[Patch Part3 V4 04/21] iommu/vt-d: Introduce helper functions to make code symmetric for readability

Jiang Liu
2014-07-11T06:17:11Z

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>
---
drivers/iommu/intel-iommu.c | 147 +++++++++++++++++++++++--------------------
1 file changed, 80 insertions(+), 67 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 52250b3e58d1..eae9b0d8bc60 100644
--- 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);
}
}

--
1.7.10.4