From 4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36 Mon Sep 17 00:00:00 2001 From: Wei Wang Date: Sat, 17 Jun 2017 10:42:28 -0700 Subject: [PATCH] net: introduce a new function dst_dev_put() This function should be called when removing routes from fib tree after the dst gc is no longer in use. We first mark DST_OBSOLETE_DEAD on this dst to make sure next dst_ops->check() fails and returns NULL. Secondly, as we no longer keep the gc_list, we need to properly release dst->dev right at the moment when the dst is removed from the fib/fib6 tree. It does the following: 1. change dst->input and output pointers to dst_discard/dst_dscard_out to discard all packets 2. replace dst->dev with loopback interface Signed-off-by: Wei Wang Acked-by: Martin KaFai Lau Signed-off-by: David S. Miller --- include/net/dst.h | 1 + net/core/dst.c | 24 ++++++++++++++++++++++++ 2 files changed, 25 insertions(+) diff --git a/include/net/dst.h b/include/net/dst.h index 2735d5a..11d7798 100644 --- a/include/net/dst.h +++ b/include/net/dst.h @@ -428,6 +428,7 @@ void dst_init(struct dst_entry *dst, struct dst_ops *ops, unsigned short flags); void __dst_free(struct dst_entry *dst); struct dst_entry *dst_destroy(struct dst_entry *dst); +void dst_dev_put(struct dst_entry *dst); static inline void dst_free(struct dst_entry *dst) { diff --git a/net/core/dst.c b/net/core/dst.c index 551834c..56998f6 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -296,6 +296,30 @@ static void dst_destroy_rcu(struct rcu_head *head) __dst_free(dst); } +/* Operations to mark dst as DEAD and clean up the net device referenced + * by dst: + * 1. put the dst under loopback interface and discard all tx/rx packets + * on this route. + * 2. release the net_device + * This function should be called when removing routes from the fib tree + * in preparation for a NETDEV_DOWN/NETDEV_UNREGISTER event and also to + * make the next dst_ops->check() fail. + */ +void dst_dev_put(struct dst_entry *dst) +{ + struct net_device *dev = dst->dev; + + dst->obsolete = DST_OBSOLETE_DEAD; + if (dst->ops->ifdown) + dst->ops->ifdown(dst, dev, true); + dst->input = dst_discard; + dst->output = dst_discard_out; + dst->dev = dev_net(dst->dev)->loopback_dev; + dev_hold(dst->dev); + dev_put(dev); +} +EXPORT_SYMBOL(dst_dev_put); + void dst_release(struct dst_entry *dst) { if (dst) { -- 2.7.4