[v4,12/13] iommu/arm-smmu-v3-sva: Remove arm_smmu_bond
Commit Message
There's a 1:1 relationship between arm_smmu_bond and the iommu_domain
used in set_dev_pasid/remove_dev_pasid. arm_smmu_bond has become an
unnecessary complication. It's more natural to store any needed
information at the iommu_domain container level.
Signed-off-by: Michael Shavit <mshavit@google.com>
---
.../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 69 +++++++------------
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 1 -
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 2 +-
3 files changed, 24 insertions(+), 48 deletions(-)
Comments
> On Wed, Jun 21, 2023 at 2:44 PM Michael Shavit <mshavit@google.com> wrote:
> @@ -545,23 +534,12 @@ void arm_smmu_sva_notifier_synchronize(void)
> void arm_smmu_sva_remove_dev_pasid(struct iommu_domain *domain,
> struct device *dev, ioasid_t id)
> {
> - struct mm_struct *mm = domain->mm;
> - struct arm_smmu_bond *bond = NULL, *t;
> + struct arm_smmu_sva_domain *sva_domain = to_sva_domain(domain);
> struct arm_smmu_master *master = dev_iommu_priv_get(dev);
>
> mutex_lock(&sva_lock);
> - list_for_each_entry(t, &master->bonds, list) {
> - if (t->mm == mm) {
> - bond = t;
> - break;
> - }
> - }
> -
> - if (!WARN_ON(!bond)) {
> - list_del(&bond->list);
> - arm_smmu_mmu_notifier_put(bond->smmu_mn);
> - kfree(bond);
> - }
> + master->nr_attached_sva_domains -= 1;
> + arm_smmu_mmu_notifier_put(sva_domain->smmu_mn);
> mutex_unlock(&sva_lock);
> }
I've encountered a bug with this change while working on a follow-up
series. arm_smmu_sva_remove_dev_pasid() is called on the domain if
arm_smmu_sva_set_dev_pasid failed. Removing the WARN_ON(!bond)
condition removed a protection against that scenario. I have a fix for
this change that I'll push into a v5 of the series.
@@ -24,14 +24,13 @@ struct arm_smmu_mmu_notifier {
#define mn_to_smmu(mn) container_of(mn, struct arm_smmu_mmu_notifier, mn)
-struct arm_smmu_bond {
- struct mm_struct *mm;
+struct arm_smmu_sva_domain {
+ struct iommu_domain iommu_domain;
struct arm_smmu_mmu_notifier *smmu_mn;
- struct list_head list;
};
-#define sva_to_bond(handle) \
- container_of(handle, struct arm_smmu_bond, sva)
+#define to_sva_domain(domain) \
+ container_of(domain, struct arm_smmu_sva_domain, iommu_domain)
static DEFINE_MUTEX(sva_lock);
@@ -363,10 +362,10 @@ static void arm_smmu_mmu_notifier_put(struct arm_smmu_mmu_notifier *smmu_mn)
arm_smmu_free_shared_cd(cd);
}
-static int __arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm)
+static int __arm_smmu_sva_bind(struct device *dev,
+ struct arm_smmu_sva_domain *sva_domain,
+ struct mm_struct *mm)
{
- int ret;
- struct arm_smmu_bond *bond;
struct arm_smmu_master *master = dev_iommu_priv_get(dev);
struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
@@ -374,24 +373,14 @@ static int __arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm)
if (!master || !master->sva_enabled)
return -ENODEV;
- bond = kzalloc(sizeof(*bond), GFP_KERNEL);
- if (!bond)
- return -ENOMEM;
-
- bond->mm = mm;
-
- bond->smmu_mn = arm_smmu_mmu_notifier_get(smmu_domain, mm);
- if (IS_ERR(bond->smmu_mn)) {
- ret = PTR_ERR(bond->smmu_mn);
- goto err_free_bond;
+ sva_domain->smmu_mn = arm_smmu_mmu_notifier_get(smmu_domain,
+ mm);
+ if (IS_ERR(sva_domain->smmu_mn)) {
+ sva_domain->smmu_mn = NULL;
+ return PTR_ERR(sva_domain->smmu_mn);
}
-
- list_add(&bond->list, &master->bonds);
+ master->nr_attached_sva_domains += 1;
return 0;
-
-err_free_bond:
- kfree(bond);
- return ret;
}
bool arm_smmu_sva_supported(struct arm_smmu_device *smmu)
@@ -521,7 +510,7 @@ int arm_smmu_master_enable_sva(struct arm_smmu_master *master)
int arm_smmu_master_disable_sva(struct arm_smmu_master *master)
{
mutex_lock(&sva_lock);
- if (!list_empty(&master->bonds)) {
+ if (master->nr_attached_sva_domains != 0) {
dev_err(master->dev, "cannot disable SVA, device is bound\n");
mutex_unlock(&sva_lock);
return -EBUSY;
@@ -545,23 +534,12 @@ void arm_smmu_sva_notifier_synchronize(void)
void arm_smmu_sva_remove_dev_pasid(struct iommu_domain *domain,
struct device *dev, ioasid_t id)
{
- struct mm_struct *mm = domain->mm;
- struct arm_smmu_bond *bond = NULL, *t;
+ struct arm_smmu_sva_domain *sva_domain = to_sva_domain(domain);
struct arm_smmu_master *master = dev_iommu_priv_get(dev);
mutex_lock(&sva_lock);
- list_for_each_entry(t, &master->bonds, list) {
- if (t->mm == mm) {
- bond = t;
- break;
- }
- }
-
- if (!WARN_ON(!bond)) {
- list_del(&bond->list);
- arm_smmu_mmu_notifier_put(bond->smmu_mn);
- kfree(bond);
- }
+ master->nr_attached_sva_domains -= 1;
+ arm_smmu_mmu_notifier_put(sva_domain->smmu_mn);
mutex_unlock(&sva_lock);
}
@@ -572,7 +550,7 @@ static int arm_smmu_sva_set_dev_pasid(struct iommu_domain *domain,
struct mm_struct *mm = domain->mm;
mutex_lock(&sva_lock);
- ret = __arm_smmu_sva_bind(dev, mm);
+ ret = __arm_smmu_sva_bind(dev, to_sva_domain(domain), mm);
mutex_unlock(&sva_lock);
return ret;
@@ -590,12 +568,11 @@ static const struct iommu_domain_ops arm_smmu_sva_domain_ops = {
struct iommu_domain *arm_smmu_sva_domain_alloc(void)
{
- struct iommu_domain *domain;
+ struct arm_smmu_sva_domain *sva_domain;
- domain = kzalloc(sizeof(*domain), GFP_KERNEL);
- if (!domain)
+ sva_domain = kzalloc(sizeof(*sva_domain), GFP_KERNEL);
+ if (!sva_domain)
return NULL;
- domain->ops = &arm_smmu_sva_domain_ops;
-
- return domain;
+ sva_domain->iommu_domain.ops = &arm_smmu_sva_domain_ops;
+ return &sva_domain->iommu_domain;
}
@@ -2784,7 +2784,6 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev)
master->dev = dev;
master->smmu = smmu;
- INIT_LIST_HEAD(&master->bonds);
dev_iommu_priv_set(dev, master);
ret = arm_smmu_insert_master(smmu, master);
@@ -705,7 +705,7 @@ struct arm_smmu_master {
bool stall_enabled;
bool sva_enabled;
bool iopf_enabled;
- struct list_head bonds;
+ unsigned int nr_attached_sva_domains;
unsigned int ssid_bits;
unsigned int nr_attached_pasid_domains;
};