1 files changed, 22 insertions, 28 deletions

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 93578b2ec35f..02c16909f618 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -445,15 +445,17 @@ struct fib6_dump_arg {
 static int fib6_rt_dump(struct fib6_info *rt, struct fib6_dump_arg *arg)
 {
 	enum fib_event_type fib_event = FIB_EVENT_ENTRY_REPLACE;
+	unsigned int nsiblings;
 	int err;
 
 	if (!rt || rt == arg->net->ipv6.fib6_null_entry)
 		return 0;
 
-	if (rt->fib6_nsiblings)
+	nsiblings = READ_ONCE(rt->fib6_nsiblings);
+	if (nsiblings)
 		err = call_fib6_multipath_entry_notifier(arg->nb, fib_event,
 							 rt,
-							 rt->fib6_nsiblings,
+							 nsiblings,
 							 arg->extack);
 	else
 		err = call_fib6_entry_notifier(arg->nb, fib_event, rt,
@@ -963,8 +965,7 @@ insert_above:
 }
 
 static void __fib6_drop_pcpu_from(struct fib6_nh *fib6_nh,
-				  const struct fib6_info *match,
-				  const struct fib6_table *table)
+				  const struct fib6_info *match)
 {
 	int cpu;
 
@@ -999,21 +1000,15 @@ static void __fib6_drop_pcpu_from(struct fib6_nh *fib6_nh,
 	rcu_read_unlock();
 }
 
-struct fib6_nh_pcpu_arg {
-	struct fib6_info	*from;
-	const struct fib6_table *table;
-};
-
 static int fib6_nh_drop_pcpu_from(struct fib6_nh *nh, void *_arg)
 {
-	struct fib6_nh_pcpu_arg *arg = _arg;
+	struct fib6_info *arg = _arg;
 
-	__fib6_drop_pcpu_from(nh, arg->from, arg->table);
+	__fib6_drop_pcpu_from(nh, arg);
 	return 0;
 }
 
-static void fib6_drop_pcpu_from(struct fib6_info *f6i,
-				const struct fib6_table *table)
+static void fib6_drop_pcpu_from(struct fib6_info *f6i)
 {
 	/* Make sure rt6_make_pcpu_route() wont add other percpu routes
 	 * while we are cleaning them here.
@@ -1022,19 +1017,14 @@ static void fib6_drop_pcpu_from(struct fib6_info *f6i,
 	mb(); /* paired with the cmpxchg() in rt6_make_pcpu_route() */
 
 	if (f6i->nh) {
-		struct fib6_nh_pcpu_arg arg = {
-			.from = f6i,
-			.table = table
-		};
-
 		rcu_read_lock();
-		nexthop_for_each_fib6_nh(f6i->nh, fib6_nh_drop_pcpu_from, &arg);
+		nexthop_for_each_fib6_nh(f6i->nh, fib6_nh_drop_pcpu_from, f6i);
 		rcu_read_unlock();
 	} else {
 		struct fib6_nh *fib6_nh;
 
 		fib6_nh = f6i->fib6_nh;
-		__fib6_drop_pcpu_from(fib6_nh, f6i, table);
+		__fib6_drop_pcpu_from(fib6_nh, f6i);
 	}
 }
 
@@ -1045,7 +1035,7 @@ static void fib6_purge_rt(struct fib6_info *rt, struct fib6_node *fn,
 
 	/* Flush all cached dst in exception table */
 	rt6_flush_exceptions(rt);
-	fib6_drop_pcpu_from(rt, table);
+	fib6_drop_pcpu_from(rt);
 
 	if (rt->nh) {
 		spin_lock(&rt->nh->lock);
@@ -1138,7 +1128,7 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
 
 			if (rt6_duplicate_nexthop(iter, rt)) {
 				if (rt->fib6_nsiblings)
-					rt->fib6_nsiblings = 0;
+					WRITE_ONCE(rt->fib6_nsiblings, 0);
 				if (!(iter->fib6_flags & RTF_EXPIRES))
 					return -EEXIST;
 				if (!(rt->fib6_flags & RTF_EXPIRES)) {
@@ -1167,7 +1157,8 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
 			 */
 			if (rt_can_ecmp &&
 			    rt6_qualify_for_ecmp(iter))
-				rt->fib6_nsiblings++;
+				WRITE_ONCE(rt->fib6_nsiblings,
+					   rt->fib6_nsiblings + 1);
 		}
 
 		if (iter->fib6_metric > rt->fib6_metric)
@@ -1217,7 +1208,8 @@ next_iter:
 		fib6_nsiblings = 0;
 		list_for_each_entry_safe(sibling, temp_sibling,
 					 &rt->fib6_siblings, fib6_siblings) {
-			sibling->fib6_nsiblings++;
+			WRITE_ONCE(sibling->fib6_nsiblings,
+				   sibling->fib6_nsiblings + 1);
 			BUG_ON(sibling->fib6_nsiblings != rt->fib6_nsiblings);
 			fib6_nsiblings++;
 		}
@@ -1264,8 +1256,9 @@ add:
 				list_for_each_entry_safe(sibling, next_sibling,
 							 &rt->fib6_siblings,
 							 fib6_siblings)
-					sibling->fib6_nsiblings--;
-				rt->fib6_nsiblings = 0;
+					WRITE_ONCE(sibling->fib6_nsiblings,
+						   sibling->fib6_nsiblings - 1);
+				WRITE_ONCE(rt->fib6_nsiblings, 0);
 				list_del_rcu(&rt->fib6_siblings);
 				rcu_read_lock();
 				rt6_multipath_rebalance(next_sibling);
@@ -2014,8 +2007,9 @@ static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,
 			notify_del = true;
 		list_for_each_entry_safe(sibling, next_sibling,
 					 &rt->fib6_siblings, fib6_siblings)
-			sibling->fib6_nsiblings--;
-		rt->fib6_nsiblings = 0;
+			WRITE_ONCE(sibling->fib6_nsiblings,
+				   sibling->fib6_nsiblings - 1);
+		WRITE_ONCE(rt->fib6_nsiblings, 0);
 		list_del_rcu(&rt->fib6_siblings);
 		rt6_multipath_rebalance(next_sibling);
 	}