[PATCH 06/12] iommu/vt-d: Acquiring lock in domain ID allocation helpers

Lu Baolu
2022-05-27T06:34:18Z

The iommu->lock is used to protect the per-IOMMU domain ID resource.
Move the spinlock acquisition/release into the helpers where domain
IDs are allocated and freed. The device_domain_lock is irrelevant to
domain ID resources, remove its assertion as well.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/intel/iommu.c | 25 +++++++++----------------
1 file changed, 9 insertions(+), 16 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 2d5f02b85de8..0da937ce0534 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -1774,16 +1774,13 @@ static struct dmar_domain *alloc_domain(unsigned int type)
return domain;
}

-/* Must be called with iommu->lock */
static int domain_attach_iommu(struct dmar_domain *domain,
struct intel_iommu *iommu)
{
unsigned long ndomains;
- int num;
-
- assert_spin_locked(&device_domain_lock);
- assert_spin_locked(&iommu->lock);
+ int num, ret = 0;

+ spin_lock(&iommu->lock);
domain->iommu_refcnt[iommu->seq_id] += 1;
if (domain->iommu_refcnt[iommu->seq_id] == 1) {
ndomains = cap_ndoms(iommu->cap);
@@ -1792,7 +1789,8 @@ static int domain_attach_iommu(struct dmar_domain *domain,
if (num >= ndomains) {
pr_err("%s: No free domain ids\n", iommu->name);
domain->iommu_refcnt[iommu->seq_id] -= 1;
- return -ENOSPC;
+ ret = -ENOSPC;
+ goto out_unlock;
}

set_bit(num, iommu->domain_ids);
@@ -1801,7 +1799,9 @@ static int domain_attach_iommu(struct dmar_domain *domain,
domain_update_iommu_cap(domain);
}

- return 0;
+out_unlock:
+ spin_unlock(&iommu->lock);
+ return ret;
}

static void domain_detach_iommu(struct dmar_domain *domain,
@@ -1809,9 +1809,7 @@ static void domain_detach_iommu(struct dmar_domain *domain,
{
int num;

- assert_spin_locked(&device_domain_lock);
- assert_spin_locked(&iommu->lock);
-
+ spin_lock(&iommu->lock);
domain->iommu_refcnt[iommu->seq_id] -= 1;
if (domain->iommu_refcnt[iommu->seq_id] == 0) {
num = domain->iommu_did[iommu->seq_id];
@@ -1819,6 +1817,7 @@ static void domain_detach_iommu(struct dmar_domain *domain,
domain_update_iommu_cap(domain);
domain->iommu_did[iommu->seq_id] = 0;
}
+ spin_unlock(&iommu->lock);
}

static inline int guestwidth_to_adjustwidth(int gaw)
@@ -2471,9 +2470,7 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)

spin_lock_irqsave(&device_domain_lock, flags);
info->domain = domain;
- spin_lock(&iommu->lock);
ret = domain_attach_iommu(domain, iommu);
- spin_unlock(&iommu->lock);
if (ret) {
spin_unlock_irqrestore(&device_domain_lock, flags);
return ret;
@@ -4158,7 +4155,6 @@ static void __dmar_remove_one_dev_info(struct device_domain_info *info)
{
struct dmar_domain *domain;
struct intel_iommu *iommu;
- unsigned long flags;

assert_spin_locked(&device_domain_lock);

@@ -4179,10 +4175,7 @@ static void __dmar_remove_one_dev_info(struct device_domain_info *info)
}

list_del(&info->link);
-
- spin_lock_irqsave(&iommu->lock, flags);
domain_detach_iommu(domain, iommu);
- spin_unlock_irqrestore(&iommu->lock, flags);
}

static void dmar_remove_one_dev_info(struct device *dev)
--
2.25.1