[PATCH v2 07/10] iommu: Use right way to retrieve iommu_ops

Lu Baolu
2022-02-08T01:49:53Z

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>
---
include/linux/iommu.h | 14 ++++++++++++++
drivers/iommu/iommu.c | 20 +++++++++++---------
2 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 9ffa2e88f3d0..eb2684f95018 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -381,6 +381,20 @@ 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.
+ */
+ WARN_ON(!dev || !dev->iommu || !dev->iommu->iommu_dev ||
+ !dev->iommu->iommu_dev->ops);
+
+ 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 df6bd1d58c74..de593a9cc09c 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -828,8 +828,10 @@ 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;
}
@@ -1248,10 +1250,10 @@ 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)
@@ -1292,7 +1294,7 @@ 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;
@@ -1755,10 +1757,10 @@ 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;
}
@@ -2016,7 +2018,7 @@ 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);
--
2.25.1