netdev - [PATCH bpf-next] bpf/devmap: convert remaining READ_ONCE() to rcu

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Message-Id: <20210628230051.556099-1-toke@redhat.com>
Date:   Tue, 29 Jun 2021 01:00:51 +0200
From:   Toke Høiland-Jørgensen <toke@...hat.com>
To:     bpf@...r.kernel.org, netdev@...r.kernel.org
Cc:     Martin KaFai Lau <kafai@...com>,
        Hangbin Liu <liuhangbin@...il.com>,
        Jesper Dangaard Brouer <brouer@...hat.com>,
        Magnus Karlsson <magnus.karlsson@...il.com>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Jakub Kicinski <kuba@...nel.org>,
        Toke Høiland-Jørgensen <toke@...hat.com>,
        kernel test robot <lkp@...el.com>
Subject: [PATCH bpf-next] bpf/devmap: convert remaining READ_ONCE() to rcu_dereference()

There were a couple of READ_ONCE()-invocations left-over by the devmap RCU
conversion. Convert these to rcu_dereference() as well to avoid complaints
from sparse.

Fixes: 782347b6bcad ("xdp: Add proper __rcu annotations to redirect map entries")
Reported-by: kernel test robot <lkp@...el.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@...hat.com>
---
 kernel/bpf/devmap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 2f6bd75cd682..7a0c008f751b 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -558,7 +558,7 @@ int dev_map_enqueue_multi(struct xdp_buff *xdp, struct net_device *dev_rx,
 
 	if (map->map_type == BPF_MAP_TYPE_DEVMAP) {
 		for (i = 0; i < map->max_entries; i++) {
-			dst = READ_ONCE(dtab->netdev_map[i]);
+			dst = rcu_dereference(dtab->netdev_map[i]);
 			if (!is_valid_dst(dst, xdp, exclude_ifindex))
 				continue;
 
@@ -654,7 +654,7 @@ int dev_map_redirect_multi(struct net_device *dev, struct sk_buff *skb,
 
 	if (map->map_type == BPF_MAP_TYPE_DEVMAP) {
 		for (i = 0; i < map->max_entries; i++) {
-			dst = READ_ONCE(dtab->netdev_map[i]);
+			dst = rcu_dereference(dtab->netdev_map[i]);
 			if (!dst || dst->dev->ifindex == exclude_ifindex)
 				continue;
 
-- 
2.32.0