Revert "iommu: handle page response timeout"

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5EOOG
CVE: NA

--------------------------------

This reverts commit da76349c.
However, the iommu_fault_param and iommu_fault_event changes
are reserved to avoid KABI change.
Signed-off-by: NGuo Mengqi <guomengqi3@huawei.com>
Reviewed-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/iommu/iommu.c

@@ -1084,39 +1084,6 @@ int iommu_group_unregister_notifier(struct iommu_group *group,
 }
 EXPORT_SYMBOL_GPL(iommu_group_unregister_notifier);
 
-static void iommu_dev_fault_timer_fn(struct timer_list *t)
-{
-	struct iommu_fault_param *fparam = from_timer(fparam, t, timer);
-	struct iommu_fault_event *evt;
-	struct iommu_fault_page_request *prm;
-
-	u64 now;
-
-	now = get_jiffies_64();
-
-	/* The goal is to ensure driver or guest page fault handler(via vfio)
-	 * send page response on time. Otherwise, limited queue resources
-	 * may be occupied by some irresponsive guests or drivers.
-	 * When per device pending fault list is not empty, we periodically checks
-	 * if any anticipated page response time has expired.
-	 *
-	 * TODO:
-	 * We could do the following if response time expires:
-	 * 1. send page response code FAILURE to all pending PRQ
-	 * 2. inform device driver or vfio
-	 * 3. drain in-flight page requests and responses for this device
-	 * 4. clear pending fault list such that driver can unregister fault
-	 *    handler(otherwise blocked when pending faults are present).
-	 */
-	list_for_each_entry(evt, &fparam->faults, list) {
-		prm = &evt->fault.prm;
-		if (time_after64(now, evt->expire))
-			pr_err("Page response time expired!, pasid %d gid %d exp %llu now %llu\n",
-				prm->pasid, prm->grpid, evt->expire, now);
-	}
-	mod_timer(t, now + prq_timeout);
-}
-
 /**
  * iommu_register_device_fault_handler() - Register a device fault handler
  * @dev: the device
@@ -1164,9 +1131,6 @@ int iommu_register_device_fault_handler(struct device *dev,
 	mutex_init(&param->fault_param->lock);
 	INIT_LIST_HEAD(&param->fault_param->faults);
 
-	if (prq_timeout)
-		timer_setup(&param->fault_param->timer, iommu_dev_fault_timer_fn,
-			TIMER_DEFERRABLE);
 done_unlock:
 	mutex_unlock(&param->lock);
 
@@ -1306,9 +1270,7 @@ int iommu_report_device_fault(struct device *dev, struct iommu_fault_event *evt)
 	struct dev_iommu *param = dev->iommu;
 	struct iommu_fault_event *evt_pending = NULL;
 	struct iommu_fault_param *fparam;
-	struct timer_list *tmr;
 	int ret = 0;
-	u64 exp;
 
 	if (!param || !evt || WARN_ON_ONCE(!iommu_fault_valid(&evt->fault)))
 		return -EINVAL;
@@ -1329,17 +1291,7 @@ int iommu_report_device_fault(struct device *dev, struct iommu_fault_event *evt)
 			ret = -ENOMEM;
 			goto done_unlock;
 		}
-		/* Keep track of response expiration time */
-		exp = get_jiffies_64() + prq_timeout;
-		evt_pending->expire = exp;
 		mutex_lock(&fparam->lock);
-		if (list_empty(&fparam->faults)) {
-			/* First pending event, start timer */
-			tmr = &fparam->timer;
-			WARN_ON(timer_pending(tmr));
-			mod_timer(tmr, exp);
-		}
-
 		list_add_tail(&evt_pending->list, &fparam->faults);
 		mutex_unlock(&fparam->lock);
 	}
@@ -1417,13 +1369,6 @@ int iommu_page_response(struct device *dev,
 		break;
 	}
 
-	/* stop response timer if no more pending request */
-	if (list_empty(&param->fault_param->faults) &&
-		timer_pending(&param->fault_param->timer)) {
-		pr_debug("no pending PRQ, stop timer\n");
-		del_timer(&param->fault_param->timer);
-	}
-
 done_unlock:
 	mutex_unlock(&param->fault_param->lock);
 	return ret;

include/linux/iommu.h

@@ -393,7 +393,7 @@ struct iommu_device {
 struct iommu_fault_event {
 	struct iommu_fault fault;
 	struct list_head list;
-	u64 expire;
+	_KABI_DEPRECATE(u64, expire);
 };
 
 /**
@@ -408,7 +408,7 @@ struct iommu_fault_param {
 	iommu_dev_fault_handler_t handler;
 	void *data;
 	struct list_head faults;
-	struct timer_list timer;
+	_KABI_DEPRECATE(struct timer_list, timer);
 	struct mutex lock;
 };