ibmvnic: merge do_change_param_reset into do_reset

Commit b27507bb ("net/ibmvnic: unlock rtnl_lock in reset so
linkwatch_event can run") introduced do_change_param_reset function to
solve the rtnl lock issue. Majority of the code in do_change_param_reset
duplicates do_reset. Also, we can handle the rtnl lock issue in do_reset
itself. Hence merge do_change_param_reset back into do_reset to clean up
the code.
Signed-off-by: Lijun Pan <ljp@linux.ibm.com>
Link: https://lore.kernel.org/r/20201031094645.17255-1-ljp@linux.ibm.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/ibm/ibmvnic.c

@@ -1826,86 +1826,6 @@ static int ibmvnic_set_mac(struct net_device *netdev, void *p)
 	return rc;
 }
 
-/**
- * do_change_param_reset returns zero if we are able to keep processing reset
- * events, or non-zero if we hit a fatal error and must halt.
- */
-static int do_change_param_reset(struct ibmvnic_adapter *adapter,
-				 struct ibmvnic_rwi *rwi,
-				 u32 reset_state)
-{
-	struct net_device *netdev = adapter->netdev;
-	int i, rc;
-
-	netdev_dbg(adapter->netdev, "Change param resetting driver (%d)\n",
-		   rwi->reset_reason);
-
-	netif_carrier_off(netdev);
-	adapter->reset_reason = rwi->reset_reason;
-
-	ibmvnic_cleanup(netdev);
-
-	if (reset_state == VNIC_OPEN) {
-		rc = __ibmvnic_close(netdev);
-		if (rc)
-			return rc;
-	}
-
-	release_resources(adapter);
-	release_sub_crqs(adapter, 1);
-	release_crq_queue(adapter);
-
-	adapter->state = VNIC_PROBED;
-
-	rc = init_crq_queue(adapter);
-
-	if (rc) {
-		netdev_err(adapter->netdev,
-			   "Couldn't initialize crq. rc=%d\n", rc);
-		return rc;
-	}
-
-	rc = ibmvnic_reset_init(adapter, true);
-	if (rc)
-		return IBMVNIC_INIT_FAILED;
-
-	/* If the adapter was in PROBE state prior to the reset,
-	 * exit here.
-	 */
-	if (reset_state == VNIC_PROBED)
-		return 0;
-
-	rc = ibmvnic_login(netdev);
-	if (rc) {
-		adapter->state = reset_state;
-		return rc;
-	}
-
-	rc = init_resources(adapter);
-	if (rc)
-		return rc;
-
-	ibmvnic_disable_irqs(adapter);
-
-	adapter->state = VNIC_CLOSED;
-
-	if (reset_state == VNIC_CLOSED)
-		return 0;
-
-	rc = __ibmvnic_open(netdev);
-	if (rc)
-		return IBMVNIC_OPEN_FAILED;
-
-	/* refresh device's multicast list */
-	ibmvnic_set_multi(netdev);
-
-	/* kick napi */
-	for (i = 0; i < adapter->req_rx_queues; i++)
-		napi_schedule(&adapter->napi[i]);
-
-	return 0;
-}
-
 /**
  * do_reset returns zero if we are able to keep processing reset events, or
  * non-zero if we hit a fatal error and must halt.
@@ -1921,10 +1841,12 @@ static int do_reset(struct ibmvnic_adapter *adapter,
 	netdev_dbg(adapter->netdev, "Re-setting driver (%d)\n",
 		   rwi->reset_reason);
 
-	rtnl_lock();
+	adapter->reset_reason = rwi->reset_reason;
+	/* requestor of VNIC_RESET_CHANGE_PARAM already has the rtnl lock */
+	if (!(adapter->reset_reason == VNIC_RESET_CHANGE_PARAM))
+		rtnl_lock();
 
 	netif_carrier_off(netdev);
-	adapter->reset_reason = rwi->reset_reason;
 
 	old_num_rx_queues = adapter->req_rx_queues;
 	old_num_tx_queues = adapter->req_tx_queues;
@@ -1936,25 +1858,37 @@ static int do_reset(struct ibmvnic_adapter *adapter,
 	if (reset_state == VNIC_OPEN &&
 	    adapter->reset_reason != VNIC_RESET_MOBILITY &&
 	    adapter->reset_reason != VNIC_RESET_FAILOVER) {
-		adapter->state = VNIC_CLOSING;
+		if (adapter->reset_reason == VNIC_RESET_CHANGE_PARAM) {
+			rc = __ibmvnic_close(netdev);
+			if (rc)
+				goto out;
+		} else {
+			adapter->state = VNIC_CLOSING;
 
