iommu/vt-d: Introduce helper functions to make code symmetric for readability

Introduce domain_attach_iommu()/domain_detach_iommu() and refine
iommu_attach_domain()/iommu_detach_domain() to make code symmetric
and improve readability.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 52250b3e58d171b90200818432ade6ba4404a415..eae9b0d8bc60cf6ea833a3396d36142f8f82161d 100644 (file)
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1523,32 +1523,39 @@ static struct dmar_domain *alloc_domain(int flags)
        return domain;
 }
 
-static int iommu_attach_domain(struct dmar_domain *domain,
-                              struct intel_iommu *iommu)
+static int __iommu_attach_domain(struct dmar_domain *domain,
+                                struct intel_iommu *iommu)
 {
        int num;
        unsigned long ndomains;
-       unsigned long flags;
 
        ndomains = cap_ndoms(iommu->cap);
-
-       spin_lock_irqsave(&iommu->lock, flags);
-
        num = find_first_zero_bit(iommu->domain_ids, ndomains);
-       if (num >= ndomains) {
-               spin_unlock_irqrestore(&iommu->lock, flags);
-               printk(KERN_ERR "IOMMU: no free domain ids\n");
-               return -ENOMEM;
+       if (num < ndomains) {
+               set_bit(num, iommu->domain_ids);
+               iommu->domains[num] = domain;
+       } else {
+               num = -ENOSPC;
        }
 
-       domain->id = num;
-       domain->iommu_count++;
-       set_bit(num, iommu->domain_ids);
-       set_bit(iommu->seq_id, domain->iommu_bmp);
-       iommu->domains[num] = domain;
+       return num;
+}
+
+static int iommu_attach_domain(struct dmar_domain *domain,
+                              struct intel_iommu *iommu)
+{
+       int num;
+       unsigned long flags;
+
+       spin_lock_irqsave(&iommu->lock, flags);
+       num = __iommu_attach_domain(domain, iommu);
+       if (num < 0)
+               pr_err("IOMMU: no free domain ids\n");
+       else
+               domain->id = num;
        spin_unlock_irqrestore(&iommu->lock, flags);
 
-       return 0;
+       return num;
 }
 
 static void iommu_detach_domain(struct dmar_domain *domain,
@@ -1558,17 +1565,53 @@ static void iommu_detach_domain(struct dmar_domain *domain,
        int num, ndomains;
 
        spin_lock_irqsave(&iommu->lock, flags);
-       ndomains = cap_ndoms(iommu->cap);
-       for_each_set_bit(num, iommu->domain_ids, ndomains) {
-               if (iommu->domains[num] == domain) {
-                       clear_bit(num, iommu->domain_ids);
-                       iommu->domains[num] = NULL;
-                       break;
+       if (domain_type_is_vm_or_si(domain)) {
+               ndomains = cap_ndoms(iommu->cap);
+               for_each_set_bit(num, iommu->domain_ids, ndomains) {
+                       if (iommu->domains[num] == domain) {
+                               clear_bit(num, iommu->domain_ids);
+                               iommu->domains[num] = NULL;
+                               break;
+                       }
                }
+       } else {
+               clear_bit(domain->id, iommu->domain_ids);
+               iommu->domains[domain->id] = NULL;
        }
        spin_unlock_irqrestore(&iommu->lock, flags);
 }
 
+static void domain_attach_iommu(struct dmar_domain *domain,
+                              struct intel_iommu *iommu)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&domain->iommu_lock, flags);
+       if (!test_and_set_bit(iommu->seq_id, domain->iommu_bmp)) {
+               domain->iommu_count++;
+               if (domain->iommu_count == 1)
+                       domain->nid = iommu->node;
+               domain_update_iommu_cap(domain);
+       }
+       spin_unlock_irqrestore(&domain->iommu_lock, flags);
+}
+
+static int domain_detach_iommu(struct dmar_domain *domain,
+                              struct intel_iommu *iommu)
+{
+       unsigned long flags;
+       int count = INT_MAX;
+
+       spin_lock_irqsave(&domain->iommu_lock, flags);
+       if (test_and_clear_bit(iommu->seq_id, domain->iommu_bmp)) {
+               count = --domain->iommu_count;
+               domain_update_iommu_cap(domain);
+       }
+       spin_unlock_irqrestore(&domain->iommu_lock, flags);
+
+       return count;
+}
+
 static struct iova_domain reserved_iova_list;
 static struct lock_class_key reserved_rbtree_key;
 
