iommu: Merge iopf_device_param into iommu_fault_param

The struct dev_iommu contains two pointers, fault_param and iopf_param.
The fault_param pointer points to a data structure that is used to store
pending faults that are awaiting responses. The iopf_param pointer points
to a data structure that is used to store partial faults that are part of
a Page Request Group.

The fault_param and iopf_param pointers are essentially duplicate. This
causes memory waste. Merge the iopf_device_param pointer into the
iommu_fault_param pointer to consolidate the code and save memory. The
consolidated pointer would be allocated on demand when the device driver
enables the iopf on device, and would be freed after iopf is disabled.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Tested-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Longfang Liu <liulongfang@huawei.com>
Link: https://lore.kernel.org/r/20240212012227.119381-6-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

1 files changed, 6 insertions, 28 deletions

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 6a4d9bc0641d..9575cb75732a 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1355,27 +1355,18 @@ int iommu_register_device_fault_handler(struct device *dev,
 	struct dev_iommu *param = dev->iommu;
 	int ret = 0;
 
-	if (!param)
+	if (!param || !param->fault_param)
 		return -EINVAL;
 
 	mutex_lock(&param->lock);
 	/* Only allow one fault handler registered for each device */
-	if (param->fault_param) {
+	if (param->fault_param->handler) {
 		ret = -EBUSY;
 		goto done_unlock;
 	}
 
-	get_device(dev);
-	param->fault_param = kzalloc(sizeof(*param->fault_param), GFP_KERNEL);
-	if (!param->fault_param) {
-		put_device(dev);
-		ret = -ENOMEM;
-		goto done_unlock;
-	}
 	param->fault_param->handler = handler;
 	param->fault_param->data = data;
-	mutex_init(&param->fault_param->lock);
-	INIT_LIST_HEAD(&param->fault_param->faults);
 
 done_unlock:
 	mutex_unlock(&param->lock);
@@ -1396,29 +1387,16 @@ EXPORT_SYMBOL_GPL(iommu_register_device_fault_handler);
 int iommu_unregister_device_fault_handler(struct device *dev)
 {
 	struct dev_iommu *param = dev->iommu;
-	int ret = 0;
 
-	if (!param)
+	if (!param || !param->fault_param)
 		return -EINVAL;
 
 	mutex_lock(&param->lock);
-
-	if (!param->fault_param)
-		goto unlock;
-
-	/* we cannot unregister handler if there are pending faults */
-	if (!list_empty(&param->fault_param->faults)) {
-		ret = -EBUSY;
-		goto unlock;
-	}
-
-	kfree(param->fault_param);
-	param->fault_param = NULL;
-	put_device(dev);
-unlock:
+	param->fault_param->handler = NULL;
+	param->fault_param->data = NULL;
 	mutex_unlock(&param->lock);
 
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(iommu_unregister_device_fault_handler);