From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: [net 1/3] net: allow netdev_all_upper_get_next_dev_rcu with rtnl lock held Date: Tue, 19 Nov 2013 07:40:52 -0800 Message-ID: <1384875654-7795-2-git-send-email-jeffrey.t.kirsher@intel.com> References: <1384875654-7795-1-git-send-email-jeffrey.t.kirsher@intel.com> Cc: John Fastabend , netdev@vger.kernel.org, gospo@redhat.com, sassmann@redhat.com, Veaceslav Falico , Jeff Kirsher To: davem@davemloft.net Return-path: Received: from mga02.intel.com ([134.134.136.20]:11437 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752730Ab3KSPk6 (ORCPT ); Tue, 19 Nov 2013 10:40:58 -0500 In-Reply-To: <1384875654-7795-1-git-send-email-jeffrey.t.kirsher@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: From: John Fastabend It is useful to be able to walk all upper devices when bringing a device online where the RTNL lock is held. In this case it is safe to walk the all_adj_list because the RTNL lock is used to protect the write side as well. Here we rearrange the netdev_all_upper_get_next_dev_rcu into three routines: netdev_all_upper_get_next_dev_rcu() netdev_all_upper_get_next_dev_rtnl() netdev_all_upper_get_next_dev() One for RCU callers, one for RTNL callers and a final routine to implement the work. Both the _rcu and _rtnl variants are exposed. Where the net/ethernet/intel/ixgbe driver is a consumer of the _rtnl variant. netdev_all_upper_get_next_dev() is static. CC: Veaceslav Falico Signed-off-by: John Fastabend Tested-by: Phil Schmitt Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 6 ++-- include/linux/netdevice.h | 9 ++++++ net/core/dev.c | 43 ++++++++++++++++++++------- 3 files changed, 44 insertions(+), 14 deletions(-) diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c index bd8f523..9eeb6f0 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -4336,7 +4336,7 @@ static void ixgbe_configure_dfwd(struct ixgbe_adapter *adapter) struct list_head *iter; int err; - netdev_for_each_all_upper_dev_rcu(adapter->netdev, upper, iter) { + netdev_for_each_all_upper_dev_rtnl(adapter->netdev, upper, iter) { if (netif_is_macvlan(upper)) { struct macvlan_dev *dfwd = netdev_priv(upper); struct ixgbe_fwd_adapter *vadapter = dfwd->fwd_priv; @@ -4601,7 +4601,7 @@ static void ixgbe_up_complete(struct ixgbe_adapter *adapter) netif_tx_start_all_queues(adapter->netdev); /* enable any upper devices */ - netdev_for_each_all_upper_dev_rcu(adapter->netdev, upper, iter) { + netdev_for_each_all_upper_dev_rtnl(adapter->netdev, upper, iter) { if (netif_is_macvlan(upper)) { struct macvlan_dev *vlan = netdev_priv(upper); @@ -4803,7 +4803,7 @@ void ixgbe_down(struct ixgbe_adapter *adapter) netif_tx_disable(netdev); /* disable any upper devices */ - netdev_for_each_all_upper_dev_rcu(adapter->netdev, upper, iter) { + netdev_for_each_all_upper_dev_rtnl(adapter->netdev, upper, iter) { if (netif_is_macvlan(upper)) { struct macvlan_dev *vlan = netdev_priv(upper); diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 8b3de7c..59872b2 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2843,6 +2843,8 @@ bool netdev_has_upper_dev(struct net_device *dev, struct net_device *upper_dev); bool netdev_has_any_upper_dev(struct net_device *dev); struct net_device *netdev_all_upper_get_next_dev_rcu(struct net_device *dev, struct list_head **iter); +struct net_device *netdev_all_upper_get_next_dev_rtnl(struct net_device *dev, + struct list_head **iter); /* iterate through upper list, must be called under RCU read lock */ #define netdev_for_each_all_upper_dev_rcu(dev, updev, iter) \ @@ -2851,6 +2853,13 @@ struct net_device *netdev_all_upper_get_next_dev_rcu(struct net_device *dev, updev; \ updev = netdev_all_upper_get_next_dev_rcu(dev, &(iter))) +/* iterate through upper list, must be called under RTNL */ +#define netdev_for_each_all_upper_dev_rtnl(dev, updev, iter) \ + for (iter = &(dev)->all_adj_list.upper, \ + updev = netdev_all_upper_get_next_dev_rtnl(dev, &(iter)); \ + updev; \ + updev = netdev_all_upper_get_next_dev_rtnl(dev, &(iter))) + void *netdev_lower_get_next_private(struct net_device *dev, struct list_head **iter); void *netdev_lower_get_next_private_rcu(struct net_device *dev, diff --git a/net/core/dev.c b/net/core/dev.c index 7e00a73..79c4c1e 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4487,6 +4487,21 @@ void *netdev_adjacent_get_private(struct list_head *adj_list) } EXPORT_SYMBOL(netdev_adjacent_get_private); +static struct net_device *netdev_all_upper_get_next_dev(struct net_device *dev, + struct list_head **iter) +{ + struct netdev_adjacent *upper; + + upper = list_entry_rcu((*iter)->next, struct netdev_adjacent, list); + + if (&upper->list == &dev->all_adj_list.upper) + return NULL; + + *iter = &upper->list; + + return upper->dev; +} + /** * netdev_all_upper_get_next_dev_rcu - Get the next dev from upper list * @dev: device @@ -4498,22 +4513,28 @@ EXPORT_SYMBOL(netdev_adjacent_get_private); struct net_device *netdev_all_upper_get_next_dev_rcu(struct net_device *dev, struct list_head **iter) { - struct netdev_adjacent *upper; - WARN_ON_ONCE(!rcu_read_lock_held()); - - upper = list_entry_rcu((*iter)->next, struct netdev_adjacent, list); - - if (&upper->list == &dev->all_adj_list.upper) - return NULL; - - *iter = &upper->list; - - return upper->dev; + return netdev_all_upper_get_next_dev(dev, iter); } EXPORT_SYMBOL(netdev_all_upper_get_next_dev_rcu); /** + * netdev_all_upper_get_next_dev_rtnl - Get the next dev from upper list + * @dev: device + * @iter: list_head ** of the current position + * + * Gets the next device from the dev's upper list, starting from iter + * position. The caller must hold RTNL. + */ +struct net_device *netdev_all_upper_get_next_dev_rtnl(struct net_device *dev, + struct list_head **iter) +{ + WARN_ON_ONCE(!lockdep_rtnl_is_held()); + return netdev_all_upper_get_next_dev(dev, iter); +} +EXPORT_SYMBOL(netdev_all_upper_get_next_dev_rtnl); + +/** * netdev_lower_get_next_private - Get the next ->private from the * lower neighbour list * @dev: device -- 1.8.3.1