From f607a158004d75c9005423ce1ba70dc6ec3dd9c2 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 12 May 2011 17:46:56 -0400 Subject: [PATCH] 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: Eric Dumazet Signed-off-by: David S. Miller --- include/net/garp.h | 1 + net/802/garp.c | 14 ++++++++++++-- 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/include/net/garp.h b/include/net/garp.h index 8cabbf087169ac..834d8add9e5fd5 100644 --- a/include/net/garp.h +++ b/include/net/garp.h @@ -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 { diff --git a/net/802/garp.c b/net/802/garp.c index 5dbe8967bbd56b..f8300a8b5fbcf2 100644 --- a/net/802/garp.c +++ b/net/802/garp.c @@ -603,6 +603,11 @@ int garp_init_applicant(struct net_device *dev, struct garp_application *appl) } 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);