-		/* Release the RTNL lock before link state change and
-		 * re-acquire after the link state change to allow
-		 * linkwatch_event to grab the RTNL lock and run during
-		 * a reset.
-		 */
-		rtnl_unlock();
-		rc = set_link_state(adapter, IBMVNIC_LOGICAL_LNK_DN);
-		rtnl_lock();
-		if (rc)
-			goto out;
+			/* Release the RTNL lock before link state change and
+			 * re-acquire after the link state change to allow
+			 * linkwatch_event to grab the RTNL lock and run during
+			 * a reset.
+			 */
+			rtnl_unlock();
+			rc = set_link_state(adapter, IBMVNIC_LOGICAL_LNK_DN);
+			rtnl_lock();
+			if (rc)
+				goto out;
 
-		if (adapter->state != VNIC_CLOSING) {
-			rc = -1;
-			goto out;
+			if (adapter->state != VNIC_CLOSING) {
+				rc = -1;
+				goto out;
+			}
+
+			adapter->state = VNIC_CLOSED;
 		}
+	}
 
-		adapter->state = VNIC_CLOSED;
+	if (adapter->reset_reason == VNIC_RESET_CHANGE_PARAM) {
+		release_resources(adapter);
+		release_sub_crqs(adapter, 1);
+		release_crq_queue(adapter);
 	}
 
 	if (adapter->reset_reason != VNIC_RESET_NON_FATAL) {
@@ -1963,7 +1897,9 @@ static int do_reset(struct ibmvnic_adapter *adapter,
 		 */
 		adapter->state = VNIC_PROBED;
 
-		if (adapter->reset_reason == VNIC_RESET_MOBILITY) {
+		if (adapter->reset_reason == VNIC_RESET_CHANGE_PARAM) {
+			rc = init_crq_queue(adapter);
+		} else if (adapter->reset_reason == VNIC_RESET_MOBILITY) {
 			rc = ibmvnic_reenable_crq_queue(adapter);
 			release_sub_crqs(adapter, 1);
 		} else {
@@ -2003,7 +1939,11 @@ static int do_reset(struct ibmvnic_adapter *adapter,
 			goto out;
 		}
 
-		if (adapter->req_rx_queues != old_num_rx_queues ||
+		if (adapter->reset_reason == VNIC_RESET_CHANGE_PARAM) {
+			rc = init_resources(adapter);
+			if (rc)
+				goto out;
+		} else if (adapter->req_rx_queues != old_num_rx_queues ||
 		    adapter->req_tx_queues != old_num_tx_queues ||
 		    adapter->req_rx_add_entries_per_subcrq !=
 		    old_num_rx_slots ||
@@ -2064,7 +2004,9 @@ static int do_reset(struct ibmvnic_adapter *adapter,
 	rc = 0;
 
 out:
-	rtnl_unlock();
+	/* requestor of VNIC_RESET_CHANGE_PARAM should still hold the rtnl lock */
+	if (!(adapter->reset_reason == VNIC_RESET_CHANGE_PARAM))
+		rtnl_unlock();
 
 	return rc;
 }
@@ -2198,10 +2140,7 @@ static void __ibmvnic_reset(struct work_struct *work)
 		}
 		spin_unlock_irqrestore(&adapter->state_lock, flags);
 
-		if (rwi->reset_reason == VNIC_RESET_CHANGE_PARAM) {
-			/* CHANGE_PARAM requestor holds rtnl_lock */
-			rc = do_change_param_reset(adapter, rwi, reset_state);
-		} else if (adapter->force_reset_recovery) {
+		if (adapter->force_reset_recovery) {
 			/* Transport event occurred during previous reset */
 			if (adapter->wait_for_reset) {
 				/* Previous was CHANGE_PARAM; caller locked */