Commit a5681e20 authored by Juliet Kim's avatar Juliet Kim Committed by David S. Miller
Browse files

net/ibmnvic: Fix deadlock problem in reset 



This patch changes to use rtnl_lock only during a reset to avoid
deadlock that could occur when a thread operating close is holding
rtnl_lock and waiting for reset_lock acquired by another thread,
which is waiting for rtnl_lock in order to set the number of tx/rx
queues during a reset.

Also, we now setting the number of tx/rx queues during a soft reset
for failover or LPM events.

Signed-off-by: default avatarJuliet Kim <julietk@linux.vnet.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent db9a0bae

drivers/net/ethernet/ibm/ibmvnic.c

+21 −38
Original line number Diff line number Diff line
@@ -1103,20 +1103,15 @@ static int ibmvnic_open(struct net_device *netdev) 
		return 0;

	}



	mutex_lock(&adapter->reset_lock);



	if (adapter->state != VNIC_CLOSED) {

		rc = ibmvnic_login(netdev);

		if (rc) {

			mutex_unlock(&adapter->reset_lock);

		if (rc)

			return rc;

		}



		rc = init_resources(adapter);

		if (rc) {

			netdev_err(netdev, "failed to initialize resources\n");

			release_resources(adapter);

			mutex_unlock(&adapter->reset_lock);

			return rc;

		}

	}
@@ -1124,8 +1119,6 @@ static int ibmvnic_open(struct net_device *netdev) 
	rc = __ibmvnic_open(netdev);

	netif_carrier_on(netdev);



	mutex_unlock(&adapter->reset_lock);



	return rc;

}
@@ -1269,10 +1262,8 @@ static int ibmvnic_close(struct net_device *netdev) 
		return 0;

	}



	mutex_lock(&adapter->reset_lock);

	rc = __ibmvnic_close(netdev);

	ibmvnic_cleanup(netdev);

	mutex_unlock(&adapter->reset_lock);



	return rc;

}
@@ -1820,20 +1811,15 @@ static int do_reset(struct ibmvnic_adapter *adapter, 
				return rc;

		} else if (adapter->req_rx_queues != old_num_rx_queues ||

			   adapter->req_tx_queues != old_num_tx_queues) {

			adapter->map_id = 1;

			release_rx_pools(adapter);

			release_tx_pools(adapter);

			rc = init_rx_pools(netdev);

			if (rc)

				return rc;

			rc = init_tx_pools(netdev);

			if (rc)

				return rc;



			release_napi(adapter);

			rc = init_napi(adapter);

			release_vpd_data(adapter);



			rc = init_resources(adapter);

			if (rc)

				return rc;



		} else {

			rc = reset_tx_pools(adapter);

			if (rc)
@@ -1917,17 +1903,8 @@ static int do_hard_reset(struct ibmvnic_adapter *adapter, 
		adapter->state = VNIC_PROBED;

		return 0;

	}

	/* netif_set_real_num_xx_queues needs to take rtnl lock here

	 * unless wait_for_reset is set, in which case the rtnl lock

	 * has already been taken before initializing the reset

	 */

	if (!adapter->wait_for_reset) {

		rtnl_lock();

		rc = init_resources(adapter);

		rtnl_unlock();

	} else {



	rc = init_resources(adapter);

	}

	if (rc)

		return rc;
@@ -1986,13 +1963,21 @@ static void __ibmvnic_reset(struct work_struct *work) 
	struct ibmvnic_rwi *rwi;

	struct ibmvnic_adapter *adapter;

	struct net_device *netdev;

	bool we_lock_rtnl = false;

	u32 reset_state;

	int rc = 0;



	adapter = container_of(work, struct ibmvnic_adapter, ibmvnic_reset);

	netdev = adapter->netdev;



	mutex_lock(&adapter->reset_lock);

	/* netif_set_real_num_xx_queues needs to take rtnl lock here

	 * unless wait_for_reset is set, in which case the rtnl lock

	 * has already been taken before initializing the reset

	 */

	if (!adapter->wait_for_reset) {

		rtnl_lock();

		we_lock_rtnl = true;

	}

	reset_state = adapter->state;



	rwi = get_next_rwi(adapter);
@@ -2020,12 +2005,11 @@ static void __ibmvnic_reset(struct work_struct *work) 
	if (rc) {

		netdev_dbg(adapter->netdev, "Reset failed\n");

		free_all_rwi(adapter);

		mutex_unlock(&adapter->reset_lock);

		return;

	}



	adapter->resetting = false;

	mutex_unlock(&adapter->reset_lock);

	if (we_lock_rtnl)

		rtnl_unlock();

}



static int ibmvnic_reset(struct ibmvnic_adapter *adapter,
@@ -4768,7 +4752,6 @@ static int ibmvnic_probe(struct vio_dev *dev, const struct vio_device_id *id) 


	INIT_WORK(&adapter->ibmvnic_reset, __ibmvnic_reset);

	INIT_LIST_HEAD(&adapter->rwi_list);

	mutex_init(&adapter->reset_lock);

	mutex_init(&adapter->rwi_lock);

	adapter->resetting = false;
@@ -4840,8 +4823,8 @@ static int ibmvnic_remove(struct vio_dev *dev) 
	struct ibmvnic_adapter *adapter = netdev_priv(netdev);



	adapter->state = VNIC_REMOVING;

	unregister_netdev(netdev);

	mutex_lock(&adapter->reset_lock);

	rtnl_lock();

	unregister_netdevice(netdev);



	release_resources(adapter);

	release_sub_crqs(adapter, 1);
@@ -4852,7 +4835,7 @@ static int ibmvnic_remove(struct vio_dev *dev) 


	adapter->state = VNIC_REMOVED;



	mutex_unlock(&adapter->reset_lock);

	rtnl_unlock();

	device_remove_file(&dev->dev, &dev_attr_failover);

	free_netdev(netdev);

	dev_set_drvdata(&dev->dev, NULL);

drivers/net/ethernet/ibm/ibmvnic.h

+1 −1
Original line number Diff line number Diff line
@@ -1075,7 +1075,7 @@ struct ibmvnic_adapter { 
	struct tasklet_struct tasklet;

	enum vnic_state state;

	enum ibmvnic_reset_reason reset_reason;

	struct mutex reset_lock, rwi_lock;

	struct mutex rwi_lock;

	struct list_head rwi_list;

	struct work_struct ibmvnic_reset;

	bool resetting;

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