From 7d88d8b5570b6adba39289487138cff38f84336d Mon Sep 17 00:00:00 2001 From: David Ahern Date: Wed, 22 May 2019 20:27:56 -0700 Subject: [PATCH] ipv6: Refactor fib6_drop_pcpu_from Move the existing pcpu walk in fib6_drop_pcpu_from to a new helper, __fib6_drop_pcpu_from, that can be invoked per fib6_nh with a reference to the from entries that need to be evicted. If the passed in 'from' is non-NULL then only entries associated with that fib6_info are removed (e.g., case where fib entry is deleted); if the 'from' is NULL are entries are flushed (e.g., fib6_nh is deleted). For fib6_info entries with builtin fib6_nh (ie., current code) there is no change in behavior. Signed-off-by: David Ahern Signed-off-by: David S. Miller --- net/ipv6/ip6_fib.c | 35 +++++++++++++++++++++++++---------- 1 file changed, 25 insertions(+), 10 deletions(-) diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index 274f1243866f..178a9c2d2d34 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -874,21 +874,15 @@ static struct fib6_node *fib6_add_1(struct net *net, return ln; } -static void fib6_drop_pcpu_from(struct fib6_info *f6i, - const struct fib6_table *table) +static void __fib6_drop_pcpu_from(struct fib6_nh *fib6_nh, + const struct fib6_info *match, + const struct fib6_table *table) { - struct fib6_nh *fib6_nh = &f6i->fib6_nh; int cpu; if (!fib6_nh->rt6i_pcpu) return; - /* Make sure rt6_make_pcpu_route() wont add other percpu routes - * while we are cleaning them here. - */ - f6i->fib6_destroying = 1; - mb(); /* paired with the cmpxchg() in rt6_make_pcpu_route() */ - /* release the reference to this fib entry from * all of its cached pcpu routes */ @@ -898,7 +892,13 @@ static void fib6_drop_pcpu_from(struct fib6_info *f6i, ppcpu_rt = per_cpu_ptr(fib6_nh->rt6i_pcpu, cpu); pcpu_rt = *ppcpu_rt; - if (pcpu_rt) { + + /* only dropping the 'from' reference if the cached route + * is using 'match'. The cached pcpu_rt->from only changes + * from a fib6_info to NULL (ip6_dst_destroy); it can never + * change from one fib6_info reference to another + */ + if (pcpu_rt && rcu_access_pointer(pcpu_rt->from) == match) { struct fib6_info *from; from = xchg((__force struct fib6_info **)&pcpu_rt->from, NULL); @@ -907,6 +907,21 @@ static void fib6_drop_pcpu_from(struct fib6_info *f6i, } } +static void fib6_drop_pcpu_from(struct fib6_info *f6i, + const struct fib6_table *table) +{ + struct fib6_nh *fib6_nh; + + /* Make sure rt6_make_pcpu_route() wont add other percpu routes + * while we are cleaning them here. + */ + f6i->fib6_destroying = 1; + mb(); /* paired with the cmpxchg() in rt6_make_pcpu_route() */ + + fib6_nh = &f6i->fib6_nh; + __fib6_drop_pcpu_from(fib6_nh, f6i, table); +} + static void fib6_purge_rt(struct fib6_info *rt, struct fib6_node *fn, struct net *net) {