[PATCH v4 06/11] iommu/vt-d: Acquiring lock in domain ID allocation helpers

[Lu Baolu]

The iommu->lock is used to protect the per-IOMMU domain ID resource.
Moving the lock into the ID alloc/free helpers makes the code more
compact. At the same time, the device_domain_lock is irrelevant to
the domain ID resource, remove its assertion as well.

Signed-off-by: Lu Baolu <baolu...@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.t...@intel.com>
---
 drivers/iommu/intel/iommu.c | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 93f01082dce1..7f03576e72d7 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -1779,16 +1779,13 @@ 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);
@@ -1797,7 +1794,8 @@ 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);
@@ -1806,7 +1804,9 @@ 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,
@@ -1814,9 +1814,7 @@ 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];
@@ -1824,6 +1822,7 @@ 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)
@@ -2472,9 +2471,7 @@ static int domain_add_dev_info(struct dmar_domain 
*domain, struct device *dev)
 
        spin_lock(&device_domain_lock);
        info->domain = domain;
-       spin_lock(&iommu->lock);
        ret = domain_attach_iommu(domain, iommu);
-       spin_unlock(&iommu->lock);
        if (ret) {
                spin_unlock(&device_domain_lock);
                return ret;
@@ -4178,10 +4175,7 @@ static void __dmar_remove_one_dev_info(struct 
device_domain_info *info)
        }
 
        list_del(&info->link);
-
-       spin_lock(&iommu->lock);
        domain_detach_iommu(domain, iommu);
-       spin_unlock(&iommu->lock);
 }
 
 static void dmar_remove_one_dev_info(struct device *dev)
-- 
2.25.1

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