iommu/vt-d: Get rid of domain->iommu_lock

When this lock is held the device_domain_lock is also
required to make sure the device_domain_info does not vanish
while in use. So this lock can be removed as it gives no
additional protection.

Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index c8d9bef776da863e72d215393bdbee3de9443a02..0f258f0f5ac02f136017d4b484e8b3c084627793 100644 (file)
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -406,7 +406,6 @@ struct dmar_domain {
        int             iommu_superpage;/* Level of superpages supported:
                                           0 == 4KiB (no superpages), 1 == 2MiB,
                                           2 == 1GiB, 3 == 512GiB, 4 == 1TiB */
-       spinlock_t      iommu_lock;     /* protect iommu set in domain */
        u64             max_addr;       /* maximum mapped address */
 
        struct iommu_domain domain;     /* generic domain data structure for
@@ -476,6 +475,8 @@ static void dmar_remove_one_dev_info(struct dmar_domain *domain,
                                     struct device *dev);
 static void domain_context_clear(struct intel_iommu *iommu,
                                 struct device *dev);
+static void __dmar_remove_one_dev_info(struct dmar_domain *domain,
+                                      struct device *dev);
 static int domain_detach_iommu(struct dmar_domain *domain,
                               struct intel_iommu *iommu);
 
@@ -1404,24 +1405,23 @@ iommu_support_dev_iotlb (struct dmar_domain *domain, struct intel_iommu *iommu,
                         u8 bus, u8 devfn)
 {
        bool found = false;
-       unsigned long flags;
        struct device_domain_info *info;
        struct pci_dev *pdev;
 
+       assert_spin_locked(&device_domain_lock);
+
        if (!ecap_dev_iotlb_support(iommu->ecap))
                return NULL;
 
        if (!iommu->qi)
                return NULL;
 
-       spin_lock_irqsave(&device_domain_lock, flags);
        list_for_each_entry(info, &domain->devices, link)
                if (info->iommu == iommu && info->bus == bus &&
                    info->devfn == devfn) {
                        found = true;
                        break;
                }
-       spin_unlock_irqrestore(&device_domain_lock, flags);
 
        if (!found || !info->dev || !dev_is_pci(info->dev))
                return NULL;
@@ -1616,10 +1616,12 @@ static int iommu_init_domains(struct intel_iommu *iommu)
 static void disable_dmar_iommu(struct intel_iommu *iommu)
 {
        struct device_domain_info *info, *tmp;
+       unsigned long flags;
 
        if (!iommu->domains || !iommu->domain_ids)
                return;
 
+       spin_lock_irqsave(&device_domain_lock, flags);
        list_for_each_entry_safe(info, tmp, &device_domain_list, global) {
                struct dmar_domain *domain;
 
@@ -1636,6 +1638,7 @@ static void disable_dmar_iommu(struct intel_iommu *iommu)
                if (!domain_type_is_vm_or_si(domain))
                        domain_exit(domain);
        }
+       spin_unlock_irqrestore(&device_domain_lock, flags);
 
        if (iommu->gcmd & DMA_GCMD_TE)
                iommu_disable_translation(iommu);
@@ -1672,7 +1675,6 @@ static struct dmar_domain *alloc_domain(int flags)
        memset(domain, 0, sizeof(*domain));
        domain->nid = -1;
        domain->flags = flags;
-       spin_lock_init(&domain->iommu_lock);
        INIT_LIST_HEAD(&domain->devices);
 
        return domain;
@@ -1683,13 +1685,11 @@ static int domain_attach_iommu(struct dmar_domain *domain,
                               struct intel_iommu *iommu)
 {
        unsigned long ndomains;
-       unsigned long flags;
-       int ret, num;
+       int num;
 
+       assert_spin_locked(&device_domain_lock);
        assert_spin_locked(&iommu->lock);
 
-       spin_lock_irqsave(&domain->iommu_lock, flags);
-
        domain->iommu_refcnt[iommu->seq_id] += 1;
        domain->iommu_count += 1;
        if (domain->iommu_refcnt[iommu->seq_id] == 1) {
@@ -1700,8 +1700,7 @@ static int domain_attach_iommu(struct dmar_domain *domain,
                        pr_err("%s: No free domain ids\n", iommu->name);
                        domain->iommu_refcnt[iommu->seq_id] -= 1;
                        domain->iommu_count -= 1;
-                       ret = -ENOSPC;
-                       goto out_unlock;
+                       return -ENOSPC;
                }
 
                set_bit(num, iommu->domain_ids);
@@ -1713,22 +1712,17 @@ static int domain_attach_iommu(struct dmar_domain *domain,
                domain_update_iommu_cap(domain);
        }
 
-       ret = 0;
-out_unlock:
-       spin_unlock_irqrestore(&domain->iommu_lock, flags);
-
-       return ret;
+       return 0;
 }
 
 static int domain_detach_iommu(struct dmar_domain *domain,
                               struct intel_iommu *iommu)
 {
        int num, count = INT_MAX;
-       unsigned long flags;
 
+       assert_spin_locked(&device_domain_lock);
        assert_spin_locked(&iommu->lock);
 
-       spin_lock_irqsave(&domain->iommu_lock, flags);
        domain->iommu_refcnt[iommu->seq_id] -= 1;
        count = --domain->iommu_count;
        if (domain->iommu_refcnt[iommu->seq_id] == 0) {
@@ -1739,7 +1733,6 @@ static int domain_detach_iommu(struct dmar_domain *domain,
                domain_update_iommu_cap(domain);
                domain->iommu_did[iommu->seq_id] = 0;
        }
-       spin_unlock_irqrestore(&domain->iommu_lock, flags);
 
        return count;
 }
@@ -1894,7 +1887,7 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
        struct context_entry *context;
        unsigned long flags;
        struct dma_pte *pgd;
-       int agaw;
+       int ret, agaw;
 
        WARN_ON(did == 0);
 
@@ -1906,16 +1899,17 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
 
        BUG_ON(!domain->pgd);
 
-       spin_lock_irqsave(&iommu->lock, flags);
+       spin_lock_irqsave(&device_domain_lock, flags);
+       spin_lock(&iommu->lock);
+
+       ret = -ENOMEM;
        context = iommu_context_addr(iommu, bus, devfn, 1);
-       spin_unlock_irqrestore(&iommu->lock, flags);
        if (!context)
-               return -ENOMEM;
-       spin_lock_irqsave(&iommu->lock, flags);
-       if (context_present(context)) {
-               spin_unlock_irqrestore(&iommu->lock, flags);
-               return 0;
-       }
+               goto out_unlock;
+
+       ret = 0;
+       if (context_present(context))
+               goto out_unlock;
 
        pgd = domain->pgd;
 
@@ -1928,11 +1922,10 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
         */
        if (translation != CONTEXT_TT_PASS_THROUGH) {
                for (agaw = domain->agaw; agaw != iommu->agaw; agaw--) {
+                       ret = -ENOMEM;
                        pgd = phys_to_virt(dma_pte_addr(pgd));
-                       if (!dma_pte_present(pgd)) {
-                               spin_unlock_irqrestore(&iommu->lock, flags);
-                               return -ENOMEM;
-                       }
+                       if (!dma_pte_present(pgd))
+                               goto out_unlock;
                }
 
                info = iommu_support_dev_iotlb(domain, iommu, bus, devfn);
@@ -1971,7 +1964,12 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
                iommu_flush_write_buffer(iommu);
        }
        iommu_enable_dev_iotlb(info);
-       spin_unlock_irqrestore(&iommu->lock, flags);
+
+       ret = 0;
+
+out_unlock:
+       spin_unlock(&iommu->lock);
+       spin_unlock_irqrestore(&device_domain_lock, flags);
 
        return 0;
 }
@@ -2214,9 +2212,12 @@ static inline void unlink_domain_info(struct device_domain_info *info)
 static void domain_remove_dev_info(struct dmar_domain *domain)
 {
        struct device_domain_info *info, *tmp;
+       unsigned long flags;
 
+       spin_lock_irqsave(&device_domain_lock, flags);
        list_for_each_entry_safe(info, tmp, &domain->devices, link)
-               dmar_remove_one_dev_info(domain, info->dev);
+               __dmar_remove_one_dev_info(domain, info->dev);
+       spin_unlock_irqrestore(&device_domain_lock, flags);
 }
 
 /*
@@ -4539,14 +4540,16 @@ static void domain_context_clear(struct intel_iommu *iommu, struct device *dev)
        pci_for_each_dma_alias(to_pci_dev(dev), &domain_context_clear_one_cb, iommu);
 }
 
-static void dmar_remove_one_dev_info(struct dmar_domain *domain,
-                                    struct device *dev)
+static void __dmar_remove_one_dev_info(struct dmar_domain *domain,
+                                      struct device *dev)
 {
        struct device_domain_info *info;
        struct intel_iommu *iommu;
        unsigned long flags;
        u8 bus, devfn;
 
+       assert_spin_locked(&device_domain_lock);
+
        iommu = device_to_iommu(dev, &bus, &devfn);
        if (!iommu)
                return;
@@ -4556,9 +4559,7 @@ static void dmar_remove_one_dev_info(struct dmar_domain *domain,
        if (WARN_ON(!info))
                return;
 
-       spin_lock_irqsave(&device_domain_lock, flags);
        unlink_domain_info(info);
-       spin_unlock_irqrestore(&device_domain_lock, flags);
 
        iommu_disable_dev_iotlb(info);
        domain_context_clear(iommu, dev);
@@ -4569,6 +4570,16 @@ static void dmar_remove_one_dev_info(struct dmar_domain *domain,
        spin_unlock_irqrestore(&iommu->lock, flags);
 }
 
+static void dmar_remove_one_dev_info(struct dmar_domain *domain,
+                                    struct device *dev)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&device_domain_lock, flags);
+       __dmar_remove_one_dev_info(domain, dev);
+       spin_unlock_irqrestore(&device_domain_lock, flags);
+}
+
 static int md_domain_init(struct dmar_domain *domain, int guest_width)
 {
        int adjust_width;