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: Juliet Kim <julietk@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index c9d5d0a7fbf172b14d70b33e62cb3344622b2ce7..27a6df30eafd28e6f2af2b647769e9f0857546ea 100644 (file)
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -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);
-       }
+
+       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);

diff --git a/drivers/net/ethernet/ibm/ibmvnic.h b/drivers/net/ethernet/ibm/ibmvnic.h
index 18103b811d4db398df7ce6a6e27c6bda2077c4c2..99c4f8d331ce7c489c4b3badb1d5fbbe57ff8dea 100644 (file)
--- a/drivers/net/ethernet/ibm/ibmvnic.h
+++ b/drivers/net/ethernet/ibm/ibmvnic.h
@@ -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;