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authorEric Dumazet <edumazet@google.com>2019-10-10 20:17:44 -0700
committerDavid S. Miller <davem@davemloft.net>2019-10-13 10:13:08 -0700
commitebb3b78db7bf842270a46fd4fe7cc45c78fa5ed6 (patch)
tree9a0ecbc667473f785c77851f2db6c31f1fa3d2a4 /include
parentd9b55bf7b6788ec0bd1db1acefbc4feb1399144a (diff)
tcp: annotate sk->sk_rcvbuf lockless reads
For the sake of tcp_poll(), there are few places where we fetch sk->sk_rcvbuf 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. Note that other transports probably need similar fixes. 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.h4
-rw-r--r--include/trace/events/sock.h2
2 files changed, 3 insertions, 3 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index e1d08f69fd39..ab4eb5eb5d07 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1380,14 +1380,14 @@ static inline int tcp_win_from_space(const struct sock *sk, int space)
/* Note: caller must be prepared to deal with negative returns */
static inline int tcp_space(const struct sock *sk)
{
- return tcp_win_from_space(sk, sk->sk_rcvbuf -
+ return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) -
READ_ONCE(sk->sk_backlog.len) -
atomic_read(&sk->sk_rmem_alloc));
}
static inline int tcp_full_space(const struct sock *sk)
{
- return tcp_win_from_space(sk, sk->sk_rcvbuf);
+ return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf));
}
extern void tcp_openreq_init_rwin(struct request_sock *req,
diff --git a/include/trace/events/sock.h b/include/trace/events/sock.h
index a0c4b8a30966..f720c32e7dfd 100644
--- a/include/trace/events/sock.h
+++ b/include/trace/events/sock.h
@@ -82,7 +82,7 @@ TRACE_EVENT(sock_rcvqueue_full,
TP_fast_assign(
__entry->rmem_alloc = atomic_read(&sk->sk_rmem_alloc);
__entry->truesize = skb->truesize;
- __entry->sk_rcvbuf = sk->sk_rcvbuf;
+ __entry->sk_rcvbuf = READ_ONCE(sk->sk_rcvbuf);
),
TP_printk("rmem_alloc=%d truesize=%u sk_rcvbuf=%d",