[PATCH v2 2/4] iommu/vt-d: Add a helper to get svm and sdev for pasid

Lu Baolu
2020-07-06T00:30:17Z

There are several places in the code that need to get the pointers of
svm and sdev according to a pasid and device. Add a helper to achieve
this for code consolidation and readability.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/intel/svm.c | 121 +++++++++++++++++++++-----------------
1 file changed, 68 insertions(+), 53 deletions(-)

diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 25dd74f27252..c23167877b2b 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -228,6 +228,50 @@ static LIST_HEAD(global_svm_list);
list_for_each_entry((sdev), &(svm)->devs, list) \
if ((d) != (sdev)->dev) {} else

+static int pasid_to_svm_sdev(struct device *dev, unsigned int pasid,
+ struct intel_svm **rsvm,
+ struct intel_svm_dev **rsdev)
+{
+ struct intel_svm_dev *d, *sdev = NULL;
+ struct intel_svm *svm;
+
+ /* The caller should hold the pasid_mutex lock */
+ if (WARN_ON(!mutex_is_locked(&pasid_mutex)))
+ return -EINVAL;
+
+ if (pasid == INVALID_IOASID || pasid >= PASID_MAX)
+ return -EINVAL;
+
+ svm = ioasid_find(NULL, pasid, NULL);
+ if (IS_ERR(svm))
+ return PTR_ERR(svm);
+
+ if (!svm)
+ goto out;
+
+ /*
+ * If we found svm for the PASID, there must be at least one device
+ * bond.
+ */
+ if (WARN_ON(list_empty(&svm->devs)))
+ return -EINVAL;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(d, &svm->devs, list) {
+ if (d->dev == dev) {
+ sdev = d;
+ break;
+ }
+ }
+ rcu_read_unlock();
+
+out:
+ *rsvm = svm;
+ *rsdev = sdev;
+
+ return 0;
+}
+
int intel_svm_bind_gpasid(struct iommu_domain *domain, struct device *dev,
struct iommu_gpasid_bind_data *data)
{
@@ -261,39 +305,27 @@ int intel_svm_bind_gpasid(struct iommu_domain *domain, struct device *dev,
dmar_domain = to_dmar_domain(domain);

mutex_lock(&pasid_mutex);
- svm = ioasid_find(NULL, data->hpasid, NULL);
- if (IS_ERR(svm)) {
- ret = PTR_ERR(svm);
+ ret = pasid_to_svm_sdev(dev, data->hpasid, &svm, &sdev);
+ if (ret)
goto out;
- }

- if (svm) {
+ if (sdev) {
/*
- * If we found svm for the PASID, there must be at
- * least one device bond, otherwise svm should be freed.
+ * For devices with aux domains, we should allow
+ * multiple bind calls with the same PASID and pdev.
*/
- if (WARN_ON(list_empty(&svm->devs))) {
- ret = -EINVAL;
- goto out;
+ if (iommu_dev_feature_enabled(dev, IOMMU_DEV_FEAT_AUX)) {
+ sdev->users++;
+ } else {
+ dev_warn_ratelimited(dev,
+ "Already bound with PASID %u\n",
+ svm->pasid);
+ ret = -EBUSY;
}
+ goto out;
+ }

- for_each_svm_dev(sdev, svm, dev) {
- /*
- * For devices with aux domains, we should allow
- * multiple bind calls with the same PASID and pdev.
- */
- if (iommu_dev_feature_enabled(dev,
- IOMMU_DEV_FEAT_AUX)) {
- sdev->users++;
- } else {
- dev_warn_ratelimited(dev,
- "Already bound with PASID %u\n",
- svm->pasid);
- ret = -EBUSY;
- }
- goto out;
- }
- } else {
+ if (!svm) {
/* We come here when PASID has never been bond to a device. */
svm = kzalloc(sizeof(*svm), GFP_KERNEL);
if (!svm) {
@@ -376,25 +408,17 @@ int intel_svm_unbind_gpasid(struct device *dev, int pasid)
struct intel_iommu *iommu = device_to_iommu(dev, NULL, NULL);
struct intel_svm_dev *sdev;
struct intel_svm *svm;
- int ret = -EINVAL;
+ int ret;

if (WARN_ON(!iommu))
return -EINVAL;

mutex_lock(&pasid_mutex);
- svm = ioasid_find(NULL, pasid, NULL);
- if (!svm) {
- ret = -EINVAL;
- goto out;
- }
-
- if (IS_ERR(svm)) {
- ret = PTR_ERR(svm);
+ ret = pasid_to_svm_sdev(dev, pasid, &svm, &sdev);
+ if (ret)
goto out;
- }

- for_each_svm_dev(sdev, svm, dev) {
- ret = 0;
+ if (sdev) {
if (iommu_dev_feature_enabled(dev, IOMMU_DEV_FEAT_AUX))
sdev->users--;
if (!sdev->users) {
@@ -418,7 +442,6 @@ int intel_svm_unbind_gpasid(struct device *dev, int pasid)
kfree(svm);
}
}
- break;
}
out:
mutex_unlock(&pasid_mutex);
@@ -596,7 +619,7 @@ intel_svm_bind_mm(struct device *dev, int flags, struct svm_dev_ops *ops,
if (sd)
*sd = sdev;
ret = 0;
- out:
+out:
return ret;
}

@@ -612,17 +635,11 @@ static int intel_svm_unbind_mm(struct device *dev, int pasid)
if (!iommu)
goto out;

- svm = ioasid_find(NULL, pasid, NULL);
- if (!svm)
- goto out;
-
- if (IS_ERR(svm)) {
- ret = PTR_ERR(svm);
+ ret = pasid_to_svm_sdev(dev, pasid, &svm, &sdev);
+ if (ret)
goto out;
- }

- for_each_svm_dev(sdev, svm, dev) {
- ret = 0;
+ if (sdev) {
sdev->users--;
if (!sdev->users) {
list_del_rcu(&sdev->list);
@@ -651,10 +668,8 @@ static int intel_svm_unbind_mm(struct device *dev, int pasid)
kfree(svm);
}
}
- break;
}
- out:
-
+out:
return ret;
}

--
2.17.1