[PATCH v4 7/9] iommu: Use right way to retrieve iommu_ops

Lu Baolu
2022-02-16T02:55:08Z

The common iommu_ops is hooked to both device and domain. When a helper
has both device and domain pointer, the way to get the iommu_ops looks
messy in iommu core. This sorts out the way to get iommu_ops. The device
related helpers go through device pointer, while the domain related ones
go through domain pointer.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
---
include/linux/iommu.h | 11 ++++++++++
drivers/iommu/iommu.c | 50 +++++++++++++++++++++----------------------
2 files changed, 36 insertions(+), 25 deletions(-)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 9ffa2e88f3d0..90f1b5e3809d 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -381,6 +381,17 @@ static inline void iommu_iotlb_gather_init(struct iommu_iotlb_gather *gather)
};
}

+static inline const struct iommu_ops *dev_iommu_ops(struct device *dev)
+{
+ /*
+ * Assume that valid ops must be installed if iommu_probe_device()
+ * has succeeded. The device ops are essentially for internal use
+ * within the IOMMU subsystem itself, so we should be able to trust
+ * ourselves not to misuse the helper.
+ */
+ return dev->iommu->iommu_dev->ops;
+}
+
#define IOMMU_GROUP_NOTIFY_ADD_DEVICE 1 /* Device added */
#define IOMMU_GROUP_NOTIFY_DEL_DEVICE 2 /* Pre Device removed */
#define IOMMU_GROUP_NOTIFY_BIND_DRIVER 3 /* Pre Driver bind */
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 7cf073c56036..7af0ee670deb 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -323,13 +323,14 @@ int iommu_probe_device(struct device *dev)

void iommu_release_device(struct device *dev)
{
- const struct iommu_ops *ops = dev->bus->iommu_ops;
+ const struct iommu_ops *ops;

if (!dev->iommu)
return;

iommu_device_unlink(dev->iommu->iommu_dev, dev);

+ ops = dev_iommu_ops(dev);
ops->release_device(dev);

iommu_group_remove_device(dev);
@@ -833,8 +834,10 @@ static int iommu_create_device_direct_mappings(struct iommu_group *group,
static bool iommu_is_attach_deferred(struct iommu_domain *domain,
struct device *dev)
{
- if (domain->ops->is_attach_deferred)
- return domain->ops->is_attach_deferred(domain, dev);
+ const struct iommu_ops *ops = dev_iommu_ops(dev);
+
+ if (ops->is_attach_deferred)
+ return ops->is_attach_deferred(domain, dev);

return false;
}
@@ -1252,10 +1255,10 @@ int iommu_page_response(struct device *dev,
struct iommu_fault_event *evt;
struct iommu_fault_page_request *prm;
struct dev_iommu *param = dev->iommu;
+ const struct iommu_ops *ops = dev_iommu_ops(dev);
bool has_pasid = msg->flags & IOMMU_PAGE_RESP_PASID_VALID;
- struct iommu_domain *domain = iommu_get_domain_for_dev(dev);

- if (!domain || !domain->ops->page_response)
+ if (!ops->page_response)
return -ENODEV;

if (!param || !param->fault_param)
@@ -1296,7 +1299,7 @@ int iommu_page_response(struct device *dev,
msg->pasid = 0;
}

- ret = domain->ops->page_response(dev, evt, msg);
+ ret = ops->page_response(dev, evt, msg);
list_del(&evt->list);
kfree(evt);
break;
@@ -1521,7 +1524,7 @@ EXPORT_SYMBOL_GPL(fsl_mc_device_group);

static int iommu_get_def_domain_type(struct device *dev)
{
- const struct iommu_ops *ops = dev->bus->iommu_ops;
+ const struct iommu_ops *ops = dev_iommu_ops(dev);

if (dev_is_pci(dev) && to_pci_dev(dev)->untrusted)
return IOMMU_DOMAIN_DMA;
@@ -1580,7 +1583,7 @@ static int iommu_alloc_default_domain(struct iommu_group *group,
*/
static struct iommu_group *iommu_group_get_for_dev(struct device *dev)
{
- const struct iommu_ops *ops = dev->bus->iommu_ops;
+ const struct iommu_ops *ops = dev_iommu_ops(dev);
struct iommu_group *group;
int ret;

