linux-kernel - [PATCH v4 6/7] iommu/vt-d: Remove unnecessary domain_context

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Date:   Fri, 18 Nov 2022 21:24:50 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     iommu@...ts.linux.dev
Cc:     Joerg Roedel <joro@...tes.org>, Kevin Tian <kevin.tian@...el.com>,
        Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        Liu Yi L <yi.l.liu@...el.com>,
        Jacob jun Pan <jacob.jun.pan@...el.com>,
        linux-kernel@...r.kernel.org, Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH v4 6/7] iommu/vt-d: Remove unnecessary domain_context_mapped()

The device_domain_info::domain accurately records the domain attached to
the device. It is unnecessary to check whether the context is present in
the attach_dev path. Remove it to make the code neat.

Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@...el.com>
---
 drivers/iommu/intel/iommu.c | 47 +++----------------------------------
 1 file changed, 3 insertions(+), 44 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 3bd79ae238f2..3b37f1b3b6de 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -780,19 +780,6 @@ static void domain_flush_cache(struct dmar_domain *domain,
 		clflush_cache_range(addr, size);
 }
 
-static int device_context_mapped(struct intel_iommu *iommu, u8 bus, u8 devfn)
-{
-	struct context_entry *context;
-	int ret = 0;
-
-	spin_lock(&iommu->lock);
-	context = iommu_context_addr(iommu, bus, devfn, 0);
-	if (context)
-		ret = context_present(context);
-	spin_unlock(&iommu->lock);
-	return ret;
-}
-
 static void free_context_table(struct intel_iommu *iommu)
 {
 	struct context_entry *context;
@@ -2097,30 +2084,6 @@ domain_context_mapping(struct dmar_domain *domain, struct device *dev)
 				      &domain_context_mapping_cb, &data);
 }
 
-static int domain_context_mapped_cb(struct pci_dev *pdev,
-				    u16 alias, void *opaque)
-{
-	struct intel_iommu *iommu = opaque;
-
-	return !device_context_mapped(iommu, PCI_BUS_NUM(alias), alias & 0xff);
-}
-
-static int domain_context_mapped(struct device *dev)
-{
-	struct intel_iommu *iommu;
-	u8 bus, devfn;
-
-	iommu = device_to_iommu(dev, &bus, &devfn);
-	if (!iommu)
-		return -ENODEV;
-
-	if (!dev_is_pci(dev))
-		return device_context_mapped(iommu, bus, devfn);
-
-	return !pci_for_each_dma_alias(to_pci_dev(dev),
-				       domain_context_mapped_cb, iommu);
-}
-
 /* Returns a number of VTD pages, but aligned to MM page size */
 static inline unsigned long aligned_nrpages(unsigned long host_addr,
 					    size_t size)
@@ -4269,6 +4232,7 @@ static int prepare_domain_attach_device(struct iommu_domain *domain,
 static int intel_iommu_attach_device(struct iommu_domain *domain,
 				     struct device *dev)
 {
+	struct device_domain_info *info = dev_iommu_priv_get(dev);
 	int ret;
 
 	if (domain->type == IOMMU_DOMAIN_UNMANAGED &&
@@ -4277,13 +4241,8 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
 		return -EPERM;
 	}
 
-	/* normally dev is not mapped */
-	if (unlikely(domain_context_mapped(dev))) {
-		struct device_domain_info *info = dev_iommu_priv_get(dev);
-
-		if (info->domain)
-			device_block_translation(dev);
-	}
+	if (info->domain)
+		device_block_translation(dev);
 
 	ret = prepare_domain_attach_device(domain, dev);
 	if (ret)
-- 
2.34.1