| Message ID | 20210628230051.556099-1-toke@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [bpf-next] bpf/devmap: convert remaining READ_ONCE() to rcu_dereference() | expand |
Martin KaFai Lau <kafai@fb.com> writes: > On Tue, Jun 29, 2021 at 01:00:51AM +0200, Toke Høiland-Jørgensen wrote: >> 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@intel.com> >> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.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]); > __dev_map_lookup_elem() uses rcu_dereference_check(dtab->netdev_map[key], rcu_read_lock_bh_held()). > It is not needed here? Hmm, I somehow managed to convince myself last night that it wasn't, but looking at it again now I think you're right. Will send a v2. -Toke
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;
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@intel.com> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> --- kernel/bpf/devmap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)