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

Tian, Kevin
2020-07-06T01:10:15Z

> From: Lu Baolu <baolu.lu@linux.intel.com>
> Sent: Monday, July 6, 2020 8:26 AM
>
> 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

Reviewed-by: Kevin Tian <kevin.tian@intel.com>