On 2023/8/3 16:16, Tian, Kevin wrote:
From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Sent: Thursday, July 27, 2023 1:49 PM
@@ -82,7 +82,7 @@ static void iopf_handler(struct work_struct *work)
if (!domain || !domain->iopf_handler)
status = IOMMU_PAGE_RESP_INVALID;
- list_for_each_entry_safe(iopf, next, &group->faults, list) {
+ list_for_each_entry(iopf, &group->faults, list) {
/*
* For the moment, errors are sticky: don't handle
subsequent
* faults in the group if there is an error.
@@ -90,14 +90,20 @@ static void iopf_handler(struct work_struct *work)
if (status == IOMMU_PAGE_RESP_SUCCESS)
status = domain->iopf_handler(&iopf->fault,
domain->fault_data);
-
- if (!(iopf->fault.prm.flags &
- IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE))
- kfree(iopf);
}
iopf_complete_group(group->dev, &group->last_fault, status);
- kfree(group);
+ iopf_free_group(group);
+}
this is perf-critical path. It's not good to traverse the list twice.
Freeing the fault group is not critical anymore, right?
+
+static int iopf_queue_work(struct iopf_group *group, work_func_t func)
+{
+ struct iopf_device_param *iopf_param = group->dev->iommu-
iopf_param;
+
+ INIT_WORK(&group->work, func);
+ queue_work(iopf_param->queue->wq, &group->work);
+
+ return 0;
}
Is there plan to introduce further error in the future? otherwise this should
be void.
queue_work() return true or false. I should check and return the value.
btw the work queue is only for sva. If there is no other caller this can be
just kept in iommu-sva.c. No need to create a helper.
The definition of struct iopf_device_param is in this file. So I added a
helper to avoid making iopf_device_param visible globally.
@@ -199,8 +204,11 @@ int iommu_queue_iopf(struct iommu_fault *fault,
struct device *dev)
list_move(&iopf->list, &group->faults);
}
- queue_work(iopf_param->queue->wq, &group->work);
- return 0;
+ ret = iopf_queue_work(group, iopf_handler);
+ if (ret)
+ iopf_free_group(group);
+
+ return ret;
Here we can document that the iopf handler (in patch10) should free the
group, allowing the optimization inside the handler.
Yeah!
Best regards,
baolu
