Commit 1f142c17 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski

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: b8da51eb ("tcp: introduce tcp_under_memory_pressure()")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
parent 60b173ca
...@@ -258,7 +258,7 @@ static inline bool tcp_under_memory_pressure(const struct sock *sk) ...@@ -258,7 +258,7 @@ static inline bool tcp_under_memory_pressure(const struct sock *sk)
mem_cgroup_under_socket_pressure(sk->sk_memcg)) mem_cgroup_under_socket_pressure(sk->sk_memcg))
return true; return true;
return tcp_memory_pressure; return READ_ONCE(tcp_memory_pressure);
} }
/* /*
* The next routines deal with comparing 32 bit unsigned ints * The next routines deal with comparing 32 bit unsigned ints
......
...@@ -326,7 +326,7 @@ void tcp_enter_memory_pressure(struct sock *sk) ...@@ -326,7 +326,7 @@ void tcp_enter_memory_pressure(struct sock *sk)
{ {
unsigned long val; unsigned long val;
if (tcp_memory_pressure) if (READ_ONCE(tcp_memory_pressure))
return; return;
val = jiffies; val = jiffies;
...@@ -341,7 +341,7 @@ void tcp_leave_memory_pressure(struct sock *sk) ...@@ -341,7 +341,7 @@ void tcp_leave_memory_pressure(struct sock *sk)
{ {
unsigned long val; unsigned long val;
if (!tcp_memory_pressure) if (!READ_ONCE(tcp_memory_pressure))
return; return;
val = xchg(&tcp_memory_pressure, 0); val = xchg(&tcp_memory_pressure, 0);
if (val) if (val)
......
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