diff options
Diffstat (limited to 'drivers/infiniband/ulp/ipoib/ipoib_vlan.c')
-rw-r--r-- | drivers/infiniband/ulp/ipoib/ipoib_vlan.c | 98 |
1 files changed, 64 insertions, 34 deletions
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c index 7776334cf8c5..891c5b40018a 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c @@ -125,23 +125,16 @@ int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey) snprintf(intf_name, sizeof(intf_name), "%s.%04x", ppriv->dev->name, pkey); - if (!mutex_trylock(&ppriv->sysfs_mutex)) + if (!rtnl_trylock()) return restart_syscall(); - if (!rtnl_trylock()) { - mutex_unlock(&ppriv->sysfs_mutex); - return restart_syscall(); - } - if (pdev->reg_state != NETREG_REGISTERED) { rtnl_unlock(); - mutex_unlock(&ppriv->sysfs_mutex); return -EPERM; } if (!down_write_trylock(&ppriv->vlan_rwsem)) { rtnl_unlock(); - mutex_unlock(&ppriv->sysfs_mutex); return restart_syscall(); } @@ -178,58 +171,95 @@ int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey) out: up_write(&ppriv->vlan_rwsem); rtnl_unlock(); - mutex_unlock(&ppriv->sysfs_mutex); return result; } +struct ipoib_vlan_delete_work { + struct work_struct work; + struct net_device *dev; +}; + +/* + * sysfs callbacks of a netdevice cannot obtain the rtnl lock as + * unregister_netdev ultimately deletes the sysfs files while holding the rtnl + * lock. This deadlocks the system. + * + * A callback can use rtnl_trylock to avoid the deadlock but it cannot call + * unregister_netdev as that internally takes and releases the rtnl_lock. So + * instead we find the netdev to unregister and then do the actual unregister + * from the global work queue where we can obtain the rtnl_lock safely. + */ +static void ipoib_vlan_delete_task(struct work_struct *work) +{ + struct ipoib_vlan_delete_work *pwork = + container_of(work, struct ipoib_vlan_delete_work, work); + struct net_device *dev = pwork->dev; + + rtnl_lock(); + + /* Unregistering tasks can race with another task or parent removal */ + if (dev->reg_state == NETREG_REGISTERED) { + struct ipoib_dev_priv *priv = ipoib_priv(dev); + struct ipoib_dev_priv *ppriv = ipoib_priv(priv->parent); + + down_write(&ppriv->vlan_rwsem); + list_del(&priv->list); + up_write(&ppriv->vlan_rwsem); + + ipoib_dbg(ppriv, "delete child vlan %s\n", dev->name); + unregister_netdevice(dev); + } + + rtnl_unlock(); + + kfree(pwork); +} + int ipoib_vlan_delete(struct net_device *pdev, unsigned short pkey) { struct ipoib_dev_priv *ppriv, *priv, *tpriv; - struct net_device *dev = NULL; + int rc; if (!capable(CAP_NET_ADMIN)) return -EPERM; - ppriv = ipoib_priv(pdev); - - if (!mutex_trylock(&ppriv->sysfs_mutex)) + if (!rtnl_trylock()) return restart_syscall(); - if (!rtnl_trylock()) { - mutex_unlock(&ppriv->sysfs_mutex); - return restart_syscall(); - } - if (pdev->reg_state != NETREG_REGISTERED) { rtnl_unlock(); - mutex_unlock(&ppriv->sysfs_mutex); return -EPERM; } - if (!down_write_trylock(&ppriv->vlan_rwsem)) { - rtnl_unlock(); - mutex_unlock(&ppriv->sysfs_mutex); - return restart_syscall(); - } + ppriv = ipoib_priv(pdev); + rc = -ENODEV; list_for_each_entry_safe(priv, tpriv, &ppriv->child_intfs, list) { if (priv->pkey == pkey && priv->child_type == IPOIB_LEGACY_CHILD) { - list_del(&priv->list); - dev = priv->dev; + struct ipoib_vlan_delete_work *work; + + work = kmalloc(sizeof(*work), GFP_KERNEL); + if (!work) { + rc = -ENOMEM; + goto out; + } + + down_write(&ppriv->vlan_rwsem); + list_del_init(&priv->list); + up_write(&ppriv->vlan_rwsem); + work->dev = priv->dev; + INIT_WORK(&work->work, ipoib_vlan_delete_task); + queue_work(ipoib_workqueue, &work->work); + + rc = 0; break; } } - up_write(&ppriv->vlan_rwsem); - - if (dev) { - ipoib_dbg(ppriv, "delete child vlan %s\n", dev->name); - unregister_netdevice(dev); - } +out: rtnl_unlock(); - mutex_unlock(&ppriv->sysfs_mutex); - return (dev) ? 0 : -ENODEV; + return rc; } |