[PATCH net-next-2.6] garp: remove last synchronize_rcu() call
From: Eric Dumazet <hidden>
Date: 2011-05-12 13:29:32
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Le lundi 09 mai 2011 à 20:25 +0200, Patrick McHardy a écrit :
Am 09.05.2011 15:35, schrieb Eric Dumazet:quoted
Speedup vlan dismantling in CONFIG_VLAN_8021Q_GVRP=y cases, by using a call_rcu() to free the memory instead of waiting with expensive synchronize_rcu() [ while RTNL is held ] Signed-off-by: Eric Dumazet <redacted> Cc: Ben Greear <redacted> Cc: Patrick McHardy <redacted> Cc: Paul E. McKenney <redacted> --- Note: I'll take care of using kfree_rcu() when available in net-next-2.6Looks good to me.
Here is a followup on this patch, thanks ! [PATCH net-next-2.6] 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 <redacted> Cc: Patrick McHardy <redacted> Cc: Paul E. McKenney <redacted> Cc: Ben Greear <redacted> --- 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 8cabbf08..834d8ad 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 5dbe896..f8300a8 100644
--- a/net/802/garp.c
+++ b/net/802/garp.c@@ -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);