From 1cfb71eeb12047bcdbd3e6730ffed66e810a0855 Mon Sep 17 00:00:00 2001 From: Wei Wang Date: Sat, 17 Jun 2017 10:42:33 -0700 Subject: ipv6: take dst->__refcnt for insertion into fib6 tree In IPv6 routing code, struct rt6_info is created for each static route and RTF_CACHE route and inserted into fib6 tree. In both cases, dst ref count is not taken. As explained in the previous patch, this leads to the need of the dst garbage collector. This patch holds ref count of dst before inserting the route into fib6 tree and properly releases the dst when deleting it from the fib6 tree as a preparation in order to fully get rid of dst gc later. Also, correct fib6_age() logic to check dst->__refcnt to be 1 to indicate no user is referencing the dst. And remove dst_hold() in vrf_rt6_create() as ip6_dst_alloc() already puts dst->__refcnt to 1. Signed-off-by: Wei Wang Acked-by: Martin KaFai Lau Signed-off-by: David S. Miller --- net/ipv6/ip6_fib.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'net/ipv6/ip6_fib.c') diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index deea901746c8..3b728bcb1301 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -172,6 +172,7 @@ static void rt6_free_pcpu(struct rt6_info *non_pcpu_rt) ppcpu_rt = per_cpu_ptr(non_pcpu_rt->rt6i_pcpu, cpu); pcpu_rt = *ppcpu_rt; if (pcpu_rt) { + dst_release(&pcpu_rt->dst); rt6_rcu_free(pcpu_rt); *ppcpu_rt = NULL; } @@ -185,6 +186,7 @@ static void rt6_release(struct rt6_info *rt) { if (atomic_dec_and_test(&rt->rt6i_ref)) { rt6_free_pcpu(rt); + dst_release(&rt->dst); rt6_rcu_free(rt); } } @@ -1101,6 +1103,10 @@ out: atomic_inc(&pn->leaf->rt6i_ref); } #endif + /* Always release dst as dst->__refcnt is guaranteed + * to be taken before entering this function + */ + dst_release(&rt->dst); if (!(rt->dst.flags & DST_NOCACHE)) dst_free(&rt->dst); } @@ -1113,6 +1119,10 @@ out: st_failure: if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT))) fib6_repair_tree(info->nl_net, fn); + /* Always release dst as dst->__refcnt is guaranteed + * to be taken before entering this function + */ + dst_release(&rt->dst); if (!(rt->dst.flags & DST_NOCACHE)) dst_free(&rt->dst); return err; @@ -1783,7 +1793,7 @@ static int fib6_age(struct rt6_info *rt, void *arg) } gc_args->more++; } else if (rt->rt6i_flags & RTF_CACHE) { - if (atomic_read(&rt->dst.__refcnt) == 0 && + if (atomic_read(&rt->dst.__refcnt) == 1 && time_after_eq(now, rt->dst.lastuse + gc_args->timeout)) { RT6_TRACE("aging clone %p\n", rt); return -1; -- cgit v1.2.3