diff options
| author | Eric Dumazet <edumazet@google.com> | 2024-05-03 19:20:57 +0000 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2024-05-07 11:14:50 +0200 |
| commit | 6890ab31d1a35444741e6150db19d64797db2919 (patch) | |
| tree | 9f0e4ae240841eb23698a9c4e45115929997b525 | |
| parent | 6747a5d4990b8c8d7392f7a06b7a4bb5f4ada80e (diff) | |
rtnetlink: do not depend on RTNL in rtnl_fill_proto_down()
Change dev_change_proto_down() and dev_change_proto_down_reason()
to write once on dev->proto_down and dev->proto_down_reason.
Then rtnl_fill_proto_down() can use READ_ONCE() annotations
and run locklessly.
rtnl_proto_down_size() should assume worst case,
because readng dev->proto_down_reason multiple
times would be racy without RTNL in the future.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
| -rw-r--r-- | net/core/dev.c | 11 | ||||
| -rw-r--r-- | net/core/rtnetlink.c | 8 |
2 files changed, 11 insertions, 8 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index d9d9a0d91593..d2ce91a334c1 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -9223,7 +9223,7 @@ int dev_change_proto_down(struct net_device *dev, bool proto_down) netif_carrier_off(dev); else netif_carrier_on(dev); - dev->proto_down = proto_down; + WRITE_ONCE(dev->proto_down, proto_down); return 0; } @@ -9237,18 +9237,21 @@ int dev_change_proto_down(struct net_device *dev, bool proto_down) void dev_change_proto_down_reason(struct net_device *dev, unsigned long mask, u32 value) { + u32 proto_down_reason; int b; if (!mask) { - dev->proto_down_reason = value; + proto_down_reason = value; } else { + proto_down_reason = dev->proto_down_reason; for_each_set_bit(b, &mask, 32) { if (value & (1 << b)) - dev->proto_down_reason |= BIT(b); + proto_down_reason |= BIT(b); else - dev->proto_down_reason &= ~BIT(b); + proto_down_reason &= ~BIT(b); } } + WRITE_ONCE(dev->proto_down_reason, proto_down_reason); } struct bpf_xdp_link { diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 16b5f9c68bbf..dfdd08006fae 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -1036,8 +1036,8 @@ static size_t rtnl_proto_down_size(const struct net_device *dev) { size_t size = nla_total_size(1); - if (dev->proto_down_reason) - size += nla_total_size(0) + nla_total_size(4); + /* Assume dev->proto_down_reason is not zero. */ + size += nla_total_size(0) + nla_total_size(4); return size; } @@ -1737,10 +1737,10 @@ static int rtnl_fill_proto_down(struct sk_buff *skb, struct nlattr *pr; u32 preason; - if (nla_put_u8(skb, IFLA_PROTO_DOWN, dev->proto_down)) + if (nla_put_u8(skb, IFLA_PROTO_DOWN, READ_ONCE(dev->proto_down))) goto nla_put_failure; - preason = dev->proto_down_reason; + preason = READ_ONCE(dev->proto_down_reason); if (!preason) return 0; |