[PATCH 11/12] iommu/vt-d: Use device_domain_lock accurately
From: Lu Baolu
Date: Fri May 27 2022 - 02:35:36 EST
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@xxxxxxxxxxxxxxx>
---
drivers/iommu/intel/iommu.c | 68 +++++++++++++++----------------------
1 file changed, 27 insertions(+), 41 deletions(-)
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index d02ddd338afd..f8aa8649dc6f 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -534,16 +534,10 @@ static int domain_update_device_node(struct dmar_domain *domain)
{
struct device_domain_info *info;
int nid = NUMA_NO_NODE;
+ unsigned long flags;
- assert_spin_locked(&device_domain_lock);
-
- if (list_empty(&domain->devices))
- return NUMA_NO_NODE;
-
+ spin_lock_irqsave(&device_domain_lock, flags);
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 +548,7 @@ static int domain_update_device_node(struct dmar_domain *domain)
if (nid != NUMA_NO_NODE)
break;
}
+ spin_unlock_irqrestore(&device_domain_lock, flags);
return nid;
}
@@ -1376,49 +1371,50 @@ 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);
+ struct device_domain_info *info = NULL, *tmp;
+ unsigned long flags;
if (!iommu->qi)
return NULL;
- 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;
+ spin_lock_irqsave(&device_domain_lock, flags);
+ list_for_each_entry(tmp, &domain->devices, link) {
+ if (tmp->iommu == iommu && tmp->bus == bus &&
+ tmp->devfn == devfn) {
+ if (tmp->ats_supported)
+ info = tmp;
break;
}
+ }
+ spin_unlock_irqrestore(&device_domain_lock, flags);
- return NULL;
+ return info;
}
static void domain_update_iotlb(struct dmar_domain *domain)
{
struct device_domain_info *info;
bool has_iotlb_device = false;
+ unsigned long flags;
- assert_spin_locked(&device_domain_lock);
-
- list_for_each_entry(info, &domain->devices, link)
+ spin_lock_irqsave(&device_domain_lock, flags);
+ 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_irqrestore(&device_domain_lock, flags);
}
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 +1460,6 @@ 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;
@@ -1900,11 +1894,11 @@ 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;
- unsigned long flags;
int ret;
WARN_ON(did == 0);
@@ -1917,7 +1911,6 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
BUG_ON(!domain->pgd);
- spin_lock_irqsave(&device_domain_lock, flags);
spin_lock(&iommu->lock);
ret = -ENOMEM;
@@ -1970,7 +1963,6 @@ 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)
@@ -1993,7 +1985,6 @@ 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
@@ -2039,7 +2030,6 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
out_unlock:
spin_unlock(&iommu->lock);
- spin_unlock_irqrestore(&device_domain_lock, flags);
return ret;
}
@@ -2452,15 +2442,14 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
if (!iommu)
return -ENODEV;
- spin_lock_irqsave(&device_domain_lock, flags);
- info->domain = domain;
ret = domain_attach_iommu(domain, iommu);
- if (ret) {
- spin_unlock_irqrestore(&device_domain_lock, flags);
+ if (ret)
return ret;
- }
+
+ spin_lock_irqsave(&device_domain_lock, flags);
list_add(&info->link, &domain->devices);
spin_unlock_irqrestore(&device_domain_lock, flags);
+ info->domain = domain;
/* PASID table is mandatory for a PCI device in scalable mode. */
if (sm_supported(iommu) && !dev_is_real_dma_subdevice(dev)) {
@@ -4629,7 +4618,6 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev)
struct device_domain_info *info = dev_iommu_priv_get(dev);
struct context_entry *context;
struct dmar_domain *domain;
- unsigned long flags;
u64 ctx_lo;
int ret;
@@ -4637,7 +4625,6 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev)
if (!domain)
return -EINVAL;
- spin_lock_irqsave(&device_domain_lock, flags);
spin_lock(&iommu->lock);
ret = -EINVAL;
@@ -4669,7 +4656,6 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev)
out:
spin_unlock(&iommu->lock);
- spin_unlock_irqrestore(&device_domain_lock, flags);
return ret;
}
--
2.25.1