From 48752e1b1802231ef2a076f34d861918b7d571c3 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 9 May 2011 04:40:44 +0000 Subject: [PATCH] vlan: remove one synchronize_net() call MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit At VLAN dismantle phase, unregister_vlan_dev() makes one synchronize_net() call after vlan_group_set_device(grp, vlan_id, NULL). This call can be safely removed because we are calling unregister_netdevice_queue() to queue device for deletion, and this process needs at least one rcu grace period to complete. Signed-off-by: Eric Dumazet Cc: Ben Greear Cc: Patrick McHardy Cc: Paul E. McKenney Cc: Jesse Gross Cc: Michał Mirosław Acked-by: Jesse Gross Signed-off-by: David S. Miller --- include/linux/if_vlan.h | 1 - net/8021q/vlan.c | 10 ++++------ 2 files changed, 4 insertions(+), 7 deletions(-) diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h index 546d9d35fbd4..290bd8ac94cf 100644 --- a/include/linux/if_vlan.h +++ b/include/linux/if_vlan.h @@ -86,7 +86,6 @@ struct vlan_group { * the vlan is attached to. */ unsigned int nr_vlans; - int killall; struct hlist_node hlist; /* linked list */ struct net_device **vlan_devices_arrays[VLAN_GROUP_ARRAY_SPLIT_PARTS]; struct rcu_head rcu; diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c index 969e7004cf86..718d635d3379 100644 --- a/net/8021q/vlan.c +++ b/net/8021q/vlan.c @@ -120,9 +120,10 @@ void unregister_vlan_dev(struct net_device *dev, struct list_head *head) grp->nr_vlans--; vlan_group_set_device(grp, vlan_id, NULL); - if (!grp->killall) - synchronize_net(); - + /* Because unregister_netdevice_queue() makes sure at least one rcu + * grace period is respected before device freeing, + * we dont need to call synchronize_net() here. + */ unregister_netdevice_queue(dev, head); /* If the group is now empty, kill off the group. */ @@ -478,9 +479,6 @@ static int vlan_device_event(struct notifier_block *unused, unsigned long event, if (dev->reg_state != NETREG_UNREGISTERING) break; - /* Delete all VLANs for this dev. */ - grp->killall = 1; - for (i = 0; i < VLAN_N_VID; i++) { vlandev = vlan_group_get_device(grp, i); if (!vlandev) -- 2.39.2