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authorEric Dumazet <edumazet@google.com>2019-10-11 06:17:42 +0300
committerDavid S. Miller <davem@davemloft.net>2019-10-13 20:13:08 +0300
commite0d694d638dba768b47be31c22e1a9b4f862f561 (patch)
treec35cd9fe92b9008fda870b5ae83b3971e6632a60 /include
parent0f31746452e6793ad6271337438af8f4defb8940 (diff)
downloadlinux-e0d694d638dba768b47be31c22e1a9b4f862f561.tar.xz
tcp: annotate tp->snd_nxt lockless reads
There are few places where we fetch tp->snd_nxt while this field can change from IRQ or other cpu. We need to add READ_ONCE() annotations, and also make sure write sides use corresponding WRITE_ONCE() to avoid store-tearing. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r--include/net/tcp.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 8e7c3f6801a9..e1d08f69fd39 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1917,7 +1917,8 @@ static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp)
static inline bool tcp_stream_memory_free(const struct sock *sk, int wake)
{
const struct tcp_sock *tp = tcp_sk(sk);
- u32 notsent_bytes = READ_ONCE(tp->write_seq) - tp->snd_nxt;
+ u32 notsent_bytes = READ_ONCE(tp->write_seq) -
+ READ_ONCE(tp->snd_nxt);
return (notsent_bytes << wake) < tcp_notsent_lowat(tp);
}