diff options
| author | Eric Dumazet <edumazet@google.com> | 2019-10-10 01:10:15 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-01-27 16:46:50 +0300 |
| commit | a8e920b22026c4717daee0e16ecee828aecfcb84 (patch) | |
| tree | 6f9020144f3067caed0757c3da07fab953786b18 | |
| parent | 681c8c92c4b78e80e0853f8e18861e93069d68e6 (diff) | |
| download | linux-a8e920b22026c4717daee0e16ecee828aecfcb84.tar.xz | |
tcp: annotate lockless access to tcp_memory_pressure
[ Upstream commit 1f142c17d19a5618d5a633195a46f2c8be9bf232 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -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 00d10f0e1194..c96302310314 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -289,7 +289,7 @@ 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 8f07655718f3..db1eceda2359 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -328,7 +328,7 @@ void tcp_enter_memory_pressure(struct sock *sk) { unsigned long val; - if (tcp_memory_pressure) + if (READ_ONCE(tcp_memory_pressure)) return; val = jiffies; @@ -343,7 +343,7 @@ 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) |