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Commit 449f4544 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

macvlan: remove one synchronize_rcu() call 



When one macvlan device is dismantled, we can avoid one
synchronize_rcu() call done after deletion from hash list, since caller
will perform a synchronize_net() call after its ndo_stop() call.

Add a new netdev->dismantle field to signal this dismantle intent.

Reduces RTNL hold time.

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
CC: Patrick McHardy <kaber@trash.net>
CC: Ben Greear <greearb@candelatech.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 034cfe48

drivers/net/macvlan.c

+5 −4
Original line number Diff line number Diff line
@@ -70,16 +70,17 @@ static void macvlan_hash_add(struct macvlan_dev *vlan) 
	hlist_add_head_rcu(&vlan->hlist, &port->vlan_hash[addr[5]]);

}



static void macvlan_hash_del(struct macvlan_dev *vlan)

static void macvlan_hash_del(struct macvlan_dev *vlan, bool sync)

{

	hlist_del_rcu(&vlan->hlist);

	if (sync)

		synchronize_rcu();

}



static void macvlan_hash_change_addr(struct macvlan_dev *vlan,

					const unsigned char *addr)

{

	macvlan_hash_del(vlan);

	macvlan_hash_del(vlan, true);

	/* Now that we are unhashed it is safe to change the device

	 * address without confusing packet delivery.

	 */
@@ -345,7 +346,7 @@ static int macvlan_stop(struct net_device *dev) 
	dev_uc_del(lowerdev, dev->dev_addr);



hash_del:

	macvlan_hash_del(vlan);

	macvlan_hash_del(vlan, !dev->dismantle);

	return 0;

}

include/linux/netdevice.h

+3 −1
Original line number Diff line number Diff line
@@ -1293,7 +1293,9 @@ struct net_device { 
	       NETREG_UNREGISTERED,	/* completed unregister todo */

	       NETREG_RELEASED,		/* called free_netdev */

	       NETREG_DUMMY,		/* dummy device for NAPI poll */

	} reg_state:16;

	} reg_state:8;



	bool dismantle; /* device is going do be freed */



	enum {

		RTNL_LINK_INITIALIZED,

net/core/dev.c

+1 −1
Original line number Diff line number Diff line
@@ -5126,7 +5126,7 @@ static void rollback_registered_many(struct list_head *head) 
			list_del(&dev->unreg_list);

			continue;

		}



		dev->dismantle = true;

		BUG_ON(dev->reg_state != NETREG_REGISTERED);

	}