From mboxrd@z Thu Jan 1 00:00:00 1970 From: Juliet Kim Subject: [PATCH] net/ibmnvic: Fix deadlock problem in reset Date: Thu, 15 Nov 2018 15:44:44 -0600 Message-ID: <25faa351-51d3-3aeb-a1c9-e8d3259604dd@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Thomas Falcon , Michael Bringmann , "David S. Miller" , Tyrel Datwyler To: linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Subject: [PATCH] net/ibmnvic: Fix deadlock problem in reset From: Juliet Kim 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 ---  drivers/net/ethernet/ibm/ibmvnic.c |   59 +++++++++++++-----------------------  drivers/net/ethernet/ibm/ibmvnic.h |    2 +  2 files changed, 22 insertions(+), 39 deletions(-) diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c index 7893bef..4a5de59 100644 --- 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 18103b8..99c4f8d 100644 --- 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;