diff options
| author | Eric Dumazet <edumazet@google.com> | 2019-10-09 15:10:15 -0700 |
|---|---|---|
| committer | Jakub Kicinski <jakub.kicinski@netronome.com> | 2019-10-09 21:35:00 -0700 |
| commit | 1f142c17d19a5618d5a633195a46f2c8be9bf232 (patch) | |
| tree | b64b0a41ac143b7a2eefa20d06eab67a5c4f16da | |
| parent | 60b173ca3d1cd1782bd0096dc17298ec242f6fb1 (diff) | |
tcp: annotate lockless access to tcp_memory_pressure
tcp_memory_pressure is read without holding any lock,
and its value could be changed on other cpus.
Use READ_ONCE() to annotate these lockless reads.
The write side is already using atomic ops.
Fixes: b8da51ebb1aa ("tcp: introduce tcp_under_memory_pressure()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
| -rw-r--r-- | include/net/tcp.h | 2 | ||||
| -rw-r--r-- | net/ipv4/tcp.c | 4 |
2 files changed, 3 insertions, 3 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h index c9a3f9688223..88e63d64c698 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -258,7 +258,7 @@ static inline bool tcp_under_memory_pressure(const struct sock *sk) mem_cgroup_under_socket_pressure(sk->sk_memcg)) return true; - return tcp_memory_pressure; + return READ_ONCE(tcp_memory_pressure); } /* * The next routines deal with comparing 32 bit unsigned ints diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index f98a1882e537..888c92b63f5a 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -326,7 +326,7 @@ void tcp_enter_memory_pressure(struct sock *sk) { unsigned long val; - if (tcp_memory_pressure) + if (READ_ONCE(tcp_memory_pressure)) return; val = jiffies; @@ -341,7 +341,7 @@ void tcp_leave_memory_pressure(struct sock *sk) { unsigned long val; - if (!tcp_memory_pressure) + if (!READ_ONCE(tcp_memory_pressure)) return; val = xchg(&tcp_memory_pressure, 0); if (val) |