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iommu/vt-d: Unify domain->iommu attach/detachment
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Move the code to attach/detach domains to iommus and vice
verce into a single function to make sure there are no
dangling references.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
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Joerg Roedel committed Aug 12, 2015
1 parent c6c2ceb commit d160aca
Showing 1 changed file with 49 additions and 76 deletions.
125 changes: 49 additions & 76 deletions drivers/iommu/intel-iommu.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1678,90 +1678,64 @@ static struct dmar_domain *alloc_domain(int flags)
return domain;
}

static int __iommu_attach_domain(struct dmar_domain *domain,
struct intel_iommu *iommu)
{
int num;
unsigned long ndomains;

num = domain->iommu_did[iommu->seq_id];
if (num)
return num;

ndomains = cap_ndoms(iommu->cap);
num = find_first_zero_bit(iommu->domain_ids, ndomains);

if (num < ndomains) {
set_bit(num, iommu->domain_ids);
set_iommu_domain(iommu, num, domain);
domain->iommu_did[iommu->seq_id] = num;
} else {
num = -ENOSPC;
}

if (num < 0)
pr_err("%s: No free domain ids\n", iommu->name);

return num;
}

static int iommu_attach_domain(struct dmar_domain *domain,
/* Must be called with iommu->lock */
static int domain_attach_iommu(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);
spin_unlock_irqrestore(&iommu->lock, flags);

return num;
}

static void iommu_detach_domain(struct dmar_domain *domain,
struct intel_iommu *iommu)
{
unsigned long ndomains;
unsigned long flags;
int num;

spin_lock_irqsave(&iommu->lock, flags);
int ret, num;

num = domain->iommu_did[iommu->seq_id];

if (num == 0)
return;

clear_bit(num, iommu->domain_ids);
set_iommu_domain(iommu, num, NULL);

spin_unlock_irqrestore(&iommu->lock, flags);
}

static void domain_attach_iommu(struct dmar_domain *domain,
struct intel_iommu *iommu)
{
unsigned long flags;
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) {
domain->nid = iommu->node;
ndomains = cap_ndoms(iommu->cap);
num = find_first_zero_bit(iommu->domain_ids, ndomains);

if (num >= ndomains) {
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;
}

set_bit(num, iommu->domain_ids);
set_iommu_domain(iommu, num, domain);

domain->iommu_did[iommu->seq_id] = num;
domain->nid = iommu->node;

domain_update_iommu_cap(domain);
}

ret = 0;
out_unlock:
spin_unlock_irqrestore(&domain->iommu_lock, flags);

return ret;
}

static int domain_detach_iommu(struct dmar_domain *domain,
struct intel_iommu *iommu)
{
int num, count = INT_MAX;
unsigned long flags;
int count = INT_MAX;

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) {
num = domain->iommu_did[iommu->seq_id];
clear_bit(num, iommu->domain_ids);
set_iommu_domain(iommu, num, NULL);

domain_update_iommu_cap(domain);
domain->iommu_did[iommu->seq_id] = 0;
}
Expand Down Expand Up @@ -1886,7 +1860,6 @@ static int domain_init(struct dmar_domain *domain, struct intel_iommu *iommu,
static void domain_exit(struct dmar_domain *domain)
{
struct page *freelist = NULL;
int i;

/* Domain 0 is reserved, so dont process it */
if (!domain)
Expand All @@ -1896,20 +1869,16 @@ static void domain_exit(struct dmar_domain *domain)
if (!intel_iommu_strict)
flush_unmaps_timeout(0);

/* remove associated devices */
/* Remove associated devices and clear attached or cached domains */
rcu_read_lock();
domain_remove_dev_info(domain);
rcu_read_unlock();

/* destroy iovas */
put_iova_domain(&domain->iovad);

freelist = domain_unmap(domain, 0, DOMAIN_MAX_PFN(domain->gaw));

/* clear attached or cached domains */
rcu_read_lock();
for_each_domain_iommu(i, domain)
iommu_detach_domain(domain, g_iommus[i]);
rcu_read_unlock();

dma_free_pagelist(freelist);

free_domain_mem(domain);
Expand Down Expand Up @@ -2286,6 +2255,7 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
struct dmar_domain *found = NULL;
struct device_domain_info *info;
unsigned long flags;
int ret;

info = alloc_devinfo_mem();
if (!info)
Expand Down Expand Up @@ -2313,11 +2283,14 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
return found;
}

if (iommu_attach_domain(domain, iommu) < 0) {
spin_lock(&iommu->lock);
ret = domain_attach_iommu(domain, iommu);
spin_unlock(&iommu->lock);

if (ret) {
spin_unlock_irqrestore(&device_domain_lock, flags);
return NULL;
}
domain_attach_iommu(domain, iommu);

list_add(&info->link, &domain->devices);
list_add(&info->global, &device_domain_list);
Expand Down Expand Up @@ -4590,12 +4563,10 @@ static void dmar_remove_one_dev_info(struct dmar_domain *domain,
iommu_disable_dev_iotlb(info);
domain_context_clear(iommu, dev);
free_devinfo_mem(info);
domain_detach_iommu(domain, iommu);

spin_lock_irqsave(&domain->iommu_lock, flags);
if (!domain->iommu_refcnt[iommu->seq_id])
iommu_detach_domain(domain, iommu);
spin_unlock_irqrestore(&domain->iommu_lock, flags);
spin_lock_irqsave(&iommu->lock, flags);
domain_detach_iommu(domain, iommu);
spin_unlock_irqrestore(&iommu->lock, flags);
}

static int md_domain_init(struct dmar_domain *domain, int guest_width)
Expand Down Expand Up @@ -4676,10 +4647,12 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,

old_domain = find_domain(dev);
if (old_domain) {
rcu_read_lock();
if (domain_type_is_vm_or_si(dmar_domain))
dmar_remove_one_dev_info(old_domain, dev);
else
domain_remove_dev_info(old_domain);
rcu_read_unlock();

if (!domain_type_is_vm_or_si(old_domain) &&
list_empty(&old_domain->devices))
Expand Down

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