@@ -1706,9 +1749,7 @@ static void domain_exit(struct dmar_domain *domain)
        /* clear attached or cached domains */
        rcu_read_lock();
        for_each_active_iommu(iommu, drhd)
-               if (domain_type_is_vm(domain) ||
-                   test_bit(iommu->seq_id, domain->iommu_bmp))
-                       iommu_detach_domain(domain, iommu);
+               iommu_detach_domain(domain, iommu);
        rcu_read_unlock();
 
        dma_free_pagelist(freelist);
@@ -1762,16 +1803,12 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
                }
 
                if (found == 0) {
-                       num = find_first_zero_bit(iommu->domain_ids, ndomains);
-                       if (num >= ndomains) {
+                       id = __iommu_attach_domain(domain, iommu);
+                       if (id < 0) {
                                spin_unlock_irqrestore(&iommu->lock, flags);
-                               printk(KERN_ERR "IOMMU: no free domain ids\n");
+                               pr_err("IOMMU: no free domain ids\n");
                                return -EFAULT;
                        }
-
-                       set_bit(num, iommu->domain_ids);
-                       iommu->domains[num] = domain;
-                       id = num;
                }
 
                /* Skip top levels of page tables for
@@ -1830,14 +1867,8 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
        iommu_enable_dev_iotlb(info);
        spin_unlock_irqrestore(&iommu->lock, flags);
 
-       spin_lock_irqsave(&domain->iommu_lock, flags);
-       if (!test_and_set_bit(iommu->seq_id, domain->iommu_bmp)) {
-               domain->iommu_count++;
-               if (domain->iommu_count == 1)
-                       domain->nid = iommu->node;
-               domain_update_iommu_cap(domain);
-       }
-       spin_unlock_irqrestore(&domain->iommu_lock, flags);
+       domain_attach_iommu(domain, iommu);
+
        return 0;
 }
 
@@ -2085,7 +2116,7 @@ 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, flags2;
+       unsigned long flags;
 
        spin_lock_irqsave(&device_domain_lock, flags);
        list_for_each_entry_safe(info, tmp, &domain->devices, link) {
@@ -2097,16 +2128,7 @@ static void domain_remove_dev_info(struct dmar_domain *domain)
 
                if (domain_type_is_vm(domain)) {
                        iommu_detach_dependent_devices(info->iommu, info->dev);
-                       /* clear this iommu in iommu_bmp, update iommu count
-                        * and capabilities
-                        */
-                       spin_lock_irqsave(&domain->iommu_lock, flags2);
-                       if (test_and_clear_bit(info->iommu->seq_id,
-                                              domain->iommu_bmp)) {
-                               domain->iommu_count--;
-                               domain_update_iommu_cap(domain);
-                       }
-                       spin_unlock_irqrestore(&domain->iommu_lock, flags2);
+                       domain_detach_iommu(domain, info->iommu);
                }
 
                free_devinfo_mem(info);
@@ -2236,11 +2258,11 @@ static struct dmar_domain *get_domain_for_dev(struct device *dev, int gaw)
        if (!domain)
                return NULL;
 
-       if (iommu_attach_domain(domain, iommu)) {
+       if (iommu_attach_domain(domain, iommu) < 0) {
                free_domain_mem(domain);
                return NULL;
        }
-
+       domain_attach_iommu(domain, iommu);
        if (domain_init(domain, gaw)) {
                domain_exit(domain);
                return NULL;
@@ -2413,10 +2435,11 @@ static int __init si_domain_init(int hw)
 
        for_each_active_iommu(iommu, drhd) {
                ret = iommu_attach_domain(si_domain, iommu);
-               if (ret) {
+               if (ret < 0) {
                        domain_exit(si_domain);
                        return -EFAULT;
                }
+               domain_attach_iommu(si_domain, iommu);
        }
 
        if (md_domain_init(si_domain, DEFAULT_DOMAIN_ADDRESS_WIDTH)) {
@@ -4155,19 +4178,9 @@ static void domain_remove_one_dev_info(struct dmar_domain *domain,
        spin_unlock_irqrestore(&device_domain_lock, flags);
 
        if (found == 0) {
-               unsigned long tmp_flags;
-               spin_lock_irqsave(&domain->iommu_lock, tmp_flags);
-               clear_bit(iommu->seq_id, domain->iommu_bmp);
-               domain->iommu_count--;
-               domain_update_iommu_cap(domain);
-               spin_unlock_irqrestore(&domain->iommu_lock, tmp_flags);
-
-               if (!domain_type_is_vm_or_si(domain)) {
-                       spin_lock_irqsave(&iommu->lock, tmp_flags);
-                       clear_bit(domain->id, iommu->domain_ids);
-                       iommu->domains[domain->id] = NULL;
-                       spin_unlock_irqrestore(&iommu->lock, tmp_flags);
-               }
+               domain_detach_iommu(domain, iommu);
+               if (!domain_type_is_vm_or_si(domain))
+                       iommu_detach_domain(domain, iommu);
        }
 }