@@ -1588,9 +1591,6 @@ static struct iommu_group *iommu_group_get_for_dev(struct device *dev)
if (group)
return group;

- if (!ops)
- return ERR_PTR(-EINVAL);
-
group = ops->device_group(dev);
if (WARN_ON_ONCE(group == NULL))
return ERR_PTR(-EINVAL);
@@ -1759,10 +1759,10 @@ static int __iommu_group_dma_attach(struct iommu_group *group)

static int iommu_group_do_probe_finalize(struct device *dev, void *data)
{
- struct iommu_domain *domain = data;
+ const struct iommu_ops *ops = dev_iommu_ops(dev);

- if (domain->ops->probe_finalize)
- domain->ops->probe_finalize(dev);
+ if (ops->probe_finalize)
+ ops->probe_finalize(dev);

return 0;
}
@@ -2020,7 +2020,7 @@ EXPORT_SYMBOL_GPL(iommu_attach_device);

int iommu_deferred_attach(struct device *dev, struct iommu_domain *domain)
{
- const struct iommu_ops *ops = domain->ops;
+ const struct iommu_ops *ops = dev_iommu_ops(dev);

if (ops->is_attach_deferred && ops->is_attach_deferred(domain, dev))
return __iommu_attach_device(domain, dev);
@@ -2579,17 +2579,17 @@ EXPORT_SYMBOL_GPL(iommu_set_pgtable_quirks);

void iommu_get_resv_regions(struct device *dev, struct list_head *list)
{
- const struct iommu_ops *ops = dev->bus->iommu_ops;
+ const struct iommu_ops *ops = dev_iommu_ops(dev);

- if (ops && ops->get_resv_regions)
+ if (ops->get_resv_regions)
ops->get_resv_regions(dev, list);
}

void iommu_put_resv_regions(struct device *dev, struct list_head *list)
{
- const struct iommu_ops *ops = dev->bus->iommu_ops;
+ const struct iommu_ops *ops = dev_iommu_ops(dev);

- if (ops && ops->put_resv_regions)
+ if (ops->put_resv_regions)
ops->put_resv_regions(dev, list);
}

@@ -2794,9 +2794,9 @@ iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata)
{
struct iommu_group *group;
struct iommu_sva *handle = ERR_PTR(-EINVAL);
- const struct iommu_ops *ops = dev->bus->iommu_ops;
+ const struct iommu_ops *ops = dev_iommu_ops(dev);

- if (!ops || !ops->sva_bind)
+ if (!ops->sva_bind)
return ERR_PTR(-ENODEV);

group = iommu_group_get(dev);
@@ -2837,9 +2837,9 @@ void iommu_sva_unbind_device(struct iommu_sva *handle)
{
struct iommu_group *group;
struct device *dev = handle->dev;
- const struct iommu_ops *ops = dev->bus->iommu_ops;
+ const struct iommu_ops *ops = dev_iommu_ops(dev);

- if (!ops || !ops->sva_unbind)
+ if (!ops->sva_unbind)
return;

group = iommu_group_get(dev);
@@ -2856,9 +2856,9 @@ EXPORT_SYMBOL_GPL(iommu_sva_unbind_device);

u32 iommu_sva_get_pasid(struct iommu_sva *handle)
{
- const struct iommu_ops *ops = handle->dev->bus->iommu_ops;
+ const struct iommu_ops *ops = dev_iommu_ops(handle->dev);

- if (!ops || !ops->sva_get_pasid)
+ if (!ops->sva_get_pasid)
return IOMMU_PASID_INVALID;

return ops->sva_get_pasid(handle);
--
2.25.1