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authorEric Dumazet <edumazet@google.com>2019-10-09 15:10:15 -0700
committerJakub Kicinski <jakub.kicinski@netronome.com>2019-10-09 21:35:00 -0700
commit1f142c17d19a5618d5a633195a46f2c8be9bf232 (patch)
treeb64b0a41ac143b7a2eefa20d06eab67a5c4f16da /net
parent60b173ca3d1cd1782bd0096dc17298ec242f6fb1 (diff)
downloadlinux-1f142c17d19a5618d5a633195a46f2c8be9bf232.tar.gz
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>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp.c4
1 files changed, 2 insertions, 2 deletions
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)