[PATCH iwl-net 1/3] ice: avoid RTNL deadlock when notifying the RDMA auxiliary driver

@@ -355,8 +355,10 @@ int ice_pf_dcb_cfg(struct ice_pf *pf, struct ice_dcbx_cfg *new_cfg, bool locked)
 	struct iidc_rdma_event *event;
 	int ret = ICE_DCB_NO_HW_CHG;
 	struct ice_vsi *pf_vsi;
+	bool dcb_ena;
 
 	curr_cfg = &pf->hw.port_info->qos_cfg.local_dcbx_cfg;
+	dcb_ena = test_bit(ICE_FLAG_DCB_ENA, pf->flags);
 
 	/* FW does not care if change happened */
 	if (!pf->hw.port_info->qos_cfg.is_sw_lldp)

@@ -406,7 +408,12 @@ int ice_pf_dcb_cfg(struct ice_pf *pf, struct ice_dcbx_cfg *new_cfg, bool locked)
 	}
 
 	set_bit(IIDC_RDMA_EVENT_BEFORE_TC_CHANGE, event->type);
-	ice_send_event_to_aux(pf, event);
+	if (!ice_send_event_to_aux(pf, event)) {
+		assign_bit(ICE_FLAG_DCB_ENA, pf->flags, dcb_ena);
+		kfree(event);
+		ret = -EBUSY;
+		goto free_cfg;
+	}
 	kfree(event);
 
 	/* avoid race conditions by holding the lock while disabling and

@@ -34,30 +34,42 @@ ice_get_auxiliary_drv(struct iidc_rdma_core_dev_info *cdev)
  * ice_send_event_to_aux - send event to RDMA AUX driver
  * @pf: pointer to PF struct
  * @event: event struct
+ *
+ * Return: false when the auxiliary device lock was contended.
  */
-void ice_send_event_to_aux(struct ice_pf *pf, struct iidc_rdma_event *event)
+bool ice_send_event_to_aux(struct ice_pf *pf, struct iidc_rdma_event *event)
 {
 	struct iidc_rdma_core_auxiliary_drv *iadrv;
 	struct iidc_rdma_core_dev_info *cdev;
+	bool sent = true;
 
 	if (WARN_ON_ONCE(!in_task()))
-		return;
+		return true;
 
 	cdev = pf->cdev_info;
 	if (!cdev)
-		return;
+		return true;
 
 	mutex_lock(&pf->adev_mutex);
 	if (!cdev->adev)
 		goto finish;
 
-	device_lock(&cdev->adev->dev);
+	if (!device_trylock(&cdev->adev->dev)) {
+		dev_dbg(ice_pf_to_dev(pf),
+			"auxiliary device busy, dropped RDMA event 0x%lx\n",
+			*event->type);
+		sent = false;
+		goto finish;
+	}
+
 	iadrv = ice_get_auxiliary_drv(cdev);
 	if (iadrv && iadrv->event_handler)
 		iadrv->event_handler(cdev, event);
 	device_unlock(&cdev->adev->dev);
 finish:
 	mutex_unlock(&pf->adev_mutex);
+
+	return sent;
 }
 
 /**

@@ -9,6 +9,6 @@
 
 struct ice_pf;
 
-void ice_send_event_to_aux(struct ice_pf *pf, struct iidc_rdma_event *event);
+bool ice_send_event_to_aux(struct ice_pf *pf, struct iidc_rdma_event *event);
 
 #endif /* !_ICE_IDC_INT_H_ */

@@ -2313,11 +2313,16 @@ static void ice_service_task(struct work_struct *work)
 		struct iidc_rdma_event *event;
 
 		event = kzalloc_obj(*event);
-		if (event) {
+		if (!event) {
+			set_bit(ICE_AUX_ERR_PENDING, pf->state);
+		} else {
 			set_bit(IIDC_RDMA_EVENT_CRIT_ERR, event->type);
 			/* report the entire OICR value to AUX driver */
 			swap(event->reg, pf->oicr_err_reg);
-			ice_send_event_to_aux(pf, event);
+			if (!ice_send_event_to_aux(pf, event)) {
+				pf->oicr_err_reg |= event->reg;
+				set_bit(ICE_AUX_ERR_PENDING, pf->state);
+			}
 			kfree(event);
 		}
 	}

@@ -2336,9 +2341,12 @@ static void ice_service_task(struct work_struct *work)
 		struct iidc_rdma_event *event;
 
 		event = kzalloc_obj(*event);
-		if (event) {
+		if (!event) {
+			set_bit(ICE_FLAG_MTU_CHANGED, pf->flags);
+		} else {
 			set_bit(IIDC_RDMA_EVENT_AFTER_MTU_CHANGE, event->type);
-			ice_send_event_to_aux(pf, event);
+			if (!ice_send_event_to_aux(pf, event))
+				set_bit(ICE_FLAG_MTU_CHANGED, pf->flags);
 			kfree(event);
 		}
 	}