From 7d88d8b5570b6adba39289487138cff38f84336d Mon Sep 17 00:00:00 2001
From: David Ahern <dsahern@gmail.com>
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 <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
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 274f1243866f2..178a9c2d2d346 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -874,21 +874,15 @@ insert_above:
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)
{
--
2.30.2