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Commit f607a158 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

garp: remove last synchronize_rcu() call 



When removing last vlan from a device, garp_uninit_applicant() calls
synchronize_rcu() to make sure no user can still manipulate struct
garp_applicant before we free it.

Use call_rcu() instead, as a step to further net_device dismantle
optimizations.

Add the temporary garp_cleanup_module() function to make sure no pending
call_rcu() are left at module unload time [ this will be removed when
kfree_rcu() is available ]

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e154b639

include/net/garp.h

+1 −0
Original line number Diff line number Diff line
@@ -104,6 +104,7 @@ struct garp_applicant { 
	struct sk_buff_head	queue;

	struct sk_buff		*pdu;

	struct rb_root		gid;

	struct rcu_head		rcu;

};



struct garp_port {

net/802/garp.c

+12 −2
Original line number Diff line number Diff line
@@ -603,6 +603,11 @@ err1: 
}

EXPORT_SYMBOL_GPL(garp_init_applicant);



static void garp_app_kfree_rcu(struct rcu_head *head)

{

	kfree(container_of(head, struct garp_applicant, rcu));

}



void garp_uninit_applicant(struct net_device *dev, struct garp_application *appl)

{

	struct garp_port *port = rtnl_dereference(dev->garp_port);
@@ -611,7 +616,6 @@ void garp_uninit_applicant(struct net_device *dev, struct garp_application *appl 
	ASSERT_RTNL();



	rcu_assign_pointer(port->applicants[appl->type], NULL);

	synchronize_rcu();



	/* Delete timer and generate a final TRANSMIT_PDU event to flush out

	 * all pending messages before the applicant is gone. */
@@ -621,7 +625,7 @@ void garp_uninit_applicant(struct net_device *dev, struct garp_application *appl 
	garp_queue_xmit(app);



	dev_mc_del(dev, appl->proto.group_address);

	kfree(app);

	call_rcu(&app->rcu, garp_app_kfree_rcu);

	garp_release_port(dev);

}

EXPORT_SYMBOL_GPL(garp_uninit_applicant);
@@ -639,3 +643,9 @@ void garp_unregister_application(struct garp_application *appl) 
	stp_proto_unregister(&appl->proto);

}

EXPORT_SYMBOL_GPL(garp_unregister_application);



static void __exit garp_cleanup_module(void)

{

	rcu_barrier(); /* Wait for completion of call_rcu()'s */

}

module_exit(garp_cleanup_module);