_MODE_DEFAULT_ON);
@@ -4137,20 +4136,12 @@ static void domain_context_clear(struct device_domain_info *info)
 			       &domain_context_clear_one_cb, info);
 }
 
-static void __dmar_remove_one_dev_info(struct device_domain_info *info)
+static void dmar_remove_one_dev_info(struct device *dev)
 {
-	struct dmar_domain *domain;
-	struct intel_iommu *iommu;
-
-	assert_spin_locked(&device_domain_lock);
-
-	if (WARN_ON(!info))
-		return;
-
-	iommu = info->iommu;
-	domain = info->domain;
+	struct device_domain_info *info = dev_iommu_priv_get(dev);
+	struct intel_iommu *iommu = info->iommu;
 
-	if (info->dev && !dev_is_real_dma_subdevice(info->dev)) {
+	if (!dev_is_real_dma_subdevice(info->dev)) {
 		if (dev_is_pci(info->dev) && sm_supported(iommu))
 			intel_pasid_tear_down_entry(iommu, info->dev,
 					PASID_RID2PASID, false);
@@ -4160,19 +4151,12 @@ static void __dmar_remove_one_dev_info(struct device_domain_info *info)
 		intel_pasid_free_table(info->dev);
 	}
 
-	list_del(&info->link);
-	domain_detach_iommu(domain, iommu);
-}
-
-static void dmar_remove_one_dev_info(struct device *dev)
-{
-	struct device_domain_info *info;
-
 	spin_lock(&device_domain_lock);
-	info = dev_iommu_priv_get(dev);
-	if (info)
-		__dmar_remove_one_dev_info(info);
+	list_del(&info->link);
 	spin_unlock(&device_domain_lock);
+
+	domain_detach_iommu(info->domain, iommu);
+	info->domain = NULL;
 }
 
 static int md_domain_init(struct dmar_domain *domain, int guest_width)