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Commit b27507bb authored by Juliet Kim's avatar Juliet Kim Committed by David S. Miller
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net/ibmvnic: unlock rtnl_lock in reset so linkwatch_event can run 



Commit a5681e20 ("net/ibmnvic: Fix deadlock problem in reset")
made the change to hold the RTNL lock during a reset to avoid deadlock
but linkwatch_event is fired during the reset and needs the RTNL lock.
That keeps linkwatch_event process from proceeding until the reset
is complete. The reset process cannot tolerate the linkwatch_event
processing after reset completes, so release the RTNL lock during the
process to allow a chance for linkwatch_event to run during reset.
This does not guarantee that the linkwatch_event will be processed as
soon as link state changes, but is an improvement over the current code
where linkwatch_event processing is always delayed, which prevents
transmissions on the device from being deactivated leading transmit
watchdog timer to time-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 the reset.

Fixes: a5681e20 ("net/ibmnvic: Fix deadlock problem in reset")
Signed-off-by: default avatarJuliet Kim <julietk@linux.vnet.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 5aafeb74

drivers/net/ethernet/ibm/ibmvnic.c

+156 −68
Original line number Diff line number Diff line
@@ -1723,6 +1723,86 @@ 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);

	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.
@@ -1738,6 +1818,8 @@ static int do_reset(struct ibmvnic_adapter *adapter, 
	netdev_dbg(adapter->netdev, "Re-setting driver (%d)\n",

		   rwi->reset_reason);



	rtnl_lock();



	netif_carrier_off(netdev);

	adapter->reset_reason = rwi->reset_reason;
@@ -1751,16 +1833,25 @@ 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) {

		rc = __ibmvnic_close(netdev);

		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)

			return rc;

			goto out;



		if (adapter->state != VNIC_CLOSING) {

			rc = -1;

			goto out;

		}



	if (adapter->reset_reason == VNIC_RESET_CHANGE_PARAM ||

	    adapter->wait_for_reset) {

		release_resources(adapter);

		release_sub_crqs(adapter, 1);

		release_crq_queue(adapter);

		adapter->state = VNIC_CLOSED;

	}



	if (adapter->reset_reason != VNIC_RESET_NON_FATAL) {
@@ -1769,9 +1860,7 @@ static int do_reset(struct ibmvnic_adapter *adapter, 
		 */

		adapter->state = VNIC_PROBED;



		if (adapter->wait_for_reset) {

			rc = init_crq_queue(adapter);

		} else if (adapter->reset_reason == VNIC_RESET_MOBILITY) {

		if (adapter->reset_reason == VNIC_RESET_MOBILITY) {

			rc = ibmvnic_reenable_crq_queue(adapter);

			release_sub_crqs(adapter, 1);

		} else {
@@ -1783,31 +1872,30 @@ static int do_reset(struct ibmvnic_adapter *adapter, 
		if (rc) {

			netdev_err(adapter->netdev,

				   "Couldn't initialize crq. rc=%d\n", rc);

			return rc;

			goto out;

		}



		rc = ibmvnic_reset_init(adapter);

		if (rc)

			return IBMVNIC_INIT_FAILED;

		if (rc) {

			rc = IBMVNIC_INIT_FAILED;

			goto out;

		}



		/* If the adapter was in PROBE state prior to the reset,

		 * exit here.

		 */

		if (reset_state == VNIC_PROBED)

			return 0;

		if (reset_state == VNIC_PROBED) {

			rc = 0;

			goto out;

		}



		rc = ibmvnic_login(netdev);

		if (rc) {

			adapter->state = reset_state;

			return rc;

			goto out;

		}



		if (adapter->reset_reason == VNIC_RESET_CHANGE_PARAM ||

		    adapter->wait_for_reset) {

			rc = init_resources(adapter);

			if (rc)

				return rc;

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

		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 ||
@@ -1820,32 +1908,30 @@ static int do_reset(struct ibmvnic_adapter *adapter, 


			rc = init_resources(adapter);

			if (rc)

				return rc;

				goto out;



		} else {

			rc = reset_tx_pools(adapter);

			if (rc)

				return rc;

				goto out;



			rc = reset_rx_pools(adapter);

			if (rc)

				return rc;

				goto out;

		}

		ibmvnic_disable_irqs(adapter);

	}

	adapter->state = VNIC_CLOSED;



	if (reset_state == VNIC_CLOSED)

		return 0;

	if (reset_state == VNIC_CLOSED) {

		rc = 0;

		goto out;

	}



	rc = __ibmvnic_open(netdev);

	if (rc) {

		if (list_empty(&adapter->rwi_list))

			adapter->state = VNIC_CLOSED;

		else

			adapter->state = reset_state;



		return 0;

		rc = IBMVNIC_OPEN_FAILED;

		goto out;

	}



	/* refresh device's multicast list */
@@ -1855,11 +1941,15 @@ static int do_reset(struct ibmvnic_adapter *adapter, 
	for (i = 0; i < adapter->req_rx_queues; i++)

		napi_schedule(&adapter->napi[i]);



	if (adapter->reset_reason != VNIC_RESET_FAILOVER &&

	    adapter->reset_reason != VNIC_RESET_CHANGE_PARAM)

	if (adapter->reset_reason != VNIC_RESET_FAILOVER)

		call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, netdev);



	return 0;

	rc = 0;



out:

	rtnl_unlock();



	return rc;

}



static int do_hard_reset(struct ibmvnic_adapter *adapter,
@@ -1919,14 +2009,8 @@ static int do_hard_reset(struct ibmvnic_adapter *adapter, 
		return 0;



	rc = __ibmvnic_open(netdev);

	if (rc) {

		if (list_empty(&adapter->rwi_list))

			adapter->state = VNIC_CLOSED;

		else

			adapter->state = reset_state;



		return 0;

	}

	if (rc)

		return IBMVNIC_OPEN_FAILED;



	return 0;

}
@@ -1965,20 +2049,11 @@ static void __ibmvnic_reset(struct work_struct *work) 
{

	struct ibmvnic_rwi *rwi;

	struct ibmvnic_adapter *adapter;

	bool we_lock_rtnl = false;

	u32 reset_state;

	int rc = 0;



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



	/* 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);
@@ -1990,14 +2065,32 @@ static void __ibmvnic_reset(struct work_struct *work) 
			break;

		}



		if (adapter->force_reset_recovery) {

		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) {

			/* Transport event occurred during previous reset */

			if (adapter->wait_for_reset) {

				/* Previous was CHANGE_PARAM; caller locked */

				adapter->force_reset_recovery = false;

				rc = do_hard_reset(adapter, rwi, reset_state);

			} else {

				rtnl_lock();

				adapter->force_reset_recovery = false;

				rc = do_hard_reset(adapter, rwi, reset_state);

				rtnl_unlock();

			}

		} else {

			rc = do_reset(adapter, rwi, reset_state);

		}

		kfree(rwi);

		if (rc && rc != IBMVNIC_INIT_FAILED &&

		if (rc == IBMVNIC_OPEN_FAILED) {

			if (list_empty(&adapter->rwi_list))

				adapter->state = VNIC_CLOSED;

			else

				adapter->state = reset_state;

			rc = 0;

		} else if (rc && rc != IBMVNIC_INIT_FAILED &&

		    !adapter->force_reset_recovery)

			break;
@@ -2005,7 +2098,6 @@ static void __ibmvnic_reset(struct work_struct *work) 
	}



	if (adapter->wait_for_reset) {

		adapter->wait_for_reset = false;

		adapter->reset_done_rc = rc;

		complete(&adapter->reset_done);

	}
@@ -2016,8 +2108,6 @@ static void __ibmvnic_reset(struct work_struct *work) 
	}



	adapter->resetting = false;

	if (we_lock_rtnl)

		rtnl_unlock();

}



static int ibmvnic_reset(struct ibmvnic_adapter *adapter,
@@ -2078,8 +2168,6 @@ static int ibmvnic_reset(struct ibmvnic_adapter *adapter, 


	return 0;

err:

	if (adapter->wait_for_reset)

		adapter->wait_for_reset = false;

	return -ret;

}

drivers/net/ethernet/ibm/ibmvnic.h

+1 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
#define IBMVNIC_INVALID_MAP	-1

#define IBMVNIC_STATS_TIMEOUT	1

#define IBMVNIC_INIT_FAILED	2

#define IBMVNIC_OPEN_FAILED	3



/* basic structures plus 100 2k buffers */

#define IBMVNIC_IO_ENTITLEMENT_DEFAULT